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Kinematic Analysis of a Protostellar Multiple System: Measuring the Protostar Masses and Assessing Gravitational Instability in the Disks of L1448 IRS3B and L1448 IRS3AReynolds, Nickalas K.Tobin, John J.Sheehan, PatrickSadavoy, Sarah I.Kratter, Kaitlin M.Li, Zhi-YunChandler, Claire J.Segura-Cox, DominiqueLooney, Leslie W.Dunham, Michael M.DOI: info:10.3847/2041-8213/abcc02v. 907L10
Reynolds, Nickalas K., Tobin, John J., Sheehan, Patrick, Sadavoy, Sarah I., Kratter, Kaitlin M., Li, Zhi-Yun, Chandler, Claire J., Segura-Cox, Dominique, Looney, Leslie W., and Dunham, Michael M. 2021. "Kinematic Analysis of a Protostellar Multiple System: Measuring the Protostar Masses and Assessing Gravitational Instability in the Disks of L1448 IRS3B and L1448 IRS3A." The Astrophysical Journal 907:L10. https://doi.org/10.3847/2041-8213/abcc02
ID: 159349
Type: article
Authors: Reynolds, Nickalas K.; Tobin, John J.; Sheehan, Patrick; Sadavoy, Sarah I.; Kratter, Kaitlin M.; Li, Zhi-Yun; Chandler, Claire J.; Segura-Cox, Dominique; Looney, Leslie W.; Dunham, Michael M.
Abstract: We present new Atacama Large Millimeter/submillimeter Array observations toward a compact (∼230 au separation) triple protostar system, L1448 IRS3B, at 879 μm with 0"11 × 0"05 resolution. Spiral arm structure within the circum-multiple disk is well resolved in dust continuum toward IRS3B, and we detect the known wide (∼2300 au) companion, IRS3A, also resolving possible spiral substructure. Using dense gas tracers, C17O (J = 3 $\to $ 2), H13CO+ (J = 4 $\to $ 3), and H13CN (J = 4 $\to $ 3), we resolve the Keplerian rotation for both the circum-triple disk in IRS3B and the disk around IRS3A. Furthermore, we use the molecular line kinematic data and radiative transfer modeling of the molecular line emission to confirm that the disks are in Keplerian rotation with fitted masses of ${1.19}_{-0.07}^{+0.13}$ M⊙ for IRS3B-ab and ${1.51}_{-0.07}^{+0.06}$ M⊙ for IRS3A and place an upper limit on the central protostar mass for the tertiary IRS3B-c of 0.2 M⊙. We measure the mass of the fragmenting disk of IRS3B to be ∼0.29 M⊙ from the dust continuum emission of the circum-multiple disk and estimate the mass of the clump surrounding IRS3B-c to be 0.07 M⊙. We also find that the disk around IRS3A has a mass of ∼0.04 M⊙. By analyzing the Toomre Q parameter, we find the IRS3A circumstellar disk is gravitationally stable (Q > 5), while the IRS3B disk is consistent with a gravitationally unstable disk (Q < 1) between the radii ∼200-500 au. This coincides with the location of the spiral arms and the tertiary companion IRS3B-c, supporting the hypothesis that IRS3B-c was formed in situ via fragmentation of a gravitationally unstable disk.
Type: article
Authors: Reynolds, Nickalas K.; Tobin, John J.; Sheehan, Patrick; Sadavoy, Sarah I.; Kratter, Kaitlin M.; Li, Zhi-Yun; Chandler, Claire J.; Segura-Cox, Dominique; Looney, Leslie W.; Dunham, Michael M.
Abstract: We present new Atacama Large Millimeter/submillimeter Array observations toward a compact (∼230 au separation) triple protostar system, L1448 IRS3B, at 879 μm with 0"11 × 0"05 resolution. Spiral arm structure within the circum-multiple disk is well resolved in dust continuum toward IRS3B, and we detect the known wide (∼2300 au) companion, IRS3A, also resolving possible spiral substructure. Using dense gas tracers, C17O (J = 3 $\to $ 2), H13CO+ (J = 4 $\to $ 3), and H13CN (J = 4 $\to $ 3), we resolve the Keplerian rotation for both the circum-triple disk in IRS3B and the disk around IRS3A. Furthermore, we use the molecular line kinematic data and radiative transfer modeling of the molecular line emission to confirm that the disks are in Keplerian rotation with fitted masses of ${1.19}_{-0.07}^{+0.13}$ M⊙ for IRS3B-ab and ${1.51}_{-0.07}^{+0.06}$ M⊙ for IRS3A and place an upper limit on the central protostar mass for the tertiary IRS3B-c of 0.2 M⊙. We measure the mass of the fragmenting disk of IRS3B to be ∼0.29 M⊙ from the dust continuum emission of the circum-multiple disk and estimate the mass of the clump surrounding IRS3B-c to be 0.07 M⊙. We also find that the disk around IRS3A has a mass of ∼0.04 M⊙. By analyzing the Toomre Q parameter, we find the IRS3A circumstellar disk is gravitationally stable (Q > 5), while the IRS3B disk is consistent with a gravitationally unstable disk (Q < 1) between the radii ∼200-500 au. This coincides with the location of the spiral arms and the tertiary companion IRS3B-c, supporting the hypothesis that IRS3B-c was formed in situ via fragmentation of a gravitationally unstable disk.
