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First M87 Event Horizon Telescope Results. VII. Polarization of the RingEvent Horizon Telescope CollaborationAkiyama, KazunoriAlgaba, Juan CarlosAlberdi, AntxonAlef, WalterAnantua, RichardAsada, KeiichiAzulay, RebeccaBaczko, Anne-KathrinBall, DavidBaloković, MislavBarrett, JohnBenson, Bradford A.Bintley, DanBlackburn, LindyBlundell, RaymondBoland, WilfredBouman, Katherine L.Bower, Geoffrey C.Boyce, HopeBremer, MichaelBrinkerink, Christiaan D.Brissenden, RogerBritzen, SilkeBroderick, Avery E.Broguiere, DominiqueBronzwaer, ThomasByun, Do-YoungCarlstrom, John E.Chael, AndrewChan, Chi-kwanChatterjee, ShamiChatterjee, KoushikChen, Ming-TangChen, YongjunChesler, Paul M.Cho, IljeChristian, PierreConway, John E.Cordes, James M.Crawford, Thomas M.Crew, Geoffrey B.Cruz-Osorio, AlejandroCui, YuzhuDavelaar, JordyDe Laurentis, MariafeliciaDeane, RogerDempsey, JessicaDesvignes, GregoryDexter, JasonDoeleman, Sheperd S.Eatough, Ralph P.Falcke, HeinoFarah, JosephFish, Vincent L.Fomalont, EdFord, H. AlysonFraga-Encinas, RaquelFreeman, William T.Friberg, PerFromm, Christian M.Fuentes, AntonioGalison, PeterGammie, Charles F.García, RobertoGentaz, OlivierGeorgiev, BorisGoddi, CiriacoGold, RomanGómez, José L.Gómez-Ruiz, Arturo I.Gu, MinfengGurwell, MarkHada, KazuhiroHaggard, DarylHecht, Michael H.Hesper, RonaldHo, Luis C.Ho, PaulHonma, MarekiHuang, Chih-Wei L.Huang, LeiHughes, David H.Ikeda, ShiroInoue, MakotoIssaoun, SaraJames, David J.Jannuzi, Buell T.Janssen, MichaelJeter, BrittonJiang, WuJimenez-Rosales, AlejandraJohnson, Michael D.Jorstad, SvetlanaJung, TaehyunKarami, MansourKaruppusamy, RameshKawashima, TomohisaKeating, Garrett K.Kettenis, MarkKim, Dong-JinKim, Jae-YoungKim, JongsooKim, JunhanKino, MotokiKoay, Jun YiKofuji, YutaroKoch, Patrick M.Koyama, ShokoKramer, MichaelKramer, CarstenKrichbaum, Thomas P.Kuo, Cheng-YuLauer, Tod R.Lee, Sang-SungLevis, AviadLi, Yan-RongLi, ZhiyuanLindqvist, MichaelLico, RoccoLindahl, GregLiu, JunLiu, KuoLiuzzo, ElisabettaLo, Wen-PingLobanov, Andrei P.Loinard, LaurentLonsdale, ColinLu, Ru-SenMacDonald, Nicholas R.Mao, JirongMarchili, NicolaMarkoff, SeraMarrone, Daniel P.Marscher, Alan P.Martí-Vidal, IvánMatsushita, SatokiMatthews, Lynn D.Medeiros, LiaMenten, Karl M.Mizuno, IzumiMizuno, YosukeMoran, James M.Moriyama, KotaroMoscibrodzka, MonikaMüller, CorneliaMusoke, GibwaMejías, Alejandro MusMichalik, DanielNadolski, AndrewNagai, HiroshiNagar, Neil M.Nakamura, MasanoriNarayan, RameshNarayanan, GopalNatarajan, IniyanNathanail, AntoniosNeilsen, JoeyNeri, RobertoNi, ChunchongNoutsos, AristeidisNowak, Michael A.Okino, HirokiOlivares, HéctorOrtiz-León, Gisela N.Oyama, TomoakiÖzel, FeryalPalumbo, Daniel C. M.Park, JonghoPatel, NimeshPen, Ue-LiPesce, Dominic W.Piétu, VincentPlambeck, RichardPopStefanija, AleksandarPorth, OliverPötzl, Felix M.Prather, BenPreciado-López, Jorge A.Psaltis, DimitriosPu, Hung-YiRamakrishnan, VenkatesshRao, RamprasadRawlings, Mark G.Raymond, Alexander W.Rezzolla, LucianoRicarte, AngeloRipperda, BartRoelofs, FreekRogers, AlanRos, EduardoRose, MelRoshanineshat, ArashRottmann, HelgeRoy, Alan L.Ruszczyk, ChetRygl, Kazi L. J.Sánchez, SalvadorSánchez-Arguelles, DavidSasada, MahitoSavolainen, TuomasSchloerb, F. PeterSchuster, Karl-FriedrichShao, LijingShen, ZhiqiangSmall, DesSohn, Bong WonSooHoo, JasonSun, HeTazaki, FumieTetarenko, Alexandra J.Tiede, PaulTilanus, Remo P. J.Titus, MichaelToma, KenjiTorne, PabloTrent, TylerTraianou, EfthaliaTrippe, Saschavan Bemmel, Ilsevan Langevelde, Huib Janvan Rossum, Daniel R.Wagner, JanWard-Thompson, DerekWardle, JohnWeintroub, JonathanWex, NorbertWharton, RobertWielgus, MaciekWong, George N.Wu, QingwenYoon, DoosooYoung, AndréYoung, KenYounsi, ZiriYuan, FengYuan, Ye-FeiZensus, J. AntonZhao, Guang-YaoZhao, Shan-ShanDOI: info:10.3847/2041-8213/abe71dv. 910L12
Event Horizon Telescope Collaboration, Akiyama, Kazunori, Algaba, Juan Carlos, Alberdi, Antxon, Alef, Walter, Anantua, Richard, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Ball, David, Baloković, Mislav, Barrett, John, Benson, Bradford A., Bintley, Dan, Blackburn, Lindy, Blundell, Raymond, Boland, Wilfred, Bouman, Katherine L., Bower, Geoffrey C., Boyce, Hope, Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broderick, Avery E. et al. 2021. "First M87 Event Horizon Telescope Results. VII. Polarization of the Ring." The Astrophysical Journal 910:L12. https://doi.org/10.3847/2041-8213/abe71d
ID: 159286
Type: article
Authors: Event Horizon Telescope Collaboration; Akiyama, Kazunori; Algaba, Juan Carlos; Alberdi, Antxon; Alef, Walter; Anantua, Richard; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barrett, John; Benson, Bradford A.; Bintley, Dan; Blackburn, Lindy; Blundell, Raymond; Boland, Wilfred; Bouman, Katherine L.; Bower, Geoffrey C.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chael, Andrew; Chan, Chi-kwan; Chatterjee, Shami; Chatterjee, Koushik; Chen, Ming-Tang; Chen, Yongjun; Chesler, Paul M.; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Ed; Ford, H. Alyson; Fraga-Encinas, Raquel; Freeman, William T.; Friberg, Per; Fromm, Christian M.; Fuentes, Antonio; Galison, Peter; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gómez, José L.; Gómez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Kofuji, Yutaro; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Krichbaum, Thomas P.; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Levis, Aviad; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lico, Rocco; Lindahl, Greg; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Marchili, Nicola; Markoff, Sera; Marrone, Daniel P.; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Izumi; Mizuno, Yosuke; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Müller, Cornelia; Musoke, Gibwa; Mejías, Alejandro Mus; Michalik, Daniel; Nadolski, Andrew; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C. M.; Park, Jongho; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Pötzl, Felix M.; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ricarte, Angelo; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Savolainen, Tuomas; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Trent, Tyler; Traianou, Efthalia; Trippe, Sascha; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wielgus, Maciek; Wong, George N.; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guang-Yao; Zhao, Shan-Shan
Abstract: In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. These 1.3 mm wavelength observations revealed a compact asymmetric ring-like source morphology. This structure originates from synchrotron emission produced by relativistic plasma located in the immediate vicinity of the black hole. Here we present the corresponding linear-polarimetric EHT images of the center of M87. We find that only a part of the ring is significantly polarized. The resolved fractional linear polarization has a maximum located in the southwest part of the ring, where it rises to the level of ∼15%. The polarization position angles are arranged in a nearly azimuthal pattern. We perform quantitative measurements of relevant polarimetric properties of the compact emission and find evidence for the temporal evolution of the polarized source structure over one week of EHT observations. The details of the polarimetric data reduction and calibration methodology are provided. We carry out the data analysis using multiple independent imaging and modeling techniques, each of which is validated against a suite of synthetic data sets. The gross polarimetric structure and its apparent evolution with time are insensitive to the method used to reconstruct the image. These polarimetric images carry information about the structure of the magnetic fields responsible for the synchrotron emission. Their physical interpretation is discussed in an accompanying publication.
First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event HorizonEvent Horizon Telescope CollaborationAkiyama, KazunoriAlgaba, Juan CarlosAlberdi, AntxonAlef, WalterAnantua, RichardAsada, KeiichiAzulay, RebeccaBaczko, Anne-KathrinBall, DavidBaloković, MislavBarrett, JohnBenson, Bradford A.Bintley, DanBlackburn, LindyBlundell, RaymondBoland, WilfredBouman, Katherine L.Bower, Geoffrey C.Boyce, HopeBremer, MichaelBrinkerink, Christiaan D.Brissenden, RogerBritzen, SilkeBroderick, Avery E.Broguiere, DominiqueBronzwaer, ThomasByun, Do-YoungCarlstrom, John E.Chael, AndrewChan, Chi-kwanChatterjee, ShamiChatterjee, KoushikChen, Ming-TangChen, YongjunChesler, Paul M.Cho, IljeChristian, PierreConway, John E.Cordes, James M.Crawford, Thomas M.Crew, Geoffrey B.Cruz-Osorio, AlejandroCui, YuzhuDavelaar, JordyDe Laurentis, MariafeliciaDeane, RogerDempsey, JessicaDesvignes, GregoryDexter, JasonDoeleman, Sheperd S.Eatough, Ralph P.Falcke, HeinoFarah, JosephFish, Vincent L.Fomalont, EdFord, H. AlysonFraga-Encinas, RaquelFriberg, PerFromm, Christian M.Fuentes, AntonioGalison, PeterGammie, Charles F.García, RobertoGelles, ZacharyGentaz, OlivierGeorgiev, BorisGoddi, CiriacoGold, RomanGómez, José L.Gómez-Ruiz, Arturo I.Gu, MinfengGurwell, MarkHada, KazuhiroHaggard, DarylHecht, Michael H.Hesper, RonaldHimwich, ElizabethHo, Luis C.Ho, PaulHonma, MarekiHuang, Chih-Wei L.Huang, LeiHughes, David H.Ikeda, ShiroInoue, MakotoIssaoun, SaraJames, David J.Jannuzi, Buell T.Janssen, MichaelJeter, BrittonJiang, WuJimenez-Rosales, AlejandraJohnson, Michael D.Jorstad, SvetlanaJung, TaehyunKarami, MansourKaruppusamy, RameshKawashima, TomohisaKeating, Garrett K.Kettenis, MarkKim, Dong-JinKim, Jae-YoungKim, JongsooKim, JunhanKino, MotokiKoay, Jun YiKofuji, YutaroKoch, Patrick M.Koyama, ShokoKramer, MichaelKramer, CarstenKrichbaum, Thomas P.Kuo, Cheng-YuLauer, Tod R.Lee, Sang-SungLevis, AviadLi, Yan-RongLi, ZhiyuanLindqvist, MichaelLico, RoccoLindahl, GregLiu, JunLiu, KuoLiuzzo, ElisabettaLo, Wen-PingLobanov, Andrei P.Loinard, LaurentLonsdale, ColinLu, Ru-SenMacDonald, Nicholas R.Mao, JirongMarchili, NicolaMarkoff, SeraMarrone, Daniel P.Marscher, Alan P.Martí-Vidal, IvánMatsushita, SatokiMatthews, Lynn D.Medeiros, LiaMenten, Karl M.Mizuno, IzumiMizuno, YosukeMoran, James M.Moriyama, KotaroMoscibrodzka, MonikaMüller, CorneliaMusoke, GibwaMus Mejías, AlejandroMichalik, DanielNadolski, AndrewNagai, HiroshiNagar, Neil M.Nakamura, MasanoriNarayan, RameshNarayanan, GopalNatarajan, IniyanNathanail, AntoniosNeilsen, JoeyNeri, RobertoNi, ChunchongNoutsos, AristeidisNowak, Michael A.Okino, HirokiOlivares, HéctorOrtiz-León, Gisela N.Oyama, TomoakiÖzel, FeryalPalumbo, Daniel C. M.Park, JonghoPatel, NimeshPen, Ue-LiPesce, Dominic W.Piétu, VincentPlambeck, RichardPopStefanija, AleksandarPorth, OliverPötzl, Felix M.Prather, BenPreciado-López, Jorge A.Psaltis, DimitriosPu, Hung-YiRamakrishnan, VenkatesshRao, RamprasadRawlings, Mark G.Raymond, Alexander W.Rezzolla, LucianoRicarte, AngeloRipperda, BartRoelofs, FreekRogers, AlanRos, EduardoRose, MelRoshanineshat, ArashRottmann, HelgeRoy, Alan L.Ruszczyk, ChetRygl, Kazi L. J.Sánchez, SalvadorSánchez-Arguelles, DavidSasada, MahitoSavolainen, TuomasSchloerb, F. PeterSchuster, Karl-FriedrichShao, LijingShen, ZhiqiangSmall, DesSohn, Bong WonSooHoo, JasonSun, HeTazaki, FumieTetarenko, Alexandra J.Tiede, PaulTilanus, Remo P. J.Titus, MichaelToma, KenjiTorne, PabloTrent, TylerTraianou, EfthaliaTrippe, Saschavan Bemmel, Ilsevan Langevelde, Huib Janvan Rossum, Daniel R.Wagner, JanWard-Thompson, DerekWardle, JohnWeintroub, JonathanWex, NorbertWharton, RobertWielgus, MaciekWong, George N.Wu, QingwenYoon, DoosooYoung, AndréYoung, KenYounsi, ZiriYuan, FengYuan, Ye-FeiZensus, J. AntonZhao, Guang-YaoZhao, Shan-ShanDOI: info:10.3847/2041-8213/abe4dev. 910L13
Event Horizon Telescope Collaboration, Akiyama, Kazunori, Algaba, Juan Carlos, Alberdi, Antxon, Alef, Walter, Anantua, Richard, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Ball, David, Baloković, Mislav, Barrett, John, Benson, Bradford A., Bintley, Dan, Blackburn, Lindy, Blundell, Raymond, Boland, Wilfred, Bouman, Katherine L., Bower, Geoffrey C., Boyce, Hope, Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broderick, Avery E. et al. 2021. "First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon." The Astrophysical Journal 910:L13. https://doi.org/10.3847/2041-8213/abe4de
ID: 159442
Type: article
Authors: Event Horizon Telescope Collaboration; Akiyama, Kazunori; Algaba, Juan Carlos; Alberdi, Antxon; Alef, Walter; Anantua, Richard; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barrett, John; Benson, Bradford A.; Bintley, Dan; Blackburn, Lindy; Blundell, Raymond; Boland, Wilfred; Bouman, Katherine L.; Bower, Geoffrey C.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chael, Andrew; Chan, Chi-kwan; Chatterjee, Shami; Chatterjee, Koushik; Chen, Ming-Tang; Chen, Yongjun; Chesler, Paul M.; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Ed; Ford, H. Alyson; Fraga-Encinas, Raquel; Friberg, Per; Fromm, Christian M.; Fuentes, Antonio; Galison, Peter; Gammie, Charles F.; García, Roberto; Gelles, Zachary; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gómez, José L.; Gómez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Hecht, Michael H.; Hesper, Ronald; Himwich, Elizabeth; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Kofuji, Yutaro; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Krichbaum, Thomas P.; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Levis, Aviad; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lico, Rocco; Lindahl, Greg; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Marchili, Nicola; Markoff, Sera; Marrone, Daniel P.; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Izumi; Mizuno, Yosuke; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Müller, Cornelia; Musoke, Gibwa; Mus Mejías, Alejandro; Michalik, Daniel; Nadolski, Andrew; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C. M.; Park, Jongho; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Pötzl, Felix M.; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ricarte, Angelo; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Savolainen, Tuomas; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Trent, Tyler; Traianou, Efthalia; Trippe, Sascha; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wielgus, Maciek; Wong, George N.; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guang-Yao; Zhao, Shan-Shan
Abstract: Event Horizon Telescope (EHT) observations at 230 GHz have now imaged polarized emission around the supermassive black hole in M87 on event-horizon scales. This polarized synchrotron radiation probes the structure of magnetic fields and the plasma properties near the black hole. Here we compare the resolved polarization structure observed by the EHT, along with simultaneous unresolved observations with the Atacama Large Millimeter/submillimeter Array, to expectations from theoretical models. The low fractional linear polarization in the resolved image suggests that the polarization is scrambled on scales smaller than the EHT beam, which we attribute to Faraday rotation internal to the emission region. We estimate the average density ne ∼ 104-7 cm-3, magnetic field strength B ∼ 1-30 G, and electron temperature Te ∼ (1-12) × 1010 K of the radiating plasma in a simple one-zone emission model. We show that the net azimuthal linear polarization pattern may result from organized, poloidal magnetic fields in the emission region. In a quantitative comparison with a large library of simulated polarimetric images from general relativistic magnetohydrodynamic (GRMHD) simulations, we identify a subset of physical models that can explain critical features of the polarimetric EHT observations while producing a relativistic jet of sufficient power. The consistent GRMHD models are all of magnetically arrested accretion disks, where near-horizon magnetic fields are dynamically important. We use the models to infer a mass accretion rate onto the black hole in M87 of (3-20) × 10-4 M yr-1.