Confirmation of Enhanced Long-wavelength Dust Emission in OMC 2/3Mason, BrianDicker, SimonSadavoy, SarahStanchfield, SaraMroczkowski, TonyRomero, CharlesFriesen, RachelSarazin, CraigSievers, JonathanStanke, ThomasDevlin, MarkDOI: info:10.3847/1538-4357/ab734av. 89313
Mason, Brian, Dicker, Simon, Sadavoy, Sarah, Stanchfield, Sara, Mroczkowski, Tony, Romero, Charles, Friesen, Rachel, Sarazin, Craig, Sievers, Jonathan, Stanke, Thomas, and Devlin, Mark. 2020. "Confirmation of Enhanced Long-wavelength Dust Emission in OMC 2/3." The Astrophysical Journal 893:13. https://doi.org/10.3847/1538-4357/ab734a
ID: 157851
Type: article
Authors: Mason, Brian; Dicker, Simon; Sadavoy, Sarah; Stanchfield, Sara; Mroczkowski, Tony; Romero, Charles; Friesen, Rachel; Sarazin, Craig; Sievers, Jonathan; Stanke, Thomas; Devlin, Mark
Abstract: Previous continuum observations from the MUSTANG camera on the Green Bank Telescope (GBT) of the nearby star-forming filament OMC 2/3 found elevated emission at 3.3 mm relative to shorter-wavelength data. As a consequence, the inferred dust emissivity index obtained from modified blackbody dust spectra was considerably lower than what is typically measured on ∼0.1 pc scales in nearby molecular clouds. Here we present new observations of OMC 2/3 collected with the MUSTANG-2 camera on the GBT that confirm this elevated emission. We also present for the first time sensitive 1 cm observations made with the Ka-band receiver on the GBT, which also show higher than expected emission. We use these observations - along with Herschel, JCMT, Mambo, and GISMO data - to assemble spectral energy distributions (SEDs) of a variety of structures in OMC 2/3 spanning the range 160 μm to 1 cm. The data at 2 mm and shorter are generally consistent with a modified blackbody spectrum and a single value of β ∼ 1.6. The 3 mm and 1 cm data, however, lie well above such an SED. The spectrum of the long-wavelength excess is inconsistent with both free-free emission and standard "Spinning Dust" models for Anomalous Microwave Emission (AME). The 3 mm and 1 cm data could be explained by a flatter dust emissivity at wavelengths shorter than 2 mm, potentially in concert with AME in some regions.
Type: article
Authors: Mason, Brian; Dicker, Simon; Sadavoy, Sarah; Stanchfield, Sara; Mroczkowski, Tony; Romero, Charles; Friesen, Rachel; Sarazin, Craig; Sievers, Jonathan; Stanke, Thomas; Devlin, Mark
Abstract: Previous continuum observations from the MUSTANG camera on the Green Bank Telescope (GBT) of the nearby star-forming filament OMC 2/3 found elevated emission at 3.3 mm relative to shorter-wavelength data. As a consequence, the inferred dust emissivity index obtained from modified blackbody dust spectra was considerably lower than what is typically measured on ∼0.1 pc scales in nearby molecular clouds. Here we present new observations of OMC 2/3 collected with the MUSTANG-2 camera on the GBT that confirm this elevated emission. We also present for the first time sensitive 1 cm observations made with the Ka-band receiver on the GBT, which also show higher than expected emission. We use these observations - along with Herschel, JCMT, Mambo, and GISMO data - to assemble spectral energy distributions (SEDs) of a variety of structures in OMC 2/3 spanning the range 160 μm to 1 cm. The data at 2 mm and shorter are generally consistent with a modified blackbody spectrum and a single value of β ∼ 1.6. The 3 mm and 1 cm data, however, lie well above such an SED. The spectrum of the long-wavelength excess is inconsistent with both free-free emission and standard "Spinning Dust" models for Anomalous Microwave Emission (AME). The 3 mm and 1 cm data could be explained by a flatter dust emissivity at wavelengths shorter than 2 mm, potentially in concert with AME in some regions.
Zooming in on Individual Star Formation: Low- and High-Mass StarsRosen, Anna L.Offner, Stella S. R.Sadavoy, Sarah I.Bhandare, AsmitaVázquez-Semadeni, EnriqueGinsburg, AdamDOI: info:10.1007/s11214-020-00688-5v. 21662
Rosen, Anna L., Offner, Stella S. R., Sadavoy, Sarah I., Bhandare, Asmita, Vázquez-Semadeni, Enrique, and Ginsburg, Adam. 2020. "Zooming in on Individual Star Formation: Low- and High-Mass Stars." Space Science Reviews 216:62. https://doi.org/10.1007/s11214-020-00688-5
ID: 157686
Type: article
Authors: Rosen, Anna L.; Offner, Stella S. R.; Sadavoy, Sarah I.; Bhandare, Asmita; Vázquez-Semadeni, Enrique; Ginsburg, Adam
Abstract: Star formation is a multi-scale, multi-physics problem ranging from the size scale of molecular clouds (∼10 s pc) down to the size scales of dense prestellar cores (∼0.1 pc) that are the birth sites of stars. Several physical processes like turbulence, magnetic fields and stellar feedback, such as radiation pressure and outflows, are more or less important for different stellar masses and size scales. During the last decade a variety of technological and computing advances have transformed our understanding of star formation through the use of multi-wavelength observations, large scale observational surveys, and multi-physics multi-dimensional numerical simulations. Additionally, the use of synthetic observations of simulations have provided a useful tool to interpret observational data and evaluate the importance of various physical processes on different scales in star formation. Here, we review these recent advancements in both high- (M ≳8 M☉) and low-mass star formation.
Type: article
Authors: Rosen, Anna L.; Offner, Stella S. R.; Sadavoy, Sarah I.; Bhandare, Asmita; Vázquez-Semadeni, Enrique; Ginsburg, Adam
Abstract: Star formation is a multi-scale, multi-physics problem ranging from the size scale of molecular clouds (∼10 s pc) down to the size scales of dense prestellar cores (∼0.1 pc) that are the birth sites of stars. Several physical processes like turbulence, magnetic fields and stellar feedback, such as radiation pressure and outflows, are more or less important for different stellar masses and size scales. During the last decade a variety of technological and computing advances have transformed our understanding of star formation through the use of multi-wavelength observations, large scale observational surveys, and multi-physics multi-dimensional numerical simulations. Additionally, the use of synthetic observations of simulations have provided a useful tool to interpret observational data and evaluate the importance of various physical processes on different scales in star formation. Here, we review these recent advancements in both high- (M ≳8 M☉) and low-mass star formation.