Polarimetric Properties of Event Horizon Telescope Targets from ALMAGoddi, CiriacoMartí-Vidal, IvánMessias, HugoBower, Geoffrey C.Broderick, Avery E.Dexter, JasonMarrone, Daniel P.Moscibrodzka, MonikaNagai, HiroshiAlgaba, Juan CarlosAsada, KeiichiCrew, Geoffrey B.Gómez, José L.Impellizzeri, C. M. VioletteJanssen, MichaelKadler, MatthiasKrichbaum, Thomas P.Lico, RoccoMatthews, Lynn D.Nathanail, AntoniosRicarte, AngeloRos, EduardoYounsi, ZiriAkiyama, KazunoriAlberdi, AntxonAlef, WalterAnantua, RichardAzulay, RebeccaBaczko, Anne-KathrinBall, DavidBaloković, MislavBarrett, JohnBenson, Bradford A.Bintley, DanBlackburn, LindyBlundell, RaymondBoland, WilfredBouman, Katherine L.Boyce, HopeBremer, MichaelBrinkerink, Christiaan D.Brissenden, RogerBritzen, SilkeBroguiere, DominiqueBronzwaer, ThomasByun, Do-YoungCarlstrom, John E.Chael, AndrewChan, Chi-kwanChatterjee, ShamiChatterjee, KoushikChen, Ming-TangChen, YongjunChesler, Paul M.Cho, IljeChristian, PierreConway, John E.Cordes, James M.Crawford, Thomas M.Cruz-Osorio, AlejandroCui, YuzhuDavelaar, JordyDe Laurentis, MariafeliciaDeane, RogerDempsey, JessicaDesvignes, GregoryDoeleman, Sheperd S.Eatough, Ralph P.Falcke, HeinoFarah, JosephFish, Vincent L.Fomalont, EdFord, H. AlysonFraga-Encinas, RaquelFreeman, William T.Friberg, PerFromm, Christian M.Fuentes, AntonioGalison, PeterGammie, Charles F.García, RobertoGentaz, OlivierGeorgiev, BorisGold, RomanGómez-Ruiz, Arturo I.Gu, MinfengGurwell, MarkHada, KazuhiroHaggard, DarylHecht, Michael H.Hesper, RonaldHo, Luis C.Ho, PaulHonma, MarekiHuang, Chih-Wei L.Huang, LeiHughes, David H.Inoue, MakotoIssaoun, SaraJames, David J.Jannuzi, Buell T.Jeter, BrittonJiang, WuJimenez-Rosales, AlejandraJohnson, Michael D.Jorstad, SvetlanaJung, TaehyunKarami, MansourKaruppusamy, RameshKawashima, TomohisaKeating, Garrett K.Kettenis, MarkKim, Dong-JinKim, Jae-YoungKim, JongsooKim, JunhanKino, MotokiKoay, Jun YiKofuji, YutaroKoch, Patrick M.Koyama, ShokoKramer, MichaelKramer, CarstenKuo, Cheng-YuLauer, Tod R.Lee, Sang-SungLevis, AviadLi, Yan-RongLi, ZhiyuanLindqvist, MichaelLindahl, GregLiu, JunLiu, KuoLiuzzo, ElisabettaLo, Wen-PingLobanov, Andrei P.Loinard, LaurentLonsdale, ColinLu, Ru-SenMacDonald, Nicholas R.Mao, JirongMarchili, NicolaMarkoff, SeraMarscher, Alan P.Matsushita, SatokiMedeiros, LiaMenten, Karl M.Mizuno, IzumiMizuno, YosukeMoran, James M.Moriyama, KotaroMüller, CorneliaMusoke, GibwaMejías, Alejandro MusNagar, Neil M.Nakamura, MasanoriNarayan, RameshNarayanan, GopalNatarajan, IniyanNeilsen, JoeyNeri, RobertoNi, ChunchongNoutsos, AristeidisNowak, Michael A.Okino, HirokiOlivares, HéctorOrtiz-León, Gisela N.Oyama, TomoakiÖzel, FeryalPalumbo, Daniel C. M.Park, JonghoPatel, NimeshPen, Ue-LiPesce, Dominic W.Piétu, VincentPlambeck, RichardPopStefanija, AleksandarPorth, OliverPötzl, Felix M.Prather, BenPreciado-López, Jorge A.Psaltis, DimitriosPu, Hung-YiRamakrishnan, VenkatesshRao, RamprasadRawlings, Mark G.Raymond, Alexander W.Rezzolla, LucianoRipperda, BartRoelofs, FreekRogers, AlanRose, MelRoshanineshat, ArashRottmann, HelgeRoy, Alan L.Ruszczyk, ChetRygl, Kazi L. J.Sánchez, SalvadorSánchez-Arguelles, DavidSasada, MahitoSavolainen, TuomasSchloerb, F. PeterSchuster, Karl-FriedrichShao, LijingShen, ZhiqiangSmall, DesSohn, Bong WonSooHoo, JasonSun, HeTazaki, FumieTetarenko, Alexandra J.Tiede, PaulTilanus, Remo P. J.Titus, MichaelToma, KenjiTorne, PabloTrent, TylerTraianou, EfthaliaTrippe, Saschavan Bemmel, Ilsevan Langevelde, Huib Janvan Rossum, Daniel R.Wagner, JanWard-Thompson, DerekWardle, JohnWeintroub, JonathanWex, NorbertWharton, RobertWielgus, MaciekWong, George N.Wu, QingwenYoon, DoosooYoung, AndréYoung, KenYuan, FengYuan, Ye-FeiZensus, J. AntonZhao, Guang-YaoZhao, Shan-ShanBruni, GabrieleGopakumar, A.Hernández-Gómez, AntonioHerrero-Illana, RubenIngram, AdamKomossa, S.Kovalev, Y. Y.Muders, DirkPerucho, ManelRösch, FlorianValtonen, MauriDOI: info:10.3847/2041-8213/abee6av. 910L14
Goddi, Ciriaco, Martí-Vidal, Iván, Messias, Hugo, Bower, Geoffrey C., Broderick, Avery E., Dexter, Jason, Marrone, Daniel P., Moscibrodzka, Monika, Nagai, Hiroshi, Algaba, Juan Carlos, Asada, Keiichi, Crew, Geoffrey B., Gómez, José L., Impellizzeri, C. M. Violette, Janssen, Michael, Kadler, Matthias, Krichbaum, Thomas P., Lico, Rocco, Matthews, Lynn D., Nathanail, Antonios, Ricarte, Angelo, Ros, Eduardo, Younsi, Ziri, Akiyama, Kazunori, Alberdi, Antxon et al. 2021. "Polarimetric Properties of Event Horizon Telescope Targets from ALMA." The Astrophysical Journal 910:L14. https://doi.org/10.3847/2041-8213/abee6a
ID: 159441
Type: article
Authors: Goddi, Ciriaco; Martí-Vidal, Iván; Messias, Hugo; Bower, Geoffrey C.; Broderick, Avery E.; Dexter, Jason; Marrone, Daniel P.; Moscibrodzka, Monika; Nagai, Hiroshi; Algaba, Juan Carlos; Asada, Keiichi; Crew, Geoffrey B.; Gómez, José L.; Impellizzeri, C. M. Violette; Janssen, Michael; Kadler, Matthias; Krichbaum, Thomas P.; Lico, Rocco; Matthews, Lynn D.; Nathanail, Antonios; Ricarte, Angelo; Ros, Eduardo; Younsi, Ziri; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Anantua, Richard; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barrett, John; Benson, Bradford A.; Bintley, Dan; Blackburn, Lindy; Blundell, Raymond; Boland, Wilfred; Bouman, Katherine L.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chael, Andrew; Chan, Chi-kwan; Chatterjee, Shami; Chatterjee, Koushik; Chen, Ming-Tang; Chen, Yongjun; Chesler, Paul M.; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Ed; Ford, H. Alyson; Fraga-Encinas, Raquel; Freeman, William T.; Friberg, Per; Fromm, Christian M.; Fuentes, Antonio; Galison, Peter; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Gold, Roman; Gómez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Kofuji, Yutaro; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Levis, Aviad; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lindahl, Greg; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Marchili, Nicola; Markoff, Sera; Marscher, Alan P.; Matsushita, Satoki; Medeiros, Lia; Menten, Karl M.; Mizuno, Izumi; Mizuno, Yosuke; Moran, James M.; Moriyama, Kotaro; Müller, Cornelia; Musoke, Gibwa; Mejías, Alejandro Mus; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C. M.; Park, Jongho; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Pötzl, Felix M.; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Savolainen, Tuomas; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Trent, Tyler; Traianou, Efthalia; Trippe, Sascha; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wielgus, Maciek; Wong, George N.; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guang-Yao; Zhao, Shan-Shan; Bruni, Gabriele; Gopakumar, A.; Hernández-Gómez, Antonio; Herrero-Illana, Ruben; Ingram, Adam; Komossa, S.; Kovalev, Y. Y.; Muders, Dirk; Perucho, Manel; Rösch, Florian; Valtonen, Mauri
Abstract: We present the results from a full polarization study carried out with the Atacama Large Millimeter/submillimeter Array (ALMA) during the first Very Long Baseline Interferometry (VLBI) campaign, which was conducted in 2017 April in the λ3 mm and λ1.3 mm bands, in concert with the Global mm-VLBI Array (GMVA) and the Event Horizon Telescope (EHT), respectively. We determine the polarization and Faraday properties of all VLBI targets, including Sgr A*, M87, and a dozen radio-loud active galactic nuclei (AGNs), in the two bands at several epochs in a time window of 10 days. We detect high linear polarization fractions (2%-15%) and large rotation measures (RM > 103.3-105.5 rad m-2), confirming the trends of previous AGN studies at millimeter wavelengths. We find that blazars are more strongly polarized than other AGNs in the sample, while exhibiting (on average) order-of-magnitude lower RM values, consistent with the AGN viewing angle unification scheme. For Sgr A* we report a mean RM of (-4.2 ± 0.3) × 105 rad m-2 at 1.3 mm, consistent with measurements over the past decade and, for the first time, an RM of (-2.1 ± 0.1) × 105 rad m-2 at 3 mm, suggesting that about half of the Faraday rotation at 1.3 mm may occur between the 3 mm photosphere and the 1.3 mm source. We also report the first unambiguous measurement of RM toward the M87 nucleus at millimeter wavelengths, which undergoes significant changes in magnitude and sign reversals on a one year timescale, spanning the range from -1.2 to 0.3 × 105 rad m-2 at 3 mm and -4.1 to 1.5 × 105 rad m-2 at 1.3 mm. Given this time variability, we argue that, unlike the case of Sgr A*, the RM in M87 does not provide an accurate estimate of the mass accretion rate onto the black hole. We put forward a two-component model, comprised of a variable compact region and a static extended region, that can simultaneously explain the polarimetric properties observed by both the EHT (on horizon scales) and ALMA (which observes the combined emission from both components). These measurements provide critical constraints for the calibration, analysis, and interpretation of simultaneously obtained VLBI data with the EHT and GMVA.
Evaluation of New Submillimeter VLBI Sites for the Event Horizon TelescopeRaymond, Alexander W.Palumbo, DanielPaine, Scott N.Blackburn, LindyCórdova Rosado, RodrigoDoeleman, Sheperd S.Farah, Joseph R.Johnson, Michael D.Roelofs, FreekTilanus, Remo P. J.Weintroub, JonathanDOI: info:10.3847/1538-3881/abc3c3v. 2535
Raymond, Alexander W., Palumbo, Daniel, Paine, Scott N., Blackburn, Lindy, Córdova Rosado, Rodrigo, Doeleman, Sheperd S., Farah, Joseph R., Johnson, Michael D., Roelofs, Freek, Tilanus, Remo P. J., and Weintroub, Jonathan. 2021. "Evaluation of New Submillimeter VLBI Sites for the Event Horizon Telescope." The Astrophysical Journal Supplement Series 253:5. https://doi.org/10.3847/1538-3881/abc3c3
ID: 159443
Type: article
Authors: Raymond, Alexander W.; Palumbo, Daniel; Paine, Scott N.; Blackburn, Lindy; Córdova Rosado, Rodrigo; Doeleman, Sheperd S.; Farah, Joseph R.; Johnson, Michael D.; Roelofs, Freek; Tilanus, Remo P. J.; Weintroub, Jonathan
Abstract: The Event Horizon Telescope (EHT) is a very long-baseline interferometer built to image supermassive black holes on event-horizon scales. In this paper, we investigate candidate sites for an expanded EHT array with improved imaging capabilities. We use historical meteorology and radiative transfer analysis to evaluate site performance. Most of the existing sites in the EHT array have median zenith opacity less than 0.2 at 230 GHz during the March/April observing season. Seven of the existing EHT sites have 345 GHz opacity less than 0.5 during observing months. Out of more than 40 candidate new locations analyzed, approximately half have 230 GHz opacity comparable to the existing EHT sites, and at least 17 of the candidate sites would be comparably good for 345 GHz observing. A group of new sites with favorable transmittance and geographic placement leads to greatly enhanced imaging and science on horizon scales.