The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. II. A Statistical Characterization of Class 0 and Class I Protostellar DisksTobin, John J.Sheehan, Patrick D.Megeath, S. ThomasDíaz-Rodríguez, Ana KarlaOffner, Stella S. R.Murillo, Nadia M.van 't Hoff, Merel L. R.van Dishoeck, Ewine F.Osorio, MayraAnglada, GuillemFurlan, EliseStutz, Amelia M.Reynolds, NickalasKarnath, NicoleFischer, William J.Persson, MagnusLooney, Leslie W.Li, Zhi-YunStephens, IanChandler, Claire J.Cox, ErinDunham, Michael M.Tychoniec, ŁukaszKama, MihkelKratter, KaitlinKounkel, MarinaMazur, BrianMaud, LukePatel, LisaPerez, LauraSadavoy, Sarah I.Segura-Cox, DominiqueSharma, RajeebStephenson, BrianWatson, Dan M.Wyrowski, FriedrichDOI: info:10.3847/1538-4357/ab6f64v. 890130
Tobin, John J., Sheehan, Patrick D., Megeath, S. Thomas, Díaz-Rodríguez, Ana Karla, Offner, Stella S. R., Murillo, Nadia M., van 't Hoff, Merel L. R., van Dishoeck, Ewine F., Osorio, Mayra, Anglada, Guillem, Furlan, Elise, Stutz, Amelia M., Reynolds, Nickalas, Karnath, Nicole, Fischer, William J., Persson, Magnus, Looney, Leslie W., Li, Zhi-Yun, Stephens, Ian, Chandler, Claire J., Cox, Erin, Dunham, Michael M., Tychoniec, Łukasz, Kama, Mihkel, Kratter, Kaitlin et al. 2020. "The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. II. A Statistical Characterization of Class 0 and Class I Protostellar Disks." The Astrophysical Journal 890:130. https://doi.org/10.3847/1538-4357/ab6f64
ID: 156217
Type: article
Authors: Tobin, John J.; Sheehan, Patrick D.; Megeath, S. Thomas; Díaz-Rodríguez, Ana Karla; Offner, Stella S. R.; Murillo, Nadia M.; van 't Hoff, Merel L. R.; van Dishoeck, Ewine F.; Osorio, Mayra; Anglada, Guillem; Furlan, Elise; Stutz, Amelia M.; Reynolds, Nickalas; Karnath, Nicole; Fischer, William J.; Persson, Magnus; Looney, Leslie W.; Li, Zhi-Yun; Stephens, Ian; Chandler, Claire J.; Cox, Erin; Dunham, Michael M.; Tychoniec, Łukasz; Kama, Mihkel; Kratter, Kaitlin; Kounkel, Marina; Mazur, Brian; Maud, Luke; Patel, Lisa; Perez, Laura; Sadavoy, Sarah I.; Segura-Cox, Dominique; Sharma, Rajeeb; Stephenson, Brian; Watson, Dan M.; Wyrowski, Friedrich
Abstract: We have conducted a survey of 328 protostars in the Orion molecular clouds with the Atacama Large Millimeter/submillimeter Array at 0.87 mm at a resolution of ∼0"1 (40 au), including observations with the Very Large Array at 9 mm toward 148 protostars at a resolution of ∼0"08 (32 au). This is the largest multiwavelength survey of protostars at this resolution by an order of magnitude. We use the dust continuum emission at 0.87 and 9 mm to measure the dust disk radii and masses toward the Class 0, Class I, and flat-spectrum protostars, characterizing the evolution of these disk properties in the protostellar phase. The mean dust disk radii for the Class 0, Class I, and flat-spectrum protostars are ${44.9}_{-3.4}^{+5.8}$ , ${37.0}_{-3.0}^{+4.9}$ , and ${28.5}_{-2.3}^{+3.7}$ au, respectively, and the mean protostellar dust disk masses are 25.9 ${}_{-4.0}^{+7.7}$ , ${14.9}_{-2.2}^{+3.8}$ , ${11.6}_{-1.9}^{+3.5}$ ${M}_{\oplus }$ , respectively. The decrease in dust disk masses is expected from disk evolution and accretion, but the decrease in disk radii may point to the initial conditions of star formation not leading to the systematic growth of disk radii or that radial drift is keeping the dust disk sizes small. At least 146 protostellar disks (35% of 379 detected 0.87 mm continuum sources plus 42 nondetections) have disk radii greater than 50 au in our sample. These properties are not found to vary significantly between different regions within Orion. The protostellar dust disk mass distributions are systematically larger than those of Class II disks by a factor of >4, providing evidence that the cores of giant planets may need to at least begin their formation during the protostellar phase.