Closure Statistics in Interferometric DataBlackburn, LindyPesce, Dominic W.Johnson, Michael D.Wielgus, MaciekChael, Andrew A.Christian, PierreDoeleman, Sheperd S.DOI: info:10.3847/1538-4357/ab8469v. 89431
Blackburn, Lindy, Pesce, Dominic W., Johnson, Michael D., Wielgus, Maciek, Chael, Andrew A., Christian, Pierre, and Doeleman, Sheperd S. 2020. "Closure Statistics in Interferometric Data." The Astrophysical Journal 894:31. https://doi.org/10.3847/1538-4357/ab8469
ID: 156958
Type: article
Authors: Blackburn, Lindy; Pesce, Dominic W.; Johnson, Michael D.; Wielgus, Maciek; Chael, Andrew A.; Christian, Pierre; Doeleman, Sheperd S.
Abstract: Interferometric visibilities, reflecting the complex correlations between signals recorded at antennas in an interferometric array, carry information about the angular structure of a distant source. While unknown antenna gains in both amplitude and phase can prevent direct interpretation of these measurements, certain combinations of visibilities called closure phases and closure amplitudes are independent of antenna gains and provide a convenient set of robust observables. However, these closure quantities have subtle noise properties and are generally both linearly and statistically dependent. These complications have obstructed the proper use of closure quantities in interferometric analysis, and they have obscured the relationship between analysis with closure quantities and other analysis techniques such as self calibration. We review the statistics of closure quantities, noting common pitfalls that arise when approaching low signal to noise due to the nonlinear propagation of statistical errors. We then develop a strategy for isolating and fitting to the independent degrees of freedom captured by the closure quantities through explicit construction of linearly independent sets of quantities along with their noise covariance in the Gaussian limit, valid for moderate signal to noise, and we demonstrate that model fits have biased posteriors when this covariance is ignored. Finally, we introduce a unified procedure for fitting to both closure information and partially calibrated visibilities, and we demonstrate both analytically and numerically the direct equivalence of inference based on closure quantities to that based on self calibration of complex visibilities with unconstrained antenna gains.
THEMIS: A Parameter Estimation Framework for the Event Horizon TelescopeBroderick, Avery E.Gold, RomanKarami, MansourPreciado-López, Jorge A.Tiede, PaulPu, Hung-YiAkiyama, KazunoriAlberdi, AntxonAlef, WalterAsada, KeiichiAzulay, RebeccaBaczko, Anne-KathrinBaloković, MislavBarrett, JohnBintley, DanBlackburn, LindyBoland, WilfredBouman, Katherine L.Bower, Geoffrey C.Bremer, MichaelBrinkerink, Christiaan D.Brissenden, RogerBritzen, SilkeBroguiere, DominiqueBronzwaer, ThomasByun, Do-YoungCarlstrom, John E.Chael, AndrewChatterjee, ShamiChatterjee, KoushikChen, Ming-TangChen, YongjunCho, IljeConway, John E.Cordes, James M.Crew, Geoffrey B.Cui, YuzhuDavelaar, JordyDe Laurentis, MariafeliciaDeane, RogerDempsey, JessicaDesvignes, GregoryDoeleman, Sheperd S.Eatough, Ralph P.Falcke, HeinoFish, Vincent L.Fomalont, EdFraga-Encinas, RaquelFriberg, PerFromm, Christian M.Galison, PeterGammie, Charles F.García, RobertoGentaz, OlivierGeorgiev, BorisGoddi, CiriacoGómez, José L.Gu, MinfengGurwell, MarkHada, KazuhiroHecht, Michael H.Hesper, RonaldHo, Luis C.Ho, PaulHonma, MarekiHuang, Chih-Wei L.Huang, LeiHughes, David H.Inoue, MakotoIssaoun, SaraJames, David J.Janssen, MichaelJeter, BrittonJiang, WuJiménez-Rosales, AlejandraJohnson, Michael D.Jorstad, SvetlanaJung, TaehyunKaruppusamy, RameshKawashima, TomohisaKeating, Garrett K.Kettenis, MarkKim, Jae-YoungKim, JongsooKino, MotokiKoay, Jun YiKoch, Patrick M.Koyama, ShokoKramer, MichaelKramer, CarstenKrichbaum, Thomas P.Kuo, Cheng-YuLee, Sang-SungLi, Yan-RongLi, ZhiyuanLindqvist, MichaelLico, RoccoLiu, KuoLiuzzo, ElisabettaLo, Wen-PingLobanov, Andrei P.Loinard, LaurentLonsdale, ColinLu, Ru-SenMacDonald, Nicholas R.Mao, JirongMarscher, Alan P.Martí-Vidal, IvánMatsushita, SatokiMatthews, Lynn D.Menten, Karl M.Mizuno, YosukeMizuno, IzumiMoran, James M.Moriyama, KotaroMoscibrodzka, MonikaMüller, CorneliaNagai, HiroshiNagar, Neil M.Nakamura, MasanoriNarayan, RameshNarayanan, GopalNatarajan, IniyanNeri, RobertoNi, ChunchongNoutsos, AristeidisOkino, HirokiOlivares, HéctorOrtiz-León, Gisela N.Oyama, TomoakiPalumbo, Daniel C. M.Park, JonghoPen, Ue-LiPesce, Dominic W.Piétu, VincentPlambeck, RichardPopStefanija, AleksandarPorth, OliverPrather, BenRamakrishnan, VenkatesshRao, RamprasadRawlings, Mark G.Raymond, Alexander W.Rezzolla, LucianoRipperda, BartRoelofs, FreekRogers, AlanRos, EduardoRose, MelRottmann, HelgeRuszczyk, ChetRyan, Benjamin R.Rygl, Kazi L. J.Sánchez, SalvadorSánchez-Arguelles, DavidSasada, MahitoSavolainen, TuomasSchloerb, F. PeterSchuster, Karl-FriedrichShao, LijingShen, ZhiqiangSmall, DesSohn, Bong WonSooHoo, JasonTazaki, FumieTilanus, Remo P. J.Titus, MichaelToma, KenjiTorne, PabloTraianou, EfthaliaTrippe, SaschaTsuda, Shuichirovan Bemmel, Ilsevan Langevelde, Huib Janvan Rossum, Daniel R.Wagner, JanWardle, JohnWeintroub, JonathanWex, NorbertWharton, RobertWielgus, MaciekWong, George N.Wu, QingwenYoon, DoosooYoung, AndréYoung, KenYounsi, ZiriYuan, FengYuan, Ye-FeiZensus, J. AntonZhao, GuangyaoZhao, Shan-ShanZhu, ZiyanEvent Horizon Telescope CollaborationDOI: info:10.3847/1538-4357/ab91a4v. 897139
Broderick, Avery E., Gold, Roman, Karami, Mansour, Preciado-López, Jorge A., Tiede, Paul, Pu, Hung-Yi, Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Baloković, Mislav, Barrett, John, Bintley, Dan, Blackburn, Lindy, Boland, Wilfred, Bouman, Katherine L., Bower, Geoffrey C., Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broguiere, Dominique, Bronzwaer, Thomas et al. 2020. "THEMIS: A Parameter Estimation Framework for the Event Horizon Telescope." The Astrophysical Journal 897:139. https://doi.org/10.3847/1538-4357/ab91a4
ID: 157837
Type: article
Authors: Broderick, Avery E.; Gold, Roman; Karami, Mansour; Preciado-López, Jorge A.; Tiede, Paul; Pu, Hung-Yi; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Baloković, Mislav; Barrett, John; Bintley, Dan; Blackburn, Lindy; Boland, Wilfred; Bouman, Katherine L.; Bower, Geoffrey C.; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chael, Andrew; Chatterjee, Shami; Chatterjee, Koushik; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Conway, John E.; Cordes, James M.; Crew, Geoffrey B.; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Fish, Vincent L.; Fomalont, Ed; Fraga-Encinas, Raquel; Friberg, Per; Fromm, Christian M.; Galison, Peter; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gómez, José L.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Inoue, Makoto; Issaoun, Sara; James, David J.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jiménez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Jung, Taehyun; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Jae-Young; Kim, Jongsoo; Kino, Motoki; Koay, Jun Yi; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Krichbaum, Thomas P.; Kuo, Cheng-Yu; Lee, Sang-Sung; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lico, Rocco; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Menten, Karl M.; Mizuno, Yosuke; Mizuno, Izumi; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Müller, Cornelia; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Palumbo, Daniel C. M.; Park, Jongho; Pen, Ue-Li; Pesce, Dominic W.; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Prather, Ben; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Rottmann, Helge; Ruszczyk, Chet; Ryan, Benjamin R.; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Savolainen, Tuomas; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Tazaki, Fumie; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Traianou, Efthalia; Trippe, Sascha; Tsuda, Shuichiro; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wielgus, Maciek; Wong, George N.; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guangyao; Zhao, Shan-Shan; Zhu, Ziyan; Event Horizon Telescope Collaboration
Abstract: The Event Horizon Telescope (EHT) provides the unprecedented ability to directly resolve the structure and dynamics of black hole emission regions on scales smaller than their horizons. This has the potential to critically probe the mechanisms by which black holes accrete and launch outflows, and the structure of supermassive black hole spacetimes. However, accessing this information is a formidable analysis challenge for two reasons. First, the EHT natively produces a variety of data types that encode information about the image structure in nontrivial ways; these are subject to a variety of systematic effects associated with very long baseline interferometry and are supplemented by a wide variety of auxiliary data on the primary EHT targets from decades of other observations. Second, models of the emission regions and their interaction with the black hole are complex, highly uncertain, and computationally expensive to construct. As a result, the scientific utilization of EHT observations requires a flexible, extensible, and powerful analysis framework. We present such a framework, THEMIS, which defines a set of interfaces between models, data, and sampling algorithms that facilitates future development. We describe the design and currently existing components of THEMIS, how THEMIS has been validated thus far, and present additional analyses made possible by THEMIS that illustrate its capabilities. Importantly, we demonstrate that THEMIS is able to reproduce prior EHT analyses, extend these, and do so in a computationally efficient manner that can efficiently exploit modern high-performance computing facilities. THEMIS has already been used extensively in the scientific analysis and interpretation of the first EHT observations of M87.
Verification of Radiative Transfer Schemes for the EHTGold, RomanBroderick, Avery E.Younsi, ZiriFromm, Christian M.Gammie, Charles F.Mościbrodzka, MonikaPu, Hung-YiBronzwaer, ThomasDavelaar, JordyDexter, JasonBall, DavidChan, Chi-kwanKawashima, TomohisaMizuno, YosukeRipperda, BartAkiyama, KazunoriAlberdi, AntxonAlef, WalterAsada, KeiichiAzulay, RebeccaBaczko, Anne-KathrinBaloković, MislavBarrett, JohnBintley, DanBlackburn, LindyBoland, WilfredBouman, Katherine L.Bower, Geoffrey C.Bremer, MichaelBrinkerink, Christiaan D.Brissenden, RogerBritzen, SilkeBroguiere, DominiqueByun, Do-YoungCarlstrom, John E.Chael, AndrewChatterjee, KoushikChatterjee, ShamiChen, Ming-TangChen, YongjunCho, IljeChristian, PierreConway, John E.Cordes, James M.Crew, Geoffrey B.Cui, YuzhuDe Laurentis, MariafeliciaDeane, RogerDempsey, JessicaDesvignes, GregoryDoeleman, Sheperd S.Eatough, Ralph?PFalcke, HeinoFish, Vincent L.Fomalont, EdFraga-Encinas, RaquelFreeman, BillFriberg, PerGómez, José L.Galison, PeterGarcía, RobertoGentaz, OlivierGeorgiev, BorisGoddi, CiriacoGu, MinfengGurwell, MarkHada, KazuhiroHecht, Michael H.Hesper, RonaldHo, Luis C.Ho, PaulHonma, MarekiHuang, Chih-Wei L.Huang, LeiHughes, David H.Inoue, MakotoIssaoun, SaraJames, David J.Jannuzi, Buell T.Janssen, MichaelJeter, BrittonJiang, WuJimenez-Rosales, AlejandraJohnson, Michael D.Jorstad, SvetlanaJung, TaehyunKarami, MansourKaruppusamy, RameshKeating, Garrett K.Kettenis, MarkKim, Jae-YoungKim, JunhanKim, JongsooKino, MotokiKoay, Jun YiKoch, Patrick M.Koyama, ShokoKramer, MichaelKramer, CarstenKrichbaum, Thomas P.Kuo, Cheng-YuLauer, Tod R.Lee, Sang-SungLi, Yan-RongLi, ZhiyuanLico, RoccoLindqvist, MichaelLiu, KuoLiuzzo, ElisabettaLo, Wen-PingLobanov, Andrei P.Loinard, LaurentLonsdale, ColinLu, Ru-SenMacDonald, Nicholas R.Markoff, SeraMao, JirongMarrone, Daniel P.Marscher, Alan P.Martí-Vidal, IvánMatsushita, SatokiMatthews, Lynn D.Medeiros, LiaMenten, Karl M.Mizuno, IzumiMoran, James M.Moriyama, KotaroMüller, CorneliaNagai, HiroshiNakamura, MasanoriNagar, Neil M.Narayan, RameshNarayanan, GopalNatarajan, IniyanNeri, RobertoNi, ChunchongNoutsos, AristeidisOkino, HirokiOrtiz-León, Gisela N.Oyama, TomoakiÖzel, FeryalPalumbo, Daniel C. M.Park, JonghoPatel, NimeshPen, Ue-LiPesce, Dominic W.Plambeck, RichardPiétu, VincentPopStefanija, AleksandarPorth, OliverPreciado-López, Jorge A.Psaltis, DimitriosRamakrishnan, VenkatesshRao, RamprasadRawlings, Mark G.Raymond, Alexander W.Rezzolla, LucianoRoelofs, FreekRogers, AlanRos, EduardoRose, MelRoshanineshat, ArashRottmann, HelgeRoy, Alan L.Ruszczyk, ChetRygl, Kazi L. J.Sánchez, SalvadorSánchez-Arguelles, DavidSasada, MahitoSavolainen, TuomasSchuster, Karl-FriedrichSchloerb, F. PeterShao, LijingShen, ZhiqiangSmall, DesSohn, Bong WonSooHoo, JasonTiede, PaulTazaki, FumieTilanus, Remo P. J.Titus, MichaelToma, KenjiTorne, PabloTrent, TylerTraianou, ThaliaTrippe, SaschaTsuda, Shuichirovan Langevelde, Huib Janvan Bemmel, Ilsevan Rossum, Daniel R.Wagner, JanWardle, JohnWex, NorbertWeintroub, JonathanWharton, RobertWielgus, MaciekWong, George N.Wu, QingwenYoon, DoosooYoung, KenYoung, AndréYuan, FengYuan, Ye-FeiZensus, J. AntonZhao, GuangyaoZhao, Shan-ShanZhu, ZiyanEvent Horizon Telescope CollaborationDOI: info:10.3847/1538-4357/ab96c6v. 897148
Gold, Roman, Broderick, Avery E., Younsi, Ziri, Fromm, Christian M., Gammie, Charles F., Mościbrodzka, Monika, Pu, Hung-Yi, Bronzwaer, Thomas, Davelaar, Jordy, Dexter, Jason, Ball, David, Chan, Chi-kwan, Kawashima, Tomohisa, Mizuno, Yosuke, Ripperda, Bart, Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Baloković, Mislav, Barrett, John, Bintley, Dan, Blackburn, Lindy et al. 2020. "Verification of Radiative Transfer Schemes for the EHT." The Astrophysical Journal 897:148. https://doi.org/10.3847/1538-4357/ab96c6
ID: 157835
Type: article
Authors: Gold, Roman; Broderick, Avery E.; Younsi, Ziri; Fromm, Christian M.; Gammie, Charles F.; Mościbrodzka, Monika; Pu, Hung-Yi; Bronzwaer, Thomas; Davelaar, Jordy; Dexter, Jason; Ball, David; Chan, Chi-kwan; Kawashima, Tomohisa; Mizuno, Yosuke; Ripperda, Bart; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Baloković, Mislav; Barrett, John; Bintley, Dan; Blackburn, Lindy; Boland, Wilfred; Bouman, Katherine L.; Bower, Geoffrey C.; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broguiere, Dominique; Byun, Do-Young; Carlstrom, John E.; Chael, Andrew; Chatterjee, Koushik; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crew, Geoffrey B.; Cui, Yuzhu; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Doeleman, Sheperd S.; Eatough, Ralph?P; Falcke, Heino; Fish, Vincent L.; Fomalont, Ed; Fraga-Encinas, Raquel; Freeman, Bill; Friberg, Per; Gómez, José L.; Galison, Peter; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Keating, Garrett K.; Kettenis, Mark; Kim, Jae-Young; Kim, Junhan; Kim, Jongsoo; Kino, Motoki; Koay, Jun Yi; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Krichbaum, Thomas P.; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Li, Yan-Rong; Li, Zhiyuan; Lico, Rocco; Lindqvist, Michael; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Markoff, Sera; Mao, Jirong; Marrone, Daniel P.; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Izumi; Moran, James M.; Moriyama, Kotaro; Müller, Cornelia; Nagai, Hiroshi; Nakamura, Masanori; Nagar, Neil M.; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Okino, Hiroki; Ortiz-León, Gisela N.; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C. M.; Park, Jongho; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Plambeck, Richard; Piétu, Vincent; PopStefanija, Aleksandar; Porth, Oliver; Preciado-López, Jorge A.; Psaltis, Dimitrios; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Savolainen, Tuomas; Schuster, Karl-Friedrich; Schloerb, F. Peter; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Tiede, Paul; Tazaki, Fumie; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Trent, Tyler; Traianou, Thalia; Trippe, Sascha; Tsuda, Shuichiro; van Langevelde, Huib Jan; van Bemmel, Ilse; van Rossum, Daniel R.; Wagner, Jan; Wardle, John; Wex, Norbert; Weintroub, Jonathan; Wharton, Robert; Wielgus, Maciek; Wong, George N.; Wu, Qingwen; Yoon, Doosoo; Young, Ken; Young, André; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guangyao; Zhao, Shan-Shan; Zhu, Ziyan; Event Horizon Telescope Collaboration
Abstract: The Event Horizon Telescope (EHT) Collaboration has recently produced the first resolved images of the central supermassive black hole in the giant elliptical galaxy M87. Here we report on tests of the consistency and accuracy of the general relativistic radiative transfer codes used within the collaboration to model M87* and Sgr A*. We compare and evaluate (1) deflection angles for equatorial null geodesics in a Kerr spacetime; (2) images calculated from a series of simple, parameterized matter distributions in the Kerr metric using simplified emissivities and absorptivities; (3) for a subset of codes, images calculated from general relativistic magnetohydrodynamics simulations using different realistic synchrotron emissivities and absorptivities; (4) observables for the 2017 configuration of EHT, including visibility amplitudes and closure phases. The error in total flux is of order 1% when the codes are run with production numerical parameters. The dominant source of discrepancies for small camera distances is the location and detailed setup of the software "camera" that each code uses to produce synthetic images. We find that when numerical parameters are suitably chosen and the camera is sufficiently far away the images converge and that for given transfer coefficients, numerical uncertainties are unlikely to limit parameter estimation for the current generation of EHT observations. The purpose of this paper is to describe a verification and comparison of EHT radiative transfer codes. It is not to verify EHT models more generally.
Universal interferometric signatures of a black hole's photon ringJohnson, Michael D.Lupsasca, AlexandruStrominger, AndrewWong, George N.Hadar, ShaharKapec, DanielNarayan, RameshChael, AndrewGammie, Charles F.Galison, PeterPalumbo, Daniel C. M.Doeleman, Sheperd S.Blackburn, LindyWielgus, MaciekPesce, Dominic W.Farah, Joseph R.Moran, James M.DOI: info:10.1126/sciadv.aaz1310v. 6eaaz1310
Johnson, Michael D., Lupsasca, Alexandru, Strominger, Andrew, Wong, George N., Hadar, Shahar, Kapec, Daniel, Narayan, Ramesh, Chael, Andrew, Gammie, Charles F., Galison, Peter, Palumbo, Daniel C. M., Doeleman, Sheperd S., Blackburn, Lindy, Wielgus, Maciek, Pesce, Dominic W., Farah, Joseph R., and Moran, James M. 2020. "Universal interferometric signatures of a black hole's photon ring." Science Advances 6:eaaz1310. https://doi.org/10.1126/sciadv.aaz1310
ID: 158202
Type: article
Authors: Johnson, Michael D.; Lupsasca, Alexandru; Strominger, Andrew; Wong, George N.; Hadar, Shahar; Kapec, Daniel; Narayan, Ramesh; Chael, Andrew; Gammie, Charles F.; Galison, Peter; Palumbo, Daniel C. M.; Doeleman, Sheperd S.; Blackburn, Lindy; Wielgus, Maciek; Pesce, Dominic W.; Farah, Joseph R.; Moran, James M.
Abstract: The Event Horizon Telescope image of the supermassive black hole in the galaxy M87 is dominated by a bright, unresolved ring. General relativity predicts that embedded within this image lies a thin "photon ring," which is composed of an infinite sequence of self-similar subrings that are indexed by the number of photon orbits around the black hole. The subrings approach the edge of the black hole "shadow," becoming exponentially narrower but weaker with increasing orbit number, with seemingly negligible contributions from high order subrings. Here, we show that these subrings produce strong and universal signatures on long interferometric baselines. These signatures offer the possibility of precise measurements of black hole mass and spin, as well as tests of general relativity, using only a sparse interferometric array.
Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolutionKim, Jae-YoungKrichbaum, Thomas P.Broderick, Avery E.Wielgus, MaciekBlackburn, LindyGómez, José L.Johnson, Michael D.Bouman, Katherine L.Chael, AndrewAkiyama, KazunoriJorstad, SvetlanaMarscher, Alan P.Issaoun, SaraJanssen, MichaelChan, Chi-kwanSavolainen, TuomasPesce, Dominic W.Özel, FeryalAlberdi, AntxonAlef, WalterAsada, KeiichiAzulay, RebeccaBaczko, Anne-KathrinBall, DavidBaloković, MislavBarrett, JohnBintley, DanBoland, WilfredBower, Geoffrey C.Bremer, MichaelBrinkerink, Christiaan D.Brissenden, RogerBritzen, SilkeBroguiere, DominiqueBronzwaer, ThomasByun, Do-YoungCarlstrom, John E.Chatterjee, ShamiChatterjee, KoushikChen, Ming-TangChen, YongjunCho, IljeChristian, PierreConway, John E.Cordes, James M.Crew, Geoffrey B.Cui, YuzhuDavelaar, JordyDe Laurentis, MariafeliciaDeane, RogerDempsey, JessicaDesvignes, GregoryDexter, JasonDoeleman, Sheperd S.Eatough, Ralph P.Falcke, HeinoFish, Vincent L.Fomalont, EdFraga-Encinas, RaquelFriberg, PerFromm, Christian M.Galison, PeterGammie, Charles F.García, RobertoGentaz, OlivierGeorgiev, BorisGoddi, CiriacoGold, RomanGómez-Ruiz, Arturo I.Gu, MinfengGurwell, MarkHada, KazuhiroHecht, Michael H.Hesper, RonaldHo, Luis C.Ho, PaulHonma, MarekiHuang, Chih-Wei L.Huang, LeiHughes, David H.Ikeda, ShiroInoue, MakotoJames, David J.Jannuzi, Buell T.Jeter, BrittonJiang, WuJimenez-Rosales, AlejandraJung, TaehyunKarami, MansourKaruppusamy, RameshKawashima, TomohisaKeating, Garrett K.Kettenis, MarkKim, JunhanKim, JongsooKino, MotokiKoay, Jun YiKoch, Patrick M.Koyama, ShokoKramer, MichaelKramer, CarstenKuo, Cheng-YuLauer, Tod R.Lee, Sang-SungLi, Yan-RongLi, ZhiyuanLindqvist, MichaelLico, RoccoLiu, KuoLiuzzo, ElisabettaLo, Wen-PingLobanov, Andrei P.Loinard, LaurentLonsdale, ColinLu, Ru-SenMacDonald, Nicholas R.Mao, JirongMarkoff, SeraMarrone, Daniel P.Martí-Vidal, IvánMatsushita, SatokiMatthews, Lynn D.Medeiros, LiaMenten, Karl M.Mizuno, YosukeMizuno, IzumiMoran, James M.Moriyama, KotaroMoscibrodzka, MonikaMusoke, GibwaMüller, CorneliaNagai, HiroshiNagar, Neil M.Nakamura, MasanoriNarayan, RameshNarayanan, GopalNatarajan, IniyanNeri, RobertoNi, ChunchongNoutsos, AristeidisOkino, HirokiOlivares, HéctorOrtiz-León, Gisela N.Oyama, TomoakiPalumbo, Daniel C. M.Park, JonghoPatel, NimeshPen, Ue-LiPiétu, VincentPlambeck, RichardPopStefanija, AleksandarPorth, OliverPrather, BenPreciado-López, Jorge A.Psaltis, DimitriosPu, Hung-YiRamakrishnan, VenkatesshRao, RamprasadRawlings, Mark G.Raymond, Alexander W.Rezzolla, LucianoRipperda, BartRoelofs, FreekRogers, AlanRos, EduardoRose, MelRoshanineshat, ArashRottmann, HelgeRoy, Alan L.Ruszczyk, ChetRyan, Benjamin R.Rygl, Kazi L. J.Sánchez, SalvadorSánchez-Arguelles, DavidSasada, MahitoSchloerb, F. PeterSchuster, Karl-FriedrichShao, LijingShen, ZhiqiangSmall, DesSohn, Bong WonSooHoo, JasonTazaki, FumieTiede, PaulTilanus, Remo P. J.Titus, MichaelToma, KenjiTorne, PabloTrent, TylerTraianou, EfthaliaTrippe, SaschaTsuda, Shuichirovan Bemmel, Ilsevan Langevelde, Huib Janvan Rossum, Daniel R.Wagner, JanWardle, JohnWard-Thompson, DerekWeintroub, JonathanWex, NorbertWharton, RobertWong, George N.Wu, QingwenYoon, DoosooYoung, AndréYoung, KenYounsi, ZiriYuan, FengYuan, Ye-FeiZensus, J. AntonZhao, GuangyaoZhao, Shan-ShanZhu, ZiyanAlgaba, Juan-CarlosAllardi, AlexanderAmestica, RodrigoAnczarski, JadynBach, UweBaganoff, Frederick K.Beaudoin, ChristopherBenson, Bradford A.Berthold, RyanBlanchard, Jay M.Blundell, RayBustamente, SandraCappallo, RogerCastillo-Domínguez, EdgarChang, Chih-ChengChang, Shu-HaoChang, Song-ChuChen, Chung-ChenChilson, RyanChuter, Tim C.Rosado, Rodrigo CórdovaCoulson, Iain M.Crowley, JosephDerome, MarkDexter, MatthewDornbusch, SvenDudevoir, Kevin A.Dzib, Sergio A.Eckart, AndreasEckert, ChrisErickson, Neal R.Everett, Wendeline B.Faber, AaronFarah, Joseph R.Fath, VernonFolkers, Thomas W.Forbes, David C.Freund, RobertGale, David M.Gao, FengGeertsema, GertieGraham, David A.Greer, Christopher H.Grosslein, RonaldGueth, FrédéricHaggard, DarylHalverson, Nils W.Han, Chih-ChiangHan, Kuo-ChangHao, JinchiHasegawa, YutakaHenning, Jason W.Hernández-Gómez, AntonioHerrero-Illana, RubénHeyminck, StefanHirota, AkihikoHoge, JamesHuang, Yau-DeViolette Impellizzeri, C. M.Jiang, HominJohn, DavidKamble, AtishKeisler, RyanKimura, KimihiroKono, YusukeKubo, DerekKuroda, JohnLacasse, RichardLaing, Robert A.Leitch, Erik M.Li, Chao-TeLin, Lupin C. -CLiu, Ching-TangLiu, Kuan-YuLu, Li-MingMarson, Ralph G.Martin-Cocher, Pierre L.Massingill, Kyle D.Matulonis, CallieMcColl, Martin P.McWhirter, Stephen R.Messias, HugoMeyer-Zhao, ZhengMichalik, DanielMontaña, AlfredoMontgomerie, WilliamMora-Klein, MatiasMuders, DirkNadolski, AndrewNavarro, SantiagoNeilsen, JosephNguyen, Chi H.Nishioka, HiroakiNorton, TimothyNowak, Michael A.Nystrom, GeorgeOgawa, HideoOshiro, PeterParsons, HarrietPeñalver, JuanPhillips, Neil M.Poirier, MichaelPradel, NicolasPrimiani, Rurik A.Raffin, Philippe A.Rahlin, Alexandra S.Reiland, GeorgeRisacher, ChristopherRuiz, IgnacioSáez-Madaín, Alejandro F.Sassella, RemiSchellart, PimShaw, PaulSilva, Kevin M.Shiokawa, HotakaSmith, David R.Snow, WilliamSouccar, KamalSousa, DonSridharan, Tirupati K.Srinivasan, RanjaniStahm, WilliamStark, Antony A.Story, KyleTimmer, Sjoerd T.Vertatschitsch, LauraWalther, CraigWei, Ta-ShunWhitehorn, NathanWhitney, Alan R.Woody, David P.Wouterloot, Jan G. A.Wright, MelvinYamaguchi, PaulYu, Chen-YuZeballos, MilagrosZhang, ShuoZiurys, LucyEvent Horizon Telescope CollaborationDOI: info:10.1051/0004-6361/202037493v. 640A69
Kim, Jae-Young, Krichbaum, Thomas P., Broderick, Avery E., Wielgus, Maciek, Blackburn, Lindy, Gómez, José L., Johnson, Michael D., Bouman, Katherine L., Chael, Andrew, Akiyama, Kazunori, Jorstad, Svetlana, Marscher, Alan P., Issaoun, Sara, Janssen, Michael, Chan, Chi-kwan, Savolainen, Tuomas, Pesce, Dominic W., Özel, Feryal, Alberdi, Antxon, Alef, Walter, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Ball, David, Baloković, Mislav et al. 2020. "Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution." Astronomy and Astrophysics 640:A69. https://doi.org/10.1051/0004-6361/202037493
ID: 157610
Type: article
Authors: Kim, Jae-Young; Krichbaum, Thomas P.; Broderick, Avery E.; Wielgus, Maciek; Blackburn, Lindy; Gómez, José L.; Johnson, Michael D.; Bouman, Katherine L.; Chael, Andrew; Akiyama, Kazunori; Jorstad, Svetlana; Marscher, Alan P.; Issaoun, Sara; Janssen, Michael; Chan, Chi-kwan; Savolainen, Tuomas; Pesce, Dominic W.; Özel, Feryal; Alberdi, Antxon; Alef, Walter; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barrett, John; Bintley, Dan; Boland, Wilfred; Bower, Geoffrey C.; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chatterjee, Shami; Chatterjee, Koushik; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crew, Geoffrey B.; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Fish, Vincent L.; Fomalont, Ed; Fraga-Encinas, Raquel; Friberg, Per; Fromm, Christian M.; Galison, Peter; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gómez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Inoue, Makoto; James, David J.; Jannuzi, Buell T.; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Junhan; Kim, Jongsoo; Kino, Motoki; Koay, Jun Yi; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lico, Rocco; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Markoff, Sera; Marrone, Daniel P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Yosuke; Mizuno, Izumi; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Musoke, Gibwa; Müller, Cornelia; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Palumbo, Daniel C. M.; Park, Jongho; Patel, Nimesh; Pen, Ue-Li; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Ryan, Benjamin R.; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Tazaki, Fumie; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Trent, Tyler; Traianou, Efthalia; Trippe, Sascha; Tsuda, Shuichiro; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Wardle, John; Ward-Thompson, Derek; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wong, George N.; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guangyao; Zhao, Shan-Shan; Zhu, Ziyan; Algaba, Juan-Carlos; Allardi, Alexander; Amestica, Rodrigo; Anczarski, Jadyn; Bach, Uwe; Baganoff, Frederick K.; Beaudoin, Christopher; Benson, Bradford A.; Berthold, Ryan; Blanchard, Jay M.; Blundell, Ray; Bustamente, Sandra; Cappallo, Roger; Castillo-Domínguez, Edgar; Chang, Chih-Cheng; Chang, Shu-Hao; Chang, Song-Chu; Chen, Chung-Chen; Chilson, Ryan; Chuter, Tim C.; Rosado, Rodrigo