Type: article
Authors: Tobin, John J.; Sheehan, Patrick D.; Megeath, S. Thomas; Díaz-Rodríguez, Ana Karla; Offner, Stella S. R.; Murillo, Nadia M.; van 't Hoff, Merel L. R.; van Dishoeck, Ewine F.; Osorio, Mayra; Anglada, Guillem; Furlan, Elise; Stutz, Amelia M.; Reynolds, Nickalas; Karnath, Nicole; Fischer, William J.; Persson, Magnus; Looney, Leslie W.; Li, Zhi-Yun; Stephens, Ian; Chandler, Claire J.; Cox, Erin; Dunham, Michael M.; Tychoniec, Łukasz; Kama, Mihkel; Kratter, Kaitlin; Kounkel, Marina; Mazur, Brian; Maud, Luke; Patel, Lisa; Perez, Laura; Sadavoy, Sarah I.; Segura-Cox, Dominique; Sharma, Rajeeb; Stephenson, Brian; Watson, Dan M.; Wyrowski, Friedrich
Abstract: We have conducted a survey of 328 protostars in the Orion molecular clouds with the Atacama Large Millimeter/submillimeter Array at 0.87 mm at a resolution of ∼0"1 (40 au), including observations with the Very Large Array at 9 mm toward 148 protostars at a resolution of ∼0"08 (32 au). This is the largest multiwavelength survey of protostars at this resolution by an order of magnitude. We use the dust continuum emission at 0.87 and 9 mm to measure the dust disk radii and masses toward the Class 0, Class I, and flat-spectrum protostars, characterizing the evolution of these disk properties in the protostellar phase. The mean dust disk radii for the Class 0, Class I, and flat-spectrum protostars are ${44.9}_{-3.4}^{+5.8}$ , ${37.0}_{-3.0}^{+4.9}$ , and ${28.5}_{-2.3}^{+3.7}$ au, respectively, and the mean protostellar dust disk masses are 25.9 ${}_{-4.0}^{+7.7}$ , ${14.9}_{-2.2}^{+3.8}$ , ${11.6}_{-1.9}^{+3.5}$ ${M}_{\oplus }$ , respectively. The decrease in dust disk masses is expected from disk evolution and accretion, but the decrease in disk radii may point to the initial conditions of star formation not leading to the systematic growth of disk radii or that radial drift is keeping the dust disk sizes small. At least 146 protostellar disks (35% of 379 detected 0.87 mm continuum sources plus 42 nondetections) have disk radii greater than 50 au in our sample. These properties are not found to vary significantly between different regions within Orion. The protostellar dust disk mass distributions are systematically larger than those of Class II disks by a factor of >4, providing evidence that the cores of giant planets may need to at least begin their formation during the protostellar phase.
The JCMT BISTRO Survey: The Magnetic Field of the Barnard 1 Star-forming RegionCoudé, SimonBastien, PierreHoude, MartinSadavoy, SarahFriesen, Racheldi Francesco, JamesJohnstone, DougMairs, SteveHasegawa, TetsuoKwon, WoojinLai, Shih-PingQiu, KepingWard-Thompson, DerekBerry, DavidChen, Michael Chun-YuanFiege, JasonFranzmann, EricaHatchell, JenniferLacaille, KevinMatthews, Brenda C.Moriarty-Schieven, Gerald H.Pon, AndyAndré, PhilippeArzoumanian, DorisAso, YusukeByun, Do-YoungEswaraiah, ChakaliChen, Huei-RuChen, Wen PingChing, Tao-ChungCho, JungyeonChoi, MinhoChrysostomou, AntonioChung, Eun JungDoi, YasuoDrabek-Maunder, EmilyDowell, C. DarrenEyres, Stewart P. S.Falle, SamFriberg, PerFuller, GaryFuruya, Ray S.Gledhill, TimGraves, Sarah F.Greaves, Jane S.Griffin, Matt J.Gu, QilaoHayashi, Saeko S.Hoang, ThiemHolland, WayneInoue, TsuyoshiInutsuka, Shu-ichiroIwasaki, KazunariJeong, Il-GyoKanamori, YoshihiroKataoka, AkimasaKang, Ji-hyunKang, MijuKang, Sung-juKawabata, Koji S.Kemper, FranciscaKim, GwanjeongKim, JongsooKim, Kee-TaeKim, Kyoung HeeKim, Mi-RyangKim, ShinyoungKirk, Jason M.Kobayashi, Masato I. N.Koch, Patrick M.Kwon, JungmiLee, Jeong-EunLee, Chang WonLee, Sang-SungLi, DaleiLi, DiLi, Hua-BaiLiu, Hong-LiLiu, JunhaoLiu, Sheng-YuanLiu, TieVan Loo, SvenLyo, A. -RanMatsumura, MasafumiNagata, TetsuyaNakamura, FumitakaNakanishi, HiroyukiOhashi, NagayoshiOnaka, TakashiParsons, HarrietPattle, KatePeretto, NicolasPyo, Tae-SooQian, LeiRao, RamprasadRawlings, Mark G.Retter, BrendanRicher, JohnRigby, AndrewRobitaille, Jean-FrançoisSaito, HiroSavini, GiorgioScaife, Anna M. M.Seta, MasumichiShinnaga, HirokoSoam, ArchanaTamura, MotohideTang, Ya-WenTomisaka, KohjiTsukamoto, YusukeWang, HongchiWang, Jia-WeiWhitworth, Anthony P.Yen, Hsi-WeiYoo, HyunjuYuan, JinghuaZenko, TetsuyaZhang, Chuan-PengZhang, GuoyinZhou, JianjunZhu, LeiThe B-fields In STar-forming Regions Observations (BISTRO CollaborationDOI: info:10.3847/1538-4357/ab1b23v. 87788