Córdova; Coulson, Iain M.; Crowley, Joseph; Derome, Mark; Dexter, Matthew; Dornbusch, Sven; Dudevoir, Kevin A.; Dzib, Sergio A.; Eckart, Andreas; Eckert, Chris; Erickson, Neal R.; Everett, Wendeline B.; Faber, Aaron; Farah, Joseph R.; Fath, Vernon; Folkers, Thomas W.; Forbes, David C.; Freund, Robert; Gale, David M.; Gao, Feng; Geertsema, Gertie; Graham, David A.; Greer, Christopher H.; Grosslein, Ronald; Gueth, Frédéric; Haggard, Daryl; Halverson, Nils W.; Han, Chih-Chiang; Han, Kuo-Chang; Hao, Jinchi; Hasegawa, Yutaka; Henning, Jason W.; Hernández-Gómez, Antonio; Herrero-Illana, Rubén; Heyminck, Stefan; Hirota, Akihiko; Hoge, James; Huang, Yau-De; Violette Impellizzeri, C. M.; Jiang, Homin; John, David; Kamble, Atish; Keisler, Ryan; Kimura, Kimihiro; Kono, Yusuke; Kubo, Derek; Kuroda, John; Lacasse, Richard; Laing, Robert A.; Leitch, Erik M.; Li, Chao-Te; Lin, Lupin C. -C; Liu, Ching-Tang; Liu, Kuan-Yu; Lu, Li-Ming; Marson, Ralph G.; Martin-Cocher, Pierre L.; Massingill, Kyle D.; Matulonis, Callie; McColl, Martin P.; McWhirter, Stephen R.; Messias, Hugo; Meyer-Zhao, Zheng; Michalik, Daniel; Montaña, Alfredo; Montgomerie, William; Mora-Klein, Matias; Muders, Dirk; Nadolski, Andrew; Navarro, Santiago; Neilsen, Joseph; Nguyen, Chi H.; Nishioka, Hiroaki; Norton, Timothy; Nowak, Michael A.; Nystrom, George; Ogawa, Hideo; Oshiro, Peter; Oyama, Tomoaki; Parsons, Harriet; Peñalver, Juan; Phillips, Neil M.; Poirier, Michael; Pradel, Nicolas; Primiani, Rurik A.; Raffin, Philippe A.; Rahlin, Alexandra S.; Reiland, George; Risacher, Christopher; Ruiz, Ignacio; Sáez-Madaín, Alejandro F.; Sassella, Remi; Schellart, Pim; Shaw, Paul; Silva, Kevin M.; Shiokawa, Hotaka; Smith, David R.; Snow, William; Souccar, Kamal; Sousa, Don; Sridharan, Tirupati K.; Srinivasan, Ranjani; Stahm, William; Stark, Antony A.; Story, Kyle; Timmer, Sjoerd T.; Vertatschitsch, Laura; Walther, Craig; Wei, Ta-Shun; Whitehorn, Nathan; Whitney, Alan R.; Woody, David P.; Wouterloot, Jan G. A.; Wright, Melvin; Yamaguchi, Paul; Yu, Chen-Yu; Zeballos, Milagros; Zhang, Shuo; Ziurys, Lucy; Event Horizon Telescope Collaboration
Abstract: 3C 279 is an archetypal blazar with a prominent radio jet that show broadband flux density variability across the entire electromagnetic spectrum. We use an ultra-high angular resolution technique - global Very Long Baseline Interferometry (VLBI) at 1.3 mm (230 GHz) - to resolve the innermost jet of 3C 279 in order to study its fine-scale morphology close to the jet base where highly variable γ-ray emission is thought to originate, according to various models. The source was observed during four days in April 2017 with the Event Horizon Telescope at 230 GHz, including the phased Atacama Large Millimeter/submillimeter Array (ALMA), at an angular resolution of ∼20 μas (at a redshift of z = 0.536 this corresponds to ∼0.13 pc ∼ 1700 Schwarzschild radii with a black hole mass MBH = 8 × 108 M). Imaging and model-fitting techniques were applied to the data to parameterize the fine-scale source structure and its variation. We find a multicomponent inner jet morphology with the northernmost component elongated perpendicular to the direction of the jet, as imaged at longer wavelengths. The elongated nuclear structure is consistent on all four observing days and across different imaging methods and model-fitting techniques, and therefore appears robust. Owing to its compactness and brightness, we associate the northern nuclear structure as the VLBI "core". This morphology can be interpreted as either a broad resolved jet base or a spatially bent jet. We also find significant day-to-day variations in the closure phases, which appear most pronounced on the triangles with the longest baselines. Our analysis shows that this variation is related to a systematic change of the source structure. Two inner jet components move non-radially at apparent speeds of ∼15 c and ∼20 c (∼1.3 and ∼1.7 μas day-1, respectively), which more strongly supports the scenario of traveling shocks or instabilities in a bent, possibly rotating jet. The observed apparent speeds are also coincident with the 3C 279 large-scale jet kinematics observed at longer (cm) wavelengths, suggesting no significant jet acceleration between the 1.3 mm core and the outer jet. The intrinsic brightness temperature of the jet components are ≲1010 K, a magnitude or more lower than typical values seen at ≥7 mm wavelengths. The low brightness temperature and morphological complexity suggest that the core region of 3C 279 becomes optically thin at short (mm) wavelengths.
The data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/640/A69 and at http://https://eventhorizontelescope.org/for-astronomers/data
SYMBA: An end-to-end VLBI synthetic data generation pipeline. Simulating Event Horizon Telescope observations of M 87Roelofs, F.Janßen, M.Natarajan, I.Deane, R.Davelaar, J.Olivares, H.Porth, O.Paine, Scott N.Bouman, Katherine L.Tilanus, R. P. J.van Bemmel, I. M.Falcke, H.Akiyama, K.Alberdi, A.Alef, W.Asada, K.Azulay, R.Baczko, A.Ball, D.Baloković, MislavBarrett, J.Bintley, D.Blackburn, LindyBoland, W.Bower, G. C.Bremer, M.Brinkerink, C. D.Brissenden, RogerBritzen, S.Broderick, A. E.Broguiere, D.Bronzwaer, T.Byun, D.Carlstrom, J. E.Chael, A.Chan, C.Chatterjee, S.Chatterjee, K.Chen, M.Chen, Y.Cho, I.Christian, P.Conway, J. E.Cordes, J. M.Crew, G. B.Cui, Y.De Laurentis, M.Dempsey, J.Desvignes, G.Dexter, J.Doeleman, Sheperd S.Eatough, R. P.Fish, V. L.Fomalont, E.Fraga-Encinas, R.Friberg, P.Fromm, C. M.Gómez, J. L.Galison, P.Gammie, C. F.García, R.Gentaz, O.Georgiev, B.Goddi, C.Gold, R.Gu, M.Gurwell, MarkHada, K.Hecht, M. H.Hesper, R.Ho, L. C.Ho, P.Honma, M.Huang, C. L.Huang, L.Hughes, D. H.Ikeda, S.Inoue, M.Issaoun, S.James, David J.Jannuzi, B. T.Jeter, B.Jiang, W.Johnson, M. D.Jorstad, S.Jung, T.Karami, M.Karuppusamy, R.Kawashima, T.Keating, Garrett K.Kettenis, M.Kim, J.Kino, M.Koay, J. Y.Koch, P. M.Koyama, S.Kramer, M.Kramer, C.Krichbaum, T. P.Kuo, C.Lauer, T. R.Lee, S.Li, Y.Li, Z.Lindqvist, M.Lico, R.Liu, K.Liuzzo, E.Lo, W.Lobanov, A. P.Loinard, L.Lonsdale, C.Lu, R.MacDonald, N. R.Mao, J.Markoff, S.Marrone, D. P.Marscher, A. P.Martí-Vidal, I.Matsushita, S.Matthews, L. D.Medeiros, L.Menten, K. M.Mizuno, Y.Mizuno, I.Moran, James M.Moriyama, K.Moscibrodzka, M.Müller, C.Nagai, H.Nagar, N. M.Nakamura, M.Narayan, RameshNarayanan, G.Neri, R.Ni, C.Noutsos, A.Okino, H.Ortiz-León, G. N.Oyama, T.Özel, F.Palumbo, Daniel C. M.Patel, NimeshPen, U.Pesce, Dominic W.Piétu, V.Plambeck, R.PopStefanija, A.Prather, B.Preciado-López, J. A.Psaltis, D.Pu, H.Ramakrishnan, V.Rao, R.Rawlings, M. G.Raymond, Alexander W.Rezzolla, L.Ripperda, B.Rogers, A.Ros, E.Rose, M.Roshanineshat, A.Rottmann, H.Roy, A. L.Ruszczyk, C.Ryan, B. R.Rygl, K. L. J.Sánchez, S.Sánchez-Arguelles, D.Sasada, M.Savolainen, T.Schloerb, F. P.Schuster, K.Shao, L.Shen, Z.Small, D.Won Sohn, B.SooHoo, J.Tazaki, F.Tiede, P.Titus, M.Toma, K.Torne, P.Traianou, E.Trent, T.Trippe, S.Tsuda, S.van Langevelde, H. J.van Rossum, D. R.Wagner, J.Wardle, J.Weintroub, JonathanWex, N.Wharton, R.Wielgus, MaciekWong, G. N.Wu, Q.Young, A.Young, K.Younsi, Z.Yuan, F.Yuan, Y.Zensus, J. A.Zhao, G.Zhao, S.Zhu, Z.DOI: info:10.1051/0004-6361/201936622v. 636A5
Roelofs, F., Janßen, M., Natarajan, I., Deane, R., Davelaar, J., Olivares, H., Porth, O., Paine, Scott N., Bouman, Katherine L., Tilanus, R. P. J., van Bemmel, I. M., Falcke, H., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A., Ball, D., Baloković, Mislav, Barrett, J., Bintley, D., Blackburn, Lindy, Boland, W., Bower, G. C. et al. 2020. "SYMBA: An end-to-end VLBI synthetic data generation pipeline. Simulating Event Horizon Telescope observations of M 87." Astronomy and Astrophysics 636:A5. https://doi.org/10.1051/0004-6361/201936622
ID: 157120
Type: article
Authors: Roelofs, F.; Janßen, M.; Natarajan, I.; Deane, R.; Davelaar, J.; Olivares, H.; Porth, O.; Paine, Scott N.; Bouman, Katherine L.; Tilanus, R. P. J.; van Bemmel, I. M.; Falcke, H.; Akiyama, K.; Alberdi, A.; Alef, W.; Asada, K.; Azulay, R.; Baczko, A.; Ball, D.; Baloković, Mislav; Barrett, J.; Bintley, D.; Blackburn, Lindy; Boland, W.; Bower, G. C.; Bremer, M.; Brinkerink, C. D.; Brissenden, Roger; Britzen, S.; Broderick, A. E.; Broguiere, D.; Bronzwaer, T.; Byun, D.; Carlstrom, J. E.; Chael, A.; Chan, C.; Chatterjee, S.; Chatterjee, K.; Chen, M.; Chen, Y.; Cho, I.; Christian, P.; Conway, J. E.; Cordes, J. M.; Crew, G. B.; Cui, Y.; De Laurentis, M.; Dempsey, J.; Desvignes, G.; Dexter, J.; Doeleman, Sheperd S.; Eatough, R. P.; Fish, V. L.; Fomalont, E.; Fraga-Encinas, R.; Friberg, P.; Fromm, C. M.; Gómez, J. L.; Galison, P.; Gammie, C. F.; García, R.; Gentaz, O.; Georgiev, B.; Goddi, C.; Gold, R.; Gu, M.; Gurwell, Mark; Hada, K.; Hecht, M. H.; Hesper, R.; Ho, L. C.; Ho, P.; Honma, M.; Huang, C. L.; Huang, L.; Hughes, D. H.; Ikeda, S.; Inoue, M.; Issaoun, S.; James, David J.; Jannuzi, B. T.; Jeter, B.; Jiang, W.; Johnson, M. D.; Jorstad, S.; Jung, T.; Karami, M.; Karuppusamy, R.; Kawashima, T.; Keating, Garrett K.; Kettenis, M.; Kim, J.; Kim, J.; Kim, J.; Kino, M.; Koay, J. Y.; Koch, P. M.; Koyama, S.; Kramer, M.; Kramer, C.; Krichbaum, T. P.; Kuo, C.; Lauer, T. R.; Lee, S.; Li, Y.; Li, Z.; Lindqvist, M.; Lico, R.; Liu, K.; Liuzzo, E.; Lo, W.; Lobanov, A. P.; Loinard, L.; Lonsdale, C.; Lu, R.; MacDonald, N. R.; Mao, J.; Markoff, S.; Marrone, D. P.; Marscher, A. P.; Martí-Vidal, I.; Matsushita, S.; Matthews, L. D.; Medeiros, L.; Menten, K. M.; Mizuno, Y.; Mizuno, I.; Moran, James M.; Moriyama, K.; Moscibrodzka, M.; Müller, C.; Nagai, H.; Nagar, N. M.; Nakamura, M.; Narayan, Ramesh; Narayanan, G.; Neri, R.; Ni, C.; Noutsos, A.; Okino, H.; Olivares, H.; Ortiz-León, G. N.; Oyama, T.; Özel, F.; Palumbo, Daniel C. M.; Patel, Nimesh; Pen, U.; Pesce, Dominic W.; Piétu, V.; Plambeck, R.; PopStefanija, A.; Prather, B.; Preciado-López, J. A.; Psaltis, D.; Pu, H.; Ramakrishnan, V.; Rao, R.; Rawlings, M. G.; Raymond, Alexander W.; Rezzolla, L.; Ripperda, B.; Rogers, A.; Ros, E.; Rose, M.; Roshanineshat, A.; Rottmann, H.; Roy, A. L.; Ruszczyk, C.; Ryan, B. R.; Rygl, K. L. J.; Sánchez, S.; Sánchez-Arguelles, D.; Sasada, M.; Savolainen, T.; Schloerb, F. P.; Schuster, K.; Shao, L.; Shen, Z.; Small, D.; Won Sohn, B.; SooHoo, J.; Tazaki, F.; Tiede, P.; Titus, M.; Toma, K.; Torne, P.; Traianou, E.; Trent, T.; Trippe, S.; Tsuda, S.; van Langevelde, H. J.; van Rossum, D. R.; Wagner, J.; Wardle, J.; Weintroub, Jonathan; Wex, N.; Wharton, R.; Wielgus, Maciek; Wong, G. N.; Wu, Q.; Young, A.; Young, K.; Younsi, Z.; Yuan, F.; Yuan, Y.; Zensus, J. A.; Zhao, G.; Zhao, S.; Zhu, Z.