Coudé, Simon, Bastien, Pierre, Houde, Martin, Sadavoy, Sarah, Friesen, Rachel, di Francesco, James, Johnstone, Doug, Mairs, Steve, Hasegawa, Tetsuo, Kwon, Woojin, Lai, Shih-Ping, Qiu, Keping, Ward-Thompson, Derek, Berry, David, Chen, Michael Chun-Yuan, Fiege, Jason, Franzmann, Erica, Hatchell, Jennifer, Lacaille, Kevin, Matthews, Brenda C., Moriarty-Schieven, Gerald H., Pon, Andy, André, Philippe, Arzoumanian, Doris, Aso, Yusuke et al. 2019. "The JCMT BISTRO Survey: The Magnetic Field of the Barnard 1 Star-forming Region." The Astrophysical Journal 877:88. https://doi.org/10.3847/1538-4357/ab1b23
ID: 152904
Type: article
Authors: Coudé, Simon; Bastien, Pierre; Houde, Martin; Sadavoy, Sarah; Friesen, Rachel; di Francesco, James; Johnstone, Doug; Mairs, Steve; Hasegawa, Tetsuo; Kwon, Woojin; Lai, Shih-Ping; Qiu, Keping; Ward-Thompson, Derek; Berry, David; Chen, Michael Chun-Yuan; Fiege, Jason; Franzmann, Erica; Hatchell, Jennifer; Lacaille, Kevin; Matthews, Brenda C.; Moriarty-Schieven, Gerald H.; Pon, Andy; André, Philippe; Arzoumanian, Doris; Aso, Yusuke; Byun, Do-Young; Eswaraiah, Chakali; Chen, Huei-Ru; Chen, Wen Ping; Ching, Tao-Chung; Cho, Jungyeon; Choi, Minho; Chrysostomou, Antonio; Chung, Eun Jung; Doi, Yasuo; Drabek-Maunder, Emily; Dowell, C. Darren; Eyres, Stewart P. S.; Falle, Sam; Friberg, Per; Fuller, Gary; Furuya, Ray S.; Gledhill, Tim; Graves, Sarah F.; Greaves, Jane S.; Griffin, Matt J.; Gu, Qilao; Hayashi, Saeko S.; Hoang, Thiem; Holland, Wayne; Inoue, Tsuyoshi; Inutsuka, Shu-ichiro; Iwasaki, Kazunari; Jeong, Il-Gyo; Kanamori, Yoshihiro; Kataoka, Akimasa; Kang, Ji-hyun; Kang, Miju; Kang, Sung-ju; Kawabata, Koji S.; Kemper, Francisca; Kim, Gwanjeong; Kim, Jongsoo; Kim, Kee-Tae; Kim, Kyoung Hee; Kim, Mi-Ryang; Kim, Shinyoung; Kirk, Jason M.; Kobayashi, Masato I. N.; Koch, Patrick M.; Kwon, Jungmi; Lee, Jeong-Eun; Lee, Chang Won; Lee, Sang-Sung; Li, Dalei; Li, Di; Li, Hua-Bai; Liu, Hong-Li; Liu, Junhao; Liu, Sheng-Yuan; Liu, Tie; Van Loo, Sven; Lyo, A. -Ran; Matsumura, Masafumi; Nagata, Tetsuya; Nakamura, Fumitaka; Nakanishi, Hiroyuki; Ohashi, Nagayoshi; Onaka, Takashi; Parsons, Harriet; Pattle, Kate; Peretto, Nicolas; Pyo, Tae-Soo; Qian, Lei; Rao, Ramprasad; Rawlings, Mark G.; Retter, Brendan; Richer, John; Rigby, Andrew; Robitaille, Jean-François; Saito, Hiro; Savini, Giorgio; Scaife, Anna M. M.; Seta, Masumichi; Shinnaga, Hiroko; Soam, Archana; Tamura, Motohide; Tang, Ya-Wen; Tomisaka, Kohji; Tsukamoto, Yusuke; Wang, Hongchi; Wang, Jia-Wei; Whitworth, Anthony P.; Yen, Hsi-Wei; Yoo, Hyunju; Yuan, Jinghua; Zenko, Tetsuya; Zhang, Chuan-Peng; Zhang, Guoyin; Zhou, Jianjun; Zhu, Lei; The B-fields In STar-forming Regions Observations (BISTRO Collaboration
Abstract: We present the POL-2 850 μm linear polarization map of the Barnard 1 clump in the Perseus molecular cloud complex from the B-fields In STar-forming Region Observations survey at the James Clerk Maxwell Telescope. We find a trend of decreasing polarization fraction as a function of total intensity, which we link to depolarization effects toward higher-density regions of the cloud. We then use the polarization data at 850 μm to infer the plane-of-sky orientation of the large-scale magnetic field in Barnard 1. This magnetic field runs north–south across most of the cloud, with the exception of B1-c, where it turns more east–west. From the dispersion of polarization angles, we calculate a turbulence correlation length of 5.0 ± 2.″5 (1500 au) and a turbulent-to-total magnetic energy ratio of 0.5 ± 0.3 inside the cloud. We combine this turbulent-to-total magnetic energy ratio with observations of NH3 molecular lines from the Green Bank Ammonia Survey to estimate the strength of the plane-of-sky component of the magnetic field through the Davis–Chandrasekhar–Fermi method. With a plane-of-sky amplitude of 120 ± 60 μG and a criticality criterion λ c = 3.0 ± 1.5, we find that Barnard 1 is a supercritical molecular cloud with a magnetic field nearly dominated by its turbulent component.