Abstract: Context. Realistic synthetic observations of theoretical source models are essential for our understanding of real observational data. In using synthetic data, one can verify the extent to which source parameters can be recovered and evaluate how various data corruption effects can be calibrated. These studies are the most important when proposing observations of new sources, in the characterization of the capabilities of new or upgraded instruments, and when verifying model-based theoretical predictions in a direct comparison with observational data.
Aims: We present the SYnthetic Measurement creator for long Baseline Arrays (SYMBA), a novel synthetic data generation pipeline for Very Long Baseline Interferometry (VLBI) observations. SYMBA takes into account several realistic atmospheric, instrumental, and calibration effects.
Methods: We used SYMBA to create synthetic observations for the Event Horizon Telescope (EHT), a millimetre VLBI array, which has recently captured the first image of a black hole shadow. After testing SYMBA with simple source and corruption models, we study the importance of including all corruption and calibration effects, compared to the addition of thermal noise only. Using synthetic data based on two example general relativistic magnetohydrodynamics (GRMHD) model images of M 87, we performed case studies to assess the image quality that can be obtained with the current and future EHT array for different weather conditions.
Results: Our synthetic observations show that the effects of atmospheric and instrumental corruptions on the measured visibilities are significant. Despite these effects, we demonstrate how the overall structure of our GRMHD source models can be recovered robustly with the EHT2017 array after performing calibration steps, which include fringe fitting, a priori amplitude and network calibration, and self-calibration. With the planned addition of new stations to the EHT array in the coming years, images could be reconstructed with higher angular resolution and dynamic range. In our case study, these improvements allowed for a distinction between a thermal and a non-thermal GRMHD model based on salient features in reconstructed images.
Monitoring the Morphology of M87* in 2009-2017 with the Event Horizon TelescopeWielgus, MaciekAkiyama, KazunoriBlackburn, LindyChan, Chi-kwanDexter, JasonDoeleman, Sheperd S.Fish, Vincent L.Issaoun, SaraJohnson, Michael D.Krichbaum, Thomas P.Lu, Ru-SenPesce, Dominic W.Wong, George N.Bower, Geoffrey C.Broderick, Avery E.Chael, AndrewChatterjee, KoushikGammie, Charles F.Georgiev, BorisHada, KazuhiroLoinard, LaurentMarkoff, SeraMarrone, Daniel P.Plambeck, RichardWeintroub, JonathanDexter, MatthewMacMahon, David H. E.Wright, MelvynAlberdi, AntxonAlef, WalterAsada, KeiichiAzulay, RebeccaBaczko, Anne-KathrinBall, DavidBaloković, MislavBarausse, EnricoBarrett, JohnBintley, DanBoland, WilfredBouman, Katherine L.Bremer, MichaelBrinkerink, Christiaan D.Brissenden, RogerBritzen, SilkeBroguiere, DominiqueBronzwaer, ThomasByun, Do-YoungCarlstrom, John E.Chatterjee, ShamiChen, Ming-TangChen, YongjunCho, IljeChristian, PierreConway, John E.Cordes, James M.Crew, Geoffrey B.Cui, YuzhuDavelaar, JordyDe Laurentis, MariafeliciaeDeane, RogerDempsey, JessicaDesvignes, GregoryDzib, Sergio A.Eatough, Ralph P.Falcke, HeinoFomalont, EdFraga-Encinas, RaquelFriberg, PerFromm, Christian M.Galison, PeterGarcía, RobertoGentaz, OlivierGoddi, CiriacoGold, RomanGómez, José L.Gómez-Ruiz, Arturo I.Gu, MinfengGurwell, MarkHecht, Michael H.Hesper, RonaldHo, Luis C.Ho, PaulHonma, MarekiHuang, Chih-Wei L.Huang, LeiHughes, David H.Inoue, MakotoJames, David J.Jannuzi, Buell T.Janssen, MichaelJeter, BrittonJiang, WuJimenez-Rosales, AlejandraJorstad, SvetlanaJung, TaehyunKarami, MansourKaruppusamy, RameshKawashima, TomohisaKeating, Garrett K.Kettenis, MarkKim, Jae-YoungKim, JunhanKim, JongsooKino, MotokiKoay, Jun YiKoch, Patrick M.Koyama, ShokoKramer, MichaelKramer, CarstenKuo, Cheng-YuLauer, Tod R.Lee, Sang-SungLi, Yan-RongLi, ZhiyuanLindqvist, MichaelLico, RoccoLiu, KuoLiuzzo, ElisabettaLo, Wen-PingLobanov, Andrei P.Lonsdale, ColinMacDonald, Nicholas R.Mao, JirongMarchili, NicolaMarscher, Alan P.Martí-Vidal, IvánMatsushita, SatokiMatthews, Lynn D.Medeiros, LiaMenten, Karl M.Mizuno, YosukeMizuno, IzumiMoran, James M.Moriyama, KotaroMoscibrodzka, MonikaMüller, CorneliaMusoke, GibwaNagai, HiroshiNagar, Neil M.Nakamura, MasanoriNarayan, RameshNarayanan, GopalNatarajan, IniyanNathanail, AntoniosNeri, RobertoNi, ChunchongNoutsos, AristeidisOkino, HirokiOlivares, HéctorOrtiz-León, Gisela N.Oyama, TomoakiÖzel, FeryalPalumbo, Daniel C. M.Park, JonghoPatel, NimeshPen, Ue-LiPiétu, VincentPopStefanija, AleksandarPorth, OliverPrather, BenPreciado-López, Jorge A.Psaltis, DimitriosPu, Hung-YiRamakrishnan, VenkatesshRao, RamprasadRawlings, Mark G.Raymond, Alexander W.Rezzolla, LucianoRipperda, BartRoelofs, FreekRogers, AlanRos, EduardoRose, MelRoshanineshat, ArashRottmann, HelgeRoy, Alan L.Ruszczyk, ChetRyan, Benjamin R.Rygl, Kazi L. J.Sánchez, SalvadorSánchez-Arguelles, DavidSasada, MahitoSavolainen, TuomasSchloerb, F. PeterSchuster, Karl-FriedrichShao, LijingShen, ZhiqiangSmall, DesSohn, Bong WonSooHoo, JasonTazaki, FumieTiede, PaulTilanus, Remo P. J.Titus, MichaelToma, KenjiTorne, PabloTrent, TylerTraianou, EfthaliaTrippe, SaschaTsuda, Shuichirovan Bemmel, Ilsevan Langevelde, Huib Janvan Rossum, Daniel R.Wagner, JanWardle, JohnWard-Thompson, DerekWex, NorbertWharton, RobertWu, QingwenYoon, DoosooYoung, AndréYoung, KenYounsi, ZiriYuan, FengYuan, Ye-FeiZensus, J. AntonZhao, GuangyaoZhao, Shan-ShanZhu, ZiyanDOI: info:10.3847/1538-4357/abac0dv. 90167
Wielgus, Maciek, Akiyama, Kazunori, Blackburn, Lindy, Chan, Chi-kwan, Dexter, Jason, Doeleman, Sheperd S., Fish, Vincent L., Issaoun, Sara, Johnson, Michael D., Krichbaum, Thomas P., Lu, Ru-Sen, Pesce, Dominic W., Wong, George N., Bower, Geoffrey C., Broderick, Avery E., Chael, Andrew, Chatterjee, Koushik, Gammie, Charles F., Georgiev, Boris, Hada, Kazuhiro, Loinard, Laurent, Markoff, Sera, Marrone, Daniel P., Plambeck, Richard, Weintroub, Jonathan et al. 2020. "Monitoring the Morphology of M87* in 2009-2017 with the Event Horizon Telescope." The Astrophysical Journal 901:67. https://doi.org/10.3847/1538-4357/abac0d
ID: 157688
Type: article
Authors: Wielgus, Maciek; Akiyama, Kazunori; Blackburn, Lindy; Chan, Chi-kwan; Dexter, Jason; Doeleman, Sheperd S.; Fish, Vincent L.; Issaoun, Sara; Johnson, Michael D.; Krichbaum, Thomas P.; Lu, Ru-Sen; Pesce, Dominic W.; Wong, George N.; Bower, Geoffrey C.; Broderick, Avery E.; Chael, Andrew; Chatterjee, Koushik; Gammie, Charles F.; Georgiev, Boris; Hada, Kazuhiro; Loinard, Laurent; Markoff, Sera; Marrone, Daniel P.; Plambeck, Richard; Weintroub, Jonathan; Dexter, Matthew; MacMahon, David H. E.; Wright, Melvyn; Alberdi, Antxon; Alef, Walter; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barausse, Enrico; Barrett, John; Bintley, Dan; Boland, Wilfred; Bouman, Katherine L.; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crew, Geoffrey B.; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafeliciae; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dzib, Sergio A.; Eatough, Ralph P.; Falcke, Heino; Fomalont, Ed; Fraga-Encinas, Raquel; Friberg, Per; Fromm, Christian M.; Galison, Peter; García, Roberto; Gentaz, Olivier; Goddi, Ciriaco; Gold, Roman; Gómez, José L.; Gómez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Inoue, Makoto; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Jorstad, Svetlana; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Jae-Young; Kim, Junhan; Kim, Jongsoo; Kino, Motoki; Koay, Jun Yi; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lico, Rocco; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Lonsdale, Colin; MacDonald, Nicholas R.; Mao, Jirong; Marchili, Nicola; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Yosuke; Mizuno, Izumi; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Müller, Cornelia; Musoke, Gibwa; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C. M.; Park, Jongho; Patel, Nimesh; Pen, Ue-Li; Piétu, Vincent; PopStefanija, Aleksandar; Porth, Oliver; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Ryan, Benjamin R.; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Savolainen, Tuomas; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Tazaki, Fumie; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Trent, Tyler; Traianou, Efthalia; Trippe, Sascha; Tsuda, Shuichiro; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Wardle, John; Ward-Thompson, Derek; Wex, Norbert; Wharton, Robert; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guangyao; Zhao, Shan-Shan; Zhu, Ziyan
Abstract: The Event Horizon Telescope (EHT) has recently delivered the first resolved images of M87*, the supermassive black hole in the center of the M87 galaxy. These images were produced using 230 GHz observations performed in 2017 April. Additional observations are required to investigate the persistence of the primary image feature-a ring with azimuthal brightness asymmetry-and to quantify the image variability on event horizon scales. To address this need, we analyze M87* data collected with prototype EHT arrays in 2009, 2011, 2012, and 2013. While these observations do not contain enough information to produce images, they are sufficient to constrain simple geometric models. We develop a modeling approach based on the framework utilized for the 2017 EHT data analysis and validate our procedures using synthetic data. Applying the same approach to the observational data sets, we find the M87* morphology in 2009-2017 to be consistent with a persistent asymmetric ring of ∼40 μas diameter. The position angle of the peak intensity varies in time. In particular, we find a significant difference between the position angle measured in 2013 and 2017. These variations are in broad agreement with predictions of a subset of general relativistic magnetohydrodynamic simulations. We show that quantifying the variability across multiple observational epochs has the potential to constrain the physical properties of the source, such as the accretion state or the black hole spin.
EHT-HOPS Pipeline for Millimeter VLBI Data ReductionBlackburn, LindyChan, Chi-kwanCrew, Geoffrey B.Fish, Vincent L.Issaoun, SaraJohnson, Michael D.Wielgus, MaciekAkiyama, KazunoriBarrett, JohnBouman, Katherine L.Cappallo, RogerChael, Andrew A.Janssen, MichaelLonsdale, Colin J.Doeleman, Sheperd S.DOI: info:10.3847/1538-4357/ab328dv. 88223
Blackburn, Lindy, Chan, Chi-kwan, Crew, Geoffrey B., Fish, Vincent L., Issaoun, Sara, Johnson, Michael D., Wielgus, Maciek, Akiyama, Kazunori, Barrett, John, Bouman, Katherine L., Cappallo, Roger, Chael, Andrew A., Janssen, Michael, Lonsdale, Colin J., and Doeleman, Sheperd S. 2019. "EHT-HOPS Pipeline for Millimeter VLBI Data Reduction." The Astrophysical Journal 882:23. https://doi.org/10.3847/1538-4357/ab328d
ID: 154402
Type: article
Authors: Blackburn, Lindy; Chan, Chi-kwan; Crew, Geoffrey B.; Fish, Vincent L.; Issaoun, Sara; Johnson, Michael D.; Wielgus, Maciek; Akiyama, Kazunori; Barrett, John; Bouman, Katherine L.; Cappallo, Roger; Chael, Andrew A.; Janssen, Michael; Lonsdale, Colin J.; Doeleman, Sheperd S.
Abstract: We present the design and implementation of an automated data calibration and reduction pipeline for very long baseline interferometric (VLBI) observations taken at millimeter wavelengths. These short radio wavelengths provide the best imaging resolution available from ground-based VLBI networks such as the Event Horizon Telescope (EHT) and the Global Millimeter VLBI Array (GMVA) but require specialized processing owing to the strong effects from atmospheric opacity and turbulence, as well as the heterogeneous nature of existing global arrays. The pipeline builds on a calibration suite (HOPS) originally designed for precision geodetic VLBI. To support the reduction of data for astronomical observations, we have developed an additional framework for global phase and amplitude calibration that provides output in a standard data format for astronomical imaging and analysis. The pipeline was successfully used toward the reduction of 1.3 mm observations from the EHT 2017 campaign, leading to the first image of a black hole "shadow" at the center of the radio galaxy M87. In this work, we analyze observations taken at 3.5 mm (86 GHz) by the GMVA, joined by the phased Atacama Large Millimeter/submillimeter Array in 2017 April, and demonstrate the benefits from the specialized processing of high-frequency VLBI data with respect to classical analysis techniques.