Type: article
Authors: Coudé, Simon; Bastien, Pierre; Houde, Martin; Sadavoy, Sarah; Friesen, Rachel; di Francesco, James; Johnstone, Doug; Mairs, Steve; Hasegawa, Tetsuo; Kwon, Woojin; Lai, Shih-Ping; Qiu, Keping; Ward-Thompson, Derek; Berry, David; Chen, Michael Chun-Yuan; Fiege, Jason; Franzmann, Erica; Hatchell, Jennifer; Lacaille, Kevin; Matthews, Brenda C.; Moriarty-Schieven, Gerald H.; Pon, Andy; André, Philippe; Arzoumanian, Doris; Aso, Yusuke; Byun, Do-Young; Eswaraiah, Chakali; Chen, Huei-Ru; Chen, Wen Ping; Ching, Tao-Chung; Cho, Jungyeon; Choi, Minho; Chrysostomou, Antonio; Chung, Eun Jung; Doi, Yasuo; Drabek-Maunder, Emily; Dowell, C. Darren; Eyres, Stewart P. S.; Falle, Sam; Friberg, Per; Fuller, Gary; Furuya, Ray S.; Gledhill, Tim; Graves, Sarah F.; Greaves, Jane S.; Griffin, Matt J.; Gu, Qilao; Hayashi, Saeko S.; Hoang, Thiem; Holland, Wayne; Inoue, Tsuyoshi; Inutsuka, Shu-ichiro; Iwasaki, Kazunari; Jeong, Il-Gyo; Kanamori, Yoshihiro; Kataoka, Akimasa; Kang, Ji-hyun; Kang, Miju; Kang, Sung-ju; Kawabata, Koji S.; Kemper, Francisca; Kim, Gwanjeong; Kim, Jongsoo; Kim, Kee-Tae; Kim, Kyoung Hee; Kim, Mi-Ryang; Kim, Shinyoung; Kirk, Jason M.; Kobayashi, Masato I. N.; Koch, Patrick M.; Kwon, Jungmi; Lee, Jeong-Eun; Lee, Chang Won; Lee, Sang-Sung; Li, Dalei; Li, Di; Li, Hua-Bai; Liu, Hong-Li; Liu, Junhao; Liu, Sheng-Yuan; Liu, Tie; Van Loo, Sven; Lyo, A. -Ran; Matsumura, Masafumi; Nagata, Tetsuya; Nakamura, Fumitaka; Nakanishi, Hiroyuki; Ohashi, Nagayoshi; Onaka, Takashi; Parsons, Harriet; Pattle, Kate; Peretto, Nicolas; Pyo, Tae-Soo; Qian, Lei; Rao, Ramprasad; Rawlings, Mark G.; Retter, Brendan; Richer, John; Rigby, Andrew; Robitaille, Jean-François; Saito, Hiro; Savini, Giorgio; Scaife, Anna M. M.; Seta, Masumichi; Shinnaga, Hiroko; Soam, Archana; Tamura, Motohide; Tang, Ya-Wen; Tomisaka, Kohji; Tsukamoto, Yusuke; Wang, Hongchi; Wang, Jia-Wei; Whitworth, Anthony P.; Yen, Hsi-Wei; Yoo, Hyunju; Yuan, Jinghua; Zenko, Tetsuya; Zhang, Chuan-Peng; Zhang, Guoyin; Zhou, Jianjun; Zhu, Lei; The B-fields In STar-forming Regions Observations (BISTRO Collaboration
Abstract: We present the POL-2 850 μm linear polarization map of the Barnard 1 clump in the Perseus molecular cloud complex from the B-fields In STar-forming Region Observations survey at the James Clerk Maxwell Telescope. We find a trend of decreasing polarization fraction as a function of total intensity, which we link to depolarization effects toward higher-density regions of the cloud. We then use the polarization data at 850 μm to infer the plane-of-sky orientation of the large-scale magnetic field in Barnard 1. This magnetic field runs north–south across most of the cloud, with the exception of B1-c, where it turns more east–west. From the dispersion of polarization angles, we calculate a turbulence correlation length of 5.0 ± 2.″5 (1500 au) and a turbulent-to-total magnetic energy ratio of 0.5 ± 0.3 inside the cloud. We combine this turbulent-to-total magnetic energy ratio with observations of NH3 molecular lines from the Green Bank Ammonia Survey to estimate the strength of the plane-of-sky component of the magnetic field through the Davis–Chandrasekhar–Fermi method. With a plane-of-sky amplitude of 120 ± 60 μG and a criticality criterion λ c = 3.0 ± 1.5, we find that Barnard 1 is a supercritical molecular cloud with a magnetic field nearly dominated by its turbulent component.
The JCMT BISTRO Survey: The Magnetic Field in the Starless Core ρ Ophiuchus CLiu, JunhaoQiu, KepingBerry, Daviddi Francesco, JamesBastien, PierreKoch, Patrick M.Furuya, Ray S.Kim, Kee-TaeCoudé, SimonLee, Chang WonSoam, ArchanaEswaraiah, ChakaliLi, DiHwang, JihyeLyo, A. -RanPattle, KateHasegawa, TetsuoKwon, WoojinLai, Shih-PingWard-Thompson, DerekChing, Tao-ChungChen, ZhiweiGu, QilaoLi, DaleiLi, Hua-BaiLiu, Hong-LiQian, LeiWang, HongchiYuan, JinghuaZhang, Chuan-PengZhang, GuoyinZhang, Ya-PengZhou, JianjunZhu, LeiAndré, PhilippeArzoumanian, DorisAso, YusukeByun, Do-YoungChen, Michael Chun-YuanChen, Huei-Ru VivienChen, Wen PingCho, JungyeonChoi, MinhoChrysostomou, AntonioChung, Eun JungDoi, YasuoDrabek-Maunder, EmilyDowell, C. DarrenEyres, Stewart P. S.Falle, SamFanciullo, LapoFiege, JasonFranzmann, EricaFriberg, PerFriesen, Rachel K.Fuller, GaryGledhill, TimGraves, Sarah F.Greaves, Jane S.Griffin, Matt J.Han, IlseungHatchell, JenniferHayashi, Saeko S.Hoang, ThiemHolland, WayneHoude, MartinInoue, TsuyoshiInutsuka, Shu-ichiroIwasaki, KazunariJeong, Il-GyoJohnstone, DougKanamori, YoshihiroKang, Ji-hyunKang, MijuKang, Sung-juKataoka, AkimasaKawabata, Koji S.Kemper, FranciscaKim, GwanjeongKim, JongsooKim, Kyoung HeeKim, Mi-RyangKim, ShinyoungKirk, Jason M.Kobayashi, Masato I. N.Kusune, TakayoshiKwon, JungmiLacaille, Kevin M.Lee, Chin-FeiLee, Jeong-EunLee, HyeseungLee, Sang-SungLiu, Sheng-YuanLiu, TieVan Loo, SvenMairs, SteveMatsumura, MasafumiMatthews, Brenda C.Moriarty-Schieven, Gerald H.Nagata, TetsuyaNakamura, FumitakaNakanishi, HiroyukiOhashi, NagayoshiOnaka, TakashiParker, JoshParsons, HarrietPascale, EnzoPeretto, NicolasPon, AndyPyo, Tae-SooRao, RamprasadRawlings, Mark G.Retter, BrendanRicher, JohnRigby, AndrewRobitaille, Jean-FrançoisSadavoy, SarahSaito, HiroSavini, GiorgioScaife, Anna M. M.Seta, MasumichiShinnaga, HirokoTamura, MotohideTang, Ya-WenTomisaka, KohjiTsukamoto, YusukeWang, Jia-WeiWhitworth, Anthony P.Yen, Hsi-WeiYoo, HyunjuZenko, TetsuyaDOI: info:10.3847/1538-4357/ab0958v. 87743