Micro-arcsecond structure of Sagittarius A∗ revealed by high-sensitivity 86 GHz VLBI observationsBrinkerink, Christiaan D.Müller, CorneliaFalcke, Heino D.Issaoun, SaraAkiyama, KazunoriBower, Geoffrey C.Krichbaum, Thomas P.Deller, Adam T.Castillo, EdgarDoeleman, Sheperd S.Fraga-Encinas, RaquelGoddi, CiriacoHernández-Gómez, AntonioHughes, David H.Kramer, MichaelLéon-Tavares, JonathanLoinard, LaurentMontaña, AlfredoMościbrodzka, MonikaOrtiz-León, Gisela N.Sanchez-Arguelles, DavidTilanus, Remo P. J.Wilson, Grant W.Zensus, AntonDOI: info:10.1051/0004-6361/201834148v. 621A119
Brinkerink, Christiaan D., Müller, Cornelia, Falcke, Heino D., Issaoun, Sara, Akiyama, Kazunori, Bower, Geoffrey C., Krichbaum, Thomas P., Deller, Adam T., Castillo, Edgar, Doeleman, Sheperd S., Fraga-Encinas, Raquel, Goddi, Ciriaco, Hernández-Gómez, Antonio, Hughes, David H., Kramer, Michael, Léon-Tavares, Jonathan, Loinard, Laurent, Montaña, Alfredo, Mościbrodzka, Monika, Ortiz-León, Gisela N., Sanchez-Arguelles, David, Tilanus, Remo P. J., Wilson, Grant W., and Zensus, Anton. 2019. "Micro-arcsecond structure of Sagittarius A∗ revealed by high-sensitivity 86 GHz VLBI observations." Astronomy and Astrophysics 621:A119. https://doi.org/10.1051/0004-6361/201834148
ID: 150408
Type: article
Authors: Brinkerink, Christiaan D.; Müller, Cornelia; Falcke, Heino D.; Issaoun, Sara; Akiyama, Kazunori; Bower, Geoffrey C.; Krichbaum, Thomas P.; Deller, Adam T.; Castillo, Edgar; Doeleman, Sheperd S.; Fraga-Encinas, Raquel; Goddi, Ciriaco; Hernández-Gómez, Antonio; Hughes, David H.; Kramer, Michael; Léon-Tavares, Jonathan; Loinard, Laurent; Montaña, Alfredo; Mościbrodzka, Monika; Ortiz-León, Gisela N.; Sanchez-Arguelles, David; Tilanus, Remo P. J.; Wilson, Grant W.; Zensus, Anton
Abstract: Context. The compact radio source Sagittarius A (Sgr A) in the Galactic centre is the primary supermassive black hole candidate. General relativistic magnetohydrodynamical (GRMHD) simulations of the accretion flow around Sgr A predict the presence of sub-structure at observing wavelengths of ˜3 mm and below (frequencies of 86 GHz and above). For very long baseline interferometry (VLBI) observations of Sgr A at this frequency the blurring effect of interstellar scattering becomes sub-dominant, and arrays such as the high sensitivity array (HSA) and the global mm-VLBI array (GMVA) are now capable of resolving potential sub-structure in the source. Such investigations help to improve our understanding of the emission geometry of the mm-wave emission of Sgr A, which is crucial for constraining theoretical models and for providing a background to interpret 1 mm VLBI data from the Event Horizon Telescope (EHT). Aims: Following the closure phase analysis in our first paper, which indicates asymmetry in the 3 mm emission of Sgr A, here we have used the full visibility information to check for possible sub-structure. We extracted source size information from closure amplitude analysis, and investigate how this constrains a combined fit of the size-frequency relation and the scattering law for Sgr A. Methods: We performed high-sensitivity VLBI observations of Sgr A at 3 mm using the Very Long Baseline Array (VLBA) and the Large Millimeter Telescope (LMT) in Mexico on two consecutive days in May 2015, with the second epoch including the Greenbank Telescope (GBT). Results: We confirm the asymmetry for the experiment including GBT. Modelling the emission with an elliptical Gaussian results in significant residual flux of ˜10 mJy in south-eastern direction. The analysis of closure amplitudes allows us to precisely constrain the major and minor axis size of the main emission component. We discuss systematic effects which need to be taken into account. We consider our results in the context of the existing body of size measurements over a range of observing frequencies and investigate how well-constrained the size-frequency relation is by performing a simultaneous fit to the scattering law and the size-frequency relation. Conclusions: We find an overall source geometry that matches previous findings very closely, showing a deviation in fitted model parameters less than 3% over a time scale of weeks and suggesting a highly stable global source geometry over time. The reported sub-structure in the 3 mm emission of Sgr A is consistent with theoretical expectations of refractive noise on long baselines. However, comparing our findings with recent results from 1 mm and 7 mm VLBI observations, which also show evidence for east-west asymmetry, we cannot exclude an intrinsic origin. Confirmation of persistent intrinsic substructure will require further VLBI observations spread out over multiple epochs. The reduced images (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/621/A119
Prospects for Wideband VLBI Correlation in the CloudGill, AjayBlackburn, LindyRoshanineshat, ArashChan, Chi-kwanDoeleman, Sheperd S.Johnson, Michael D.Raymond, Alexander W.Weintroub, JonathanDOI: info:10.1088/1538-3873/ab32a8v. 131124501
Gill, Ajay, Blackburn, Lindy, Roshanineshat, Arash, Chan, Chi-kwan, Doeleman, Sheperd S., Johnson, Michael D., Raymond, Alexander W., and Weintroub, Jonathan. 2019. "Prospects for Wideband VLBI Correlation in the Cloud." Publications of the Astronomical Society of the Pacific 131:124501. https://doi.org/10.1088/1538-3873/ab32a8
ID: 154713
Type: article
Authors: Gill, Ajay; Blackburn, Lindy; Roshanineshat, Arash; Chan, Chi-kwan; Doeleman, Sheperd S.; Johnson, Michael D.; Raymond, Alexander W.; Weintroub, Jonathan
Abstract: This paper proposes a cloud architecture for the correlation of wide bandwidth Very Long Baseline Interferometry (VLBI) data. Cloud correlation facilitates processing of entire experiments in parallel using flexibly allocated and practically unlimited compute resources. This approach offers a potential improvement over dedicated correlation clusters, which are constrained by a fixed number of installed processor nodes and playback units. Additionally, cloud storage offers an alternative to maintaining a fleet of hard disk drives that might be utilized intermittently. Here, we describe benchmarks of VLBI correlation using the DiFX-2.5.2 software on the Google Cloud Platform to assess cloud-based correlation performance. In our analysis, the number of virtual central processing units per virtual machine was varied to determine the optimum configuration of cloud resources. The number of stations was varied to determine the scaling of correlation time with VLBI arrays of different sizes. Data transfer rates from Google cloud storage to the virtual machines performing the correlation were also measured. Based on the results, we present an example cloud correlation configuration. Current cloud service and equipment pricing data is used to compile cost estimates allowing an approximate economic comparison between cloud and cluster processing. We note that the economic comparisons are based on cost figures which are a moving target, and are highly dependent on factors such as the utilization of cluster and media, which are a challenge to estimate. Our model suggests that shifting to the cloud is an alternative path for high data rate, low duty cycle wideband VLBI correlation that should continue to be explored. In the production phase of VLBI correlation, the cloud has the potential to significantly reduce data processing times and allow the processing of more science experiments in a given year for the petabyte- scale data sets increasingly common in both astronomy and geodesy VLBI applications.
The Size, Shape, and Scattering of Sagittarius A* at 86 GHz: First VLBI with ALMAIssaoun, SaraJohnson, Michael D.Blackburn, LindyBrinkerink, C. D.Mościbrodzka, M.Chael, AndrewGoddi, C.Martí-Vidal, I.Wagner, J.Doeleman, Sheperd S.Falcke, H.Krichbaum, T. P.Akiyama, K.Bach, U.Bouman, Katherine L.Bower, G. C.Broderick, A.Cho, I.Crew, G.Dexter, J.Fish, V.Gold, R.Gómez, J. L.Hada, K.Hernández-Gómez, A.Janßen, M.Kino, M.Kramer, M.Loinard, L.Lu, R. -SMarkoff, S.Marrone, D. P.Matthews, L. D.Moran, James M.Müller, C.Roelofs, F.Ros, E.Rottmann, H.Sanchez, S.Tilanus, R. P. J.de Vicente, P.Wielgus, MaciekZensus, J. A.Zhao, G. -YDOI: info:10.3847/1538-4357/aaf732v. 87130
Issaoun, Sara, Johnson, Michael D., Blackburn, Lindy, Brinkerink, C. D., Mościbrodzka, M., Chael, Andrew, Goddi, C., Martí-Vidal, I., Wagner, J., Doeleman, Sheperd S., Falcke, H., Krichbaum, T. P., Akiyama, K., Bach, U., Bouman, Katherine L., Bower, G. C., Broderick, A., Cho, I., Crew, G., Dexter, J., Fish, V., Gold, R., Gómez, J. L., Hada, K., Hernández-Gómez, A. et al. 2019. "The Size, Shape, and Scattering of Sagittarius A* at 86 GHz: First VLBI with ALMA." The Astrophysical Journal 871:30. https://doi.org/10.3847/1538-4357/aaf732
ID: 150431
Type: article
Authors: Issaoun, Sara; Johnson, Michael D.; Blackburn, Lindy; Brinkerink, C. D.; Mościbrodzka, M.; Chael, Andrew; Goddi, C.; Martí-Vidal, I.; Wagner, J.; Doeleman, Sheperd S.; Falcke, H.; Krichbaum, T. P.; Akiyama, K.; Bach, U.; Bouman, Katherine L.; Bower, G. C.; Broderick, A.; Cho, I.; Crew, G.; Dexter, J.; Fish, V.; Gold, R.; Gómez, J. L.; Hada, K.; Hernández-Gómez, A.; Janßen, M.; Kino, M.; Kramer, M.; Loinard, L.; Lu, R. -S; Markoff, S.; Marrone, D. P.; Matthews, L. D.; Moran, James M.; Müller, C.; Roelofs, F.; Ros, E.; Rottmann, H.; Sanchez, S.; Tilanus, R. P. J.; de Vicente, P.; Wielgus, Maciek; Zensus, J. A.; Zhao, G. -Y
Abstract: The Galactic center supermassive black hole Sagittarius A* (Sgr A*) is one of the most promising targets to study the dynamics of black hole accretion and outflow via direct imaging with very long baseline interferometry (VLBI). At 3.5 mm (86 GHz), the emission from Sgr A* is resolvable with the Global Millimeter VLBI Array (GMVA). We present the first observations of Sgr A* with the phased Atacama Large Millimeter/submillimeter Array (ALMA) joining the GMVA. Our observations achieve an angular resolution of ∼87 μas, improving upon previous experiments by a factor of two. We reconstruct a first image of the unscattered source structure of Sgr A* at 3.5 mm, mitigating the effects of interstellar scattering. The unscattered source has a major-axis size of 120 ± 34 μas (12 ± 3.4 Schwarzschild radii) and a symmetrical morphology (axial ratio of {1.2}-0.2+0.3), which is further supported by closure phases consistent with zero within 3σ. We show that multiple disk-dominated models of Sgr A* match our observational constraints, while the two jet-dominated models considered are constrained to small viewing angles. Our long-baseline detections to ALMA also provide new constraints on the scattering of Sgr A*, and we show that refractive scattering effects are likely to be weak for images of Sgr A* at 1.3 mm with the Event Horizon Telescope. Our results provide the most stringent constraints to date for the intrinsic morphology and refractive scattering of Sgr A*, demonstrating the exceptional contribution of ALMA to millimeter VLBI.
Detection of Pulses from the Vela Pulsar at Millimeter Wavelengths with Phased ALMALiu, KuoYoung, AndréWharton, RobertBlackburn, LindyCappallo, RogerChatterjee, ShamiCordes, James M.Crew, Geoffrey B.Desvignes, GregoryDoeleman, Sheperd S.Eatough, Ralph P.Falcke, HeinoGoddi, CiriacoJohnson, Michael D.Johnston, SimonKaruppusamy, RameshKramer, MichaelMatthews, Lynn D.Ransom, Scott M.Rezzolla, LucianoRottmann, HelgeTilanus, Remo P. J.Torne, PabloDOI: info:10.3847/2041-8213/ab4da8v. 885L10
Liu, Kuo, Young, André, Wharton, Robert, Blackburn, Lindy, Cappallo, Roger, Chatterjee, Shami, Cordes, James M., Crew, Geoffrey B., Desvignes, Gregory, Doeleman, Sheperd S., Eatough, Ralph P., Falcke, Heino, Goddi, Ciriaco, Johnson, Michael D., Johnston, Simon, Karuppusamy, Ramesh, Kramer, Michael, Matthews, Lynn D., Ransom, Scott M., Rezzolla, Luciano, Rottmann, Helge, Tilanus, Remo P. J., and Torne, Pablo. 2019. "Detection of Pulses from the Vela Pulsar at Millimeter Wavelengths with Phased ALMA." The Astrophysical Journal 885:L10. https://doi.org/10.3847/2041-8213/ab4da8
ID: 154583
Type: article
Authors: Liu, Kuo; Young, André; Wharton, Robert; Blackburn, Lindy; Cappallo, Roger; Chatterjee, Shami; Cordes, James M.; Crew, Geoffrey B.; Desvignes, Gregory; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Goddi, Ciriaco; Johnson, Michael D.; Johnston, Simon; Karuppusamy, Ramesh; Kramer, Michael; Matthews, Lynn D.; Ransom, Scott M.; Rezzolla, Luciano; Rottmann, Helge; Tilanus, Remo P. J.; Torne, Pablo
Abstract: We report on the first detection of pulsed radio emission from a radio pulsar with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope. The detection was made in the Band-3 frequency range (85-101 GHz) using ALMA in the phased-array mode developed for VLBI observations. A software pipeline has been implemented to enable a regular pulsar observing mode in the future. We describe the pipeline and demonstrate the capability of ALMA to perform pulsar timing and searching. We also measure the flux density and polarization properties of the Vela pulsar (PSR J0835-4510) at millimeter wavelengths, providing the first polarimetric study of any ordinary pulsar at frequencies above 32 GHz. Finally, we discuss the lessons learned from the Vela observations for future pulsar studies with ALMA, particularly for searches near the supermassive black hole in the Galactic center, and the potential of using pulsars for polarization calibration of ALMA.
Metrics and Motivations for Earth-Space VLBI: Time-resolving Sgr A* with the Event Horizon TelescopePalumbo, Daniel C. M.Doeleman, Sheperd S.Johnson, Michael D.Bouman, Katherine L.Chael, Andrew A.DOI: info:10.3847/1538-4357/ab2bedv. 88162
Palumbo, Daniel C. M., Doeleman, Sheperd S., Johnson, Michael D., Bouman, Katherine L., and Chael, Andrew A. 2019. "Metrics and Motivations for Earth-Space VLBI: Time-resolving Sgr A* with the Event Horizon Telescope." The Astrophysical Journal 881:62. https://doi.org/10.3847/1538-4357/ab2bed
ID: 154251
Type: article
Authors: Palumbo, Daniel C. M.; Doeleman, Sheperd S.; Johnson, Michael D.; Bouman, Katherine L.; Chael, Andrew A.
Abstract: Very-long-baseline interferometry (VLBI) at frequencies above 230 GHz with Earth-diameter baselines gives spatial resolution finer than the ̃50 μas "shadow" of the supermassive black hole at the Galactic Center, Sagittarius A* (Sgr A*). Imaging static and dynamical structure near the "shadow" provides a test of general relativity and may allow measurement of black hole parameters. However, traditional Earth-rotation synthesis is inapplicable for sources (such as Sgr A*) with intraday variability. Expansions of ground-based arrays to include space-VLBI stations may enable imaging capability on timescales comparable to the prograde innermost stable circular orbit (ISCO) of Sgr A*, which is predicted to be 4-30 minutes, depending on black hole spin. We examine the basic requirements for space VLBI, and we develop tools for simulating observations with orbiting stations. We also develop a metric to quantify the imaging capabilities of an array irrespective of detailed image morphology or reconstruction method. We validate this metric on example reconstructions of simulations of Sgr A* at 230 and 345 GHz, and use these results to motivate expanding the Event Horizon Telescope to include small dishes in Low Earth Orbit (LEO). We demonstrate that high- sensitivity sites such as the Atacama Large Millimeter/Submillimeter Array (ALMA) make it viable to add small orbiters to existing ground arrays, as space-ALMA baselines would have sensitivity comparable to ground-based non-ALMA baselines. We show that LEO-enhanced arrays sample half of the diffraction-limited Fourier plane of Sgr A* in less than 30 minutes, enabling reconstructions of near-horizon structure with a normalized root-mean-square error ≲0.3 on sub-ISCO timescales.
The Event Horizon General Relativistic Magnetohydrodynamic Code Comparison ProjectPorth, OliverChatterjee, KoushikNarayan, RameshGammie, Charles F.Mizuno, YosukeAnninos, PeterBaker, John G.Bugli, MatteoChan, Chi-kwanDavelaar, JordyDel Zanna, LucaEtienne, Zachariah B.Fragile, P. ChrisKelly, Bernard J.Liska, MatthewMarkoff, SeraMcKinney, Jonathan C.Mishra, BhupendraNoble, Scott C.Olivares, HéctorPrather, BenRezzolla, LucianoRyan, Benjamin R.Stone, James M.Tomei, NiccolòWhite, Christopher J.Younsi, ZiriAkiyama, KazunoriAlberdi, AntxonAlef, WalterAsada, KeiichiAzulay, RebeccaBaczko, Anne-KathrinBall, DavidBaloković, MislavBarrett, JohnBintley, DanBlackburn, LindyBoland, WilfredBouman, Katherine L.Bower, Geoffrey C.Bremer, MichaelBrinkerink, Christiaan D.Brissenden, RogerBritzen, SilkeBroderick, Avery E.Broguiere, DominiqueBronzwaer, ThomasByun, Do-YoungCarlstrom, John E.Chael, AndrewChatterjee, ShamiChen, Ming-TangChen, YongjunCho, IljeChristian, PierreConway, John E.Cordes, James M.GeoffreyCrew, B.Cui, YuzhuDe Laurentis, MariafeliciaDeane, RogerDempsey, JessicaDesvignes, GregoryDoeleman, Sheperd S.Eatough, Ralph P.Falcke, HeinoFish, Vincent L.Fomalont, EdFraga-Encinas, RaquelFreeman, BillFriberg, PerFromm, Christian M.Gómez, José L.Galison, PeterGarcía, RobertoGentaz, OlivierGeorgiev, BorisGoddi, CiriacoGold, RomanGu, MinfengGurwell, MarkHada, KazuhiroHecht, Michael H.Hesper, RonaldHo, Luis C.Ho, PaulHonma, MarekiHuang, Chih-Wei L.Huang, LeiHughes, David H.Ikeda, ShiroInoue, MakotoIssaoun, SaraJames, David J.Jannuzi, Buell T.Janssen, MichaelJeter, BrittonJiang, WuJohnson, Michael D.Jorstad, SvetlanaJung, TaehyunKarami, MansourKaruppusamy, RameshKawashima, TomohisaKeating, Garrett K.Kettenis, MarkKim, Jae-YoungKim, JunhanKim, JongsooKino, MotokiKoay, Jun YiPatrickKoch, M.Koyama, ShokoKramer, MichaelKramer, CarstenKrichbaum, Thomas P.Kuo, Cheng-YuLauer, Tod R.Lee, Sang-SungLi, Yan-RongLi, ZhiyuanLindqvist, MichaelLiu, KuoLiuzzo, ElisabettaLo, Wen-PingLobanov, Andrei P.Loinard, LaurentLonsdale, ColinLu, Ru-SenMacDonald, Nicholas R.Mao, JirongMarrone, Daniel P.Marscher, Alan P.Martí-Vidal, IvánMatsushita, SatokiMatthews, Lynn D.Medeiros, LiaMenten, Karl M.Mizuno, IzumiMoran, James M.Moriyama, KotaroMoscibrodzka, MonikaMüller, CorneliaNagai, HiroshiNagar, Neil M.Nakamura, MasanoriNarayanan, GopalNatarajan, IniyanNeri, RobertoNi, ChunchongNoutsos, AristeidisOkino, HirokiOyama, TomoakiÖzel, FeryalPalumbo, Daniel C. M.Patel, NimeshPen, Ue-LiPesce, Dominic W.Piétu, VincentPlambeck, RichardPopStefanija, AleksandarPreciado-López, Jorge A.Psaltis, DimitriosPu, Hung-YiRamakrishnan, VenkatesshRao, RamprasadRawlings, Mark G.Raymond, Alexander W.Ripperda, BartRoelofs, FreekRogers, AlanRos, EduardoRose, MelRoshanineshat, ArashRottmann, HelgeRoy, Alan L.Ruszczyk, ChetRygl, Kazi L. J.Sánchez, SalvadorSánchez-Arguelles, DavidSasada, MahitoSavolainen, TuomasSchloerb, F. PeterSchuster, Karl-FriedrichShao, LijingShen, ZhiqiangSmall, DesSohn, Bong WonSooHoo, JasonTazaki, FumieTiede, PaulTilanus, Remo P. J.Titus, MichaelToma, KenjiTorne, PabloTrent, TylerTrippe, SaschaTsuda, Shuichirovan Bemmel, Ilsevan Langevelde, Huib Janvan Rossum, Daniel R.Wagner, JanWardle, JohnWeintroub, JonathanWex, NorbertWharton, RobertWielgus, MaciekWong, George N.Wu, QingwenYoung, KenYoung, AndréYuan, FengYuan, Ye-FeiZensus, J. AntonZhao, GuangyaoZhao, Shan-ShanZhu, ZiyanEvent Horizon Telescope CollaborationDOI: info:10.3847/1538-4365/ab29fdv. 24326
Porth, Oliver, Chatterjee, Koushik, Narayan, Ramesh, Gammie, Charles F., Mizuno, Yosuke, Anninos, Peter, Baker, John G., Bugli, Matteo, Chan, Chi-kwan, Davelaar, Jordy, Del Zanna, Luca, Etienne, Zachariah B., Fragile, P. Chris, Kelly, Bernard J., Liska, Matthew, Markoff, Sera, McKinney, Jonathan C., Mishra, Bhupendra, Noble, Scott C., Olivares, Héctor, Prather, Ben, Rezzolla, Luciano, Ryan, Benjamin R., Stone, James M., Tomei, Niccolò et al. 2019. "The Event Horizon General Relativistic Magnetohydrodynamic Code Comparison Project." The Astrophysical Journal Supplement Series 243:26. https://doi.org/10.3847/1538-4365/ab29fd
ID: 154281
Type: article
Authors: Porth, Oliver; Chatterjee, Koushik; Narayan, Ramesh; Gammie, Charles F.; Mizuno, Yosuke; Anninos, Peter; Baker, John G.; Bugli, Matteo; Chan, Chi-kwan; Davelaar, Jordy; Del Zanna, Luca; Etienne, Zachariah B.; Fragile, P. Chris; Kelly, Bernard J.; Liska, Matthew; Markoff, Sera; McKinney, Jonathan C.; Mishra, Bhupendra; Noble, Scott C.; Olivares, Héctor; Prather, Ben; Rezzolla, Luciano; Ryan, Benjamin R.; Stone, James M.; Tomei, Niccolò; White, Christopher J.; Younsi, Ziri; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barrett, John; Bintley, Dan; Blackburn, Lindy; Boland, Wilfred; Bouman, Katherine L.; Bower, Geoffrey C.; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chael, Andrew; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Geoffrey; Crew, B.; Cui, Yuzhu; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Fish, Vincent L.; Fomalont, Ed; Fraga-Encinas, Raquel; Freeman, Bill; Friberg, Per; Fromm, Christian M.; Gómez, José L.; Galison, Peter; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Johnson, Michael D.; Jorstad, Svetlana; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Jae-Young; Kim, Junhan; Kim, Jongsoo; Kino, Motoki; Koay, Jun Yi; Patrick; Koch, M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Krichbaum, Thomas P.; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Marrone, Daniel P.; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Izumi; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Müller, Cornelia; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayanan, Gopal; Natarajan, Iniyan; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Okino, Hiroki; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C. M.; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Savolainen, Tuomas; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Tazaki, Fumie; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Trent, Tyler; Trippe, Sascha; Tsuda, Shuichiro; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wielgus, Maciek; Wong, George N.; Wu, Qingwen; Young, Ken; Young, André; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guangyao; Zhao, Shan-Shan; Zhu, Ziyan; Event Horizon Telescope Collaboration
Abstract: Recent developments in compact object astrophysics, especially the discovery of merging neutron stars by LIGO, the imaging of the black hole in M87 by the Event Horizon Telescope, and high- precision astrometry of the Galactic Center at close to the event horizon scale by the GRAVITY experiment motivate the development of numerical source models that solve the equations of general relativistic magnetohydrodynamics (GRMHD). Here we compare GRMHD solutions for the evolution of a magnetized accretion flow where turbulence is promoted by the magnetorotational instability from a set of nine GRMHD codes: Athena++, BHAC, Cosmos++, ECHO, H-AMR, iharm3D, HARM-Noble, IllinoisGRMHD, and KORAL. Agreement among the codes improves as resolution increases, as measured by a consistently applied, specially developed set of code performance metrics. We conclude that the community of GRMHD codes is mature, capable, and consistent on these test problems.
ALMA Polarimetry of Sgr A*: Probing the Accretion Flow from the Event Horizon to the Bondi RadiusBower, Geoffrey C.Broderick, AveryDexter, JasonDoeleman, ShepherdFalcke, HeinoFish, VincentJohnson, Michael D.Marrone, Daniel P.Moran, James M.Moscibrodzka, MonikaPeck, AlisonPlambeck, Richard L.Rao, RamprasadDOI: info:10.3847/1538-4357/aae983v. 868101
Bower, Geoffrey C., Broderick, Avery, Dexter, Jason, Doeleman, Shepherd, Falcke, Heino, Fish, Vincent, Johnson, Michael D., Marrone, Daniel P., Moran, James M., Moscibrodzka, Monika, Peck, Alison, Plambeck, Richard L., and Rao, Ramprasad. 2018. "ALMA Polarimetry of Sgr A*: Probing the Accretion Flow from the Event Horizon to the Bondi Radius." The Astrophysical Journal 868:101. https://doi.org/10.3847/1538-4357/aae983
ID: 150178
Type: article
Authors: Bower, Geoffrey C.; Broderick, Avery; Dexter, Jason; Doeleman, Shepherd; Falcke, Heino; Fish, Vincent; Johnson, Michael D.; Marrone, Daniel P.; Moran, James M.; Moscibrodzka, Monika; Peck, Alison; Plambeck, Richard L.; Rao, Ramprasad
Abstract: Millimeter polarimetry of Sgr A* probes the linearly polarized emission region on a scale of ∼10 Schwarzschild radii (R S ), as well as the dense, magnetized accretion flow on scales out to the Bondi radius (∼105 R S ) through Faraday rotation. We present here multi-epoch ALMA Band 6 (230 GHz) polarimetry of Sgr A*. The results confirm a mean rotation measure, {RM}≈ -5× {10}5 {rad} {{{m}}}-2, consistent with measurements over the past 20 yr, and support an interpretation of the RM as originating from a radiatively inefficient accretion flow with \dot{M}≈ {10}-8 {M}ȯ {yr}}-1. Variability is observed for the first time in the RM on timescales that range from hours to months. The long-term variations may be the result of changes in the line-of-sight properties in a turbulent accretion flow. Short-term variations in the apparent RM are not necessarily the result of Faraday rotation and may be the result of complex emission and propagatation effects close to the black hole, some of which have been predicted in numerical modeling. We also confirm the detection of circular polarization at a mean value of ‑1.1% ± 0.2%. It is variable in amplitude on timescales from hours to months, but the handedness remains unchanged from that observed in past centimeter- and millimeter-wavelength detections. These results provide critical constraints for the analysis and interpretation of Event Horizon Telescope data of Sgr A*, M87, and similar sources.
The 1.4 mm Core of Centaurus A: First VLBI Results with the South Pole TelescopeKim, JunhanMarrone, Daniel P.Roy, Alan L.Wagner, JanAsada, KeiichiBeaudoin, ChristopherBlanchard, JayCarlstrom, John E.Chen, Ming-TangCrawford, Thomas M.Crew, Geoffrey B.Doeleman, Sheperd S.Fish, Vincent L.Greer, Christopher H.Gurwell, Mark A.Henning, Jason W.Inoue, MakotoKeisler, RyanKrichbaum, Thomas P.Lu, Ru-SenMuders, DirkMüller, CorneliaNguyen, Chi H.Ros, EduardoSooHoo, JasonTilanus, Remo P. J.Titus, MichaelVertatschitsch, LauraWeintroub, JonathanZensus, J. AntonDOI: info:10.3847/1538-4357/aac7c6v. 861129
Kim, Junhan, Marrone, Daniel P., Roy, Alan L., Wagner, Jan, Asada, Keiichi, Beaudoin, Christopher, Blanchard, Jay, Carlstrom, John E., Chen, Ming-Tang, Crawford, Thomas M., Crew, Geoffrey B., Doeleman, Sheperd S., Fish, Vincent L., Greer, Christopher H., Gurwell, Mark A., Henning, Jason W., Inoue, Makoto, Keisler, Ryan, Krichbaum, Thomas P., Lu, Ru-Sen, Muders, Dirk, Müller, Cornelia, Nguyen, Chi H., Ros, Eduardo, SooHoo, Jason et al. 2018. "The 1.4 mm Core of Centaurus A: First VLBI Results with the South Pole Telescope." The Astrophysical Journal 861:129. https://doi.org/10.3847/1538-4357/aac7c6
ID: 147911
Type: article
Authors: Kim, Junhan; Marrone, Daniel P.; Roy, Alan L.; Wagner, Jan; Asada, Keiichi; Beaudoin, Christopher; Blanchard, Jay; Carlstrom, John E.; Chen, Ming-Tang; Crawford, Thomas M.; Crew, Geoffrey B.; Doeleman, Sheperd S.; Fish, Vincent L.; Greer, Christopher H.; Gurwell, Mark A.; Henning, Jason W.; Inoue, Makoto; Keisler, Ryan; Krichbaum, Thomas P.; Lu, Ru-Sen; Muders, Dirk; Müller, Cornelia; Nguyen, Chi H.; Ros, Eduardo; SooHoo, Jason; Tilanus, Remo P. J.; Titus, Michael; Vertatschitsch, Laura; Weintroub, Jonathan; Zensus, J. Anton
Abstract: Centaurus A (Cen A) is a bright radio source associated with the nearby galaxy NGC 5128 where high-resolution radio observations can probe the jet at scales of less than a light day. The South Pole Telescope (SPT) and the Atacama Pathfinder Experiment performed a single-baseline very-long-baseline interferometry (VLBI) observation of Cen A in 2015 January as part of VLBI receiver deployment for the SPT. We measure the correlated flux density of Cen A at a wavelength of 1.4 mm on a ~7000 km (5 Glambda) baseline. Ascribing this correlated flux density to the core, and with the use of a contemporaneous short-baseline flux density from a Submillimeter Array observation, we infer a core brightness temperature of 1.4 × 1011 K. This is close to the equipartition brightness temperature, where the magnetic and relativistic particle energy densities are equal. Under the assumption of a circular Gaussian core component, we derive an upper limit to the core size varphi = 34.0 ± 1.8 muas, corresponding to 120 Schwarzschild radii for a black hole mass of 5.5 × 107 M &sun;.