Liu, Junhao, Qiu, Keping, Berry, David, di Francesco, James, Bastien, Pierre, Koch, Patrick M., Furuya, Ray S., Kim, Kee-Tae, Coudé, Simon, Lee, Chang Won, Soam, Archana, Eswaraiah, Chakali, Li, Di, Hwang, Jihye, Lyo, A. -Ran, Pattle, Kate, Hasegawa, Tetsuo, Kwon, Woojin, Lai, Shih-Ping, Ward-Thompson, Derek, Ching, Tao-Chung, Chen, Zhiwei, Gu, Qilao, Li, Dalei, Li, Hua-Bai et al. 2019. "The JCMT BISTRO Survey: The Magnetic Field in the Starless Core ρ Ophiuchus C." The Astrophysical Journal 877:43. https://doi.org/10.3847/1538-4357/ab0958
ID: 151856
Type: article
Authors: Liu, Junhao; Qiu, Keping; Berry, David; di Francesco, James; Bastien, Pierre; Koch, Patrick M.; Furuya, Ray S.; Kim, Kee-Tae; Coudé, Simon; Lee, Chang Won; Soam, Archana; Eswaraiah, Chakali; Li, Di; Hwang, Jihye; Lyo, A. -Ran; Pattle, Kate; Hasegawa, Tetsuo; Kwon, Woojin; Lai, Shih-Ping; Ward-Thompson, Derek; Ching, Tao-Chung; Chen, Zhiwei; Gu, Qilao; Li, Dalei; Li, Hua-Bai; Liu, Hong-Li; Qian, Lei; Wang, Hongchi; Yuan, Jinghua; Zhang, Chuan-Peng; Zhang, Guoyin; Zhang, Ya-Peng; Zhou, Jianjun; Zhu, Lei; André, Philippe; Arzoumanian, Doris; Aso, Yusuke; Byun, Do-Young; Chen, Michael Chun-Yuan; Chen, Huei-Ru Vivien; Chen, Wen Ping; Cho, Jungyeon; Choi, Minho; Chrysostomou, Antonio; Chung, Eun Jung; Doi, Yasuo; Drabek-Maunder, Emily; Dowell, C. Darren; Eyres, Stewart P. S.; Falle, Sam; Fanciullo, Lapo; Fiege, Jason; Franzmann, Erica; Friberg, Per; Friesen, Rachel K.; Fuller, Gary; Gledhill, Tim; Graves, Sarah F.; Greaves, Jane S.; Griffin, Matt J.; Han, Ilseung; Hatchell, Jennifer; Hayashi, Saeko S.; Hoang, Thiem; Holland, Wayne; Houde, Martin; Inoue, Tsuyoshi; Inutsuka, Shu-ichiro; Iwasaki, Kazunari; Jeong, Il-Gyo; Johnstone, Doug; Kanamori, Yoshihiro; Kang, Ji-hyun; Kang, Miju; Kang, Sung-ju; Kataoka, Akimasa; Kawabata, Koji S.; Kemper, Francisca; Kim, Gwanjeong; Kim, Jongsoo; Kim, Kyoung Hee; Kim, Mi-Ryang; Kim, Shinyoung; Kirk, Jason M.; Kobayashi, Masato I. N.; Kusune, Takayoshi; Kwon, Jungmi; Lacaille, Kevin M.; Lee, Chin-Fei; Lee, Jeong-Eun; Lee, Hyeseung; Lee, Sang-Sung; Liu, Sheng-Yuan; Liu, Tie; Van Loo, Sven; Mairs, Steve; Matsumura, Masafumi; Matthews, Brenda C.; Moriarty-Schieven, Gerald H.; Nagata, Tetsuya; Nakamura, Fumitaka; Nakanishi, Hiroyuki; Ohashi, Nagayoshi; Onaka, Takashi; Parker, Josh; Parsons, Harriet; Pascale, Enzo; Peretto, Nicolas; Pon, Andy; Pyo, Tae-Soo; Rao, Ramprasad; Rawlings, Mark G.; Retter, Brendan; Richer, John; Rigby, Andrew; Robitaille, Jean-François; Sadavoy, Sarah; Saito, Hiro; Savini, Giorgio; Scaife, Anna M. M.; Seta, Masumichi; Shinnaga, Hiroko; Tamura, Motohide; Tang, Ya-Wen; Tomisaka, Kohji; Tsukamoto, Yusuke; Wang, Jia-Wei; Whitworth, Anthony P.; Yen, Hsi-Wei; Yoo, Hyunju; Zenko, Tetsuya
Abstract: We report 850 μm dust polarization observations of a low-mass (∼12 M ⊙) starless core in the ρ Ophiuchus cloud, Ophiuchus C, made with the POL-2 instrument on the James Clerk Maxwell Telescope (JCMT) as part of the JCMT B-fields In STar-forming Region Observations survey. We detect an ordered magnetic field projected on the plane of the sky in the starless core. The magnetic field across the ∼0.1 pc core shows a predominant northeast–southwest orientation centering between ∼40° and ∼100°, indicating that the field in the core is well aligned with the magnetic field in lower-density regions of the cloud probed by near-infrared observations and also the cloud-scale magnetic field traced by Planck observations. The polarization percentage (P) decreases with increasing total intensity (I), with a power-law index of ‑1.03 ± 0.05. We estimate the plane-of-sky field strength (B pos) using modified Davis–Chandrasekhar–Fermi methods based on structure function (SF), autocorrelation function (ACF), and unsharp masking (UM) analyses. We find that the estimates from the SF, ACF, and UM methods yield strengths of 103 ± 46 μG, 136 ± 69 μG, and 213 ± 115 μG, respectively. Our calculations suggest that the Ophiuchus C core is near magnetically critical or slightly magnetically supercritical (i.e., unstable to collapse). The total magnetic energy calculated from the SF method is comparable to the turbulent energy in Ophiuchus C, while the ACF method and the UM method only set upper limits for the total magnetic energy because of large uncertainties.
Type: article
Authors: Liu, Junhao; Qiu, Keping; Berry, David; di Francesco, James; Bastien, Pierre; Koch, Patrick M.; Furuya, Ray S.; Kim, Kee-Tae; Coudé, Simon; Lee, Chang Won; Soam, Archana; Eswaraiah, Chakali; Li, Di; Hwang, Jihye; Lyo, A. -Ran; Pattle, Kate; Hasegawa, Tetsuo; Kwon, Woojin; Lai, Shih-Ping; Ward-Thompson, Derek; Ching, Tao-Chung; Chen, Zhiwei; Gu, Qilao; Li, Dalei; Li, Hua-Bai; Liu, Hong-Li; Qian, Lei; Wang, Hongchi; Yuan, Jinghua; Zhang, Chuan-Peng; Zhang, Guoyin; Zhang, Ya-Peng; Zhou, Jianjun; Zhu, Lei; André, Philippe; Arzoumanian, Doris; Aso, Yusuke; Byun, Do-Young; Chen, Michael Chun-Yuan; Chen, Huei-Ru Vivien; Chen, Wen Ping; Cho, Jungyeon; Choi, Minho; Chrysostomou, Antonio; Chung, Eun Jung; Doi, Yasuo; Drabek-Maunder, Emily; Dowell, C. Darren; Eyres, Stewart P. S.; Falle, Sam; Fanciullo, Lapo; Fiege, Jason; Franzmann, Erica; Friberg, Per; Friesen, Rachel K.; Fuller, Gary; Gledhill, Tim; Graves, Sarah F.; Greaves, Jane S.; Griffin, Matt J.; Han, Ilseung; Hatchell, Jennifer; Hayashi, Saeko S.; Hoang, Thiem; Holland, Wayne; Houde, Martin; Inoue, Tsuyoshi; Inutsuka, Shu-ichiro; Iwasaki, Kazunari; Jeong, Il-Gyo; Johnstone, Doug; Kanamori, Yoshihiro; Kang, Ji-hyun; Kang, Miju; Kang, Sung-ju; Kataoka, Akimasa; Kawabata, Koji S.; Kemper, Francisca; Kim, Gwanjeong; Kim, Jongsoo; Kim, Kyoung Hee; Kim, Mi-Ryang; Kim, Shinyoung; Kirk, Jason M.; Kobayashi, Masato I. N.; Kusune, Takayoshi; Kwon, Jungmi; Lacaille, Kevin M.; Lee, Chin-Fei; Lee, Jeong-Eun; Lee, Hyeseung; Lee, Sang-Sung; Liu, Sheng-Yuan; Liu, Tie; Van Loo, Sven; Mairs, Steve; Matsumura, Masafumi; Matthews, Brenda C.; Moriarty-Schieven, Gerald H.; Nagata, Tetsuya; Nakamura, Fumitaka; Nakanishi, Hiroyuki; Ohashi, Nagayoshi; Onaka, Takashi; Parker, Josh; Parsons, Harriet; Pascale, Enzo; Peretto, Nicolas; Pon, Andy; Pyo, Tae-Soo; Rao, Ramprasad; Rawlings, Mark G.; Retter, Brendan; Richer, John; Rigby, Andrew; Robitaille, Jean-François; Sadavoy, Sarah; Saito, Hiro; Savini, Giorgio; Scaife, Anna M. M.; Seta, Masumichi; Shinnaga, Hiroko; Tamura, Motohide; Tang, Ya-Wen; Tomisaka, Kohji; Tsukamoto, Yusuke; Wang, Jia-Wei; Whitworth, Anthony P.; Yen, Hsi-Wei; Yoo, Hyunju; Zenko, Tetsuya
Abstract: We report 850 μm dust polarization observations of a low-mass (∼12 M ⊙) starless core in the ρ Ophiuchus cloud, Ophiuchus C, made with the POL-2 instrument on the James Clerk Maxwell Telescope (JCMT) as part of the JCMT B-fields In STar-forming Region Observations survey. We detect an ordered magnetic field projected on the plane of the sky in the starless core. The magnetic field across the ∼0.1 pc core shows a predominant northeast–southwest orientation centering between ∼40° and ∼100°, indicating that the field in the core is well aligned with the magnetic field in lower-density regions of the cloud probed by near-infrared observations and also the cloud-scale magnetic field traced by Planck observations. The polarization percentage (P) decreases with increasing total intensity (I), with a power-law index of ‑1.03 ± 0.05. We estimate the plane-of-sky field strength (B pos) using modified Davis–Chandrasekhar–Fermi methods based on structure function (SF), autocorrelation function (ACF), and unsharp masking (UM) analyses. We find that the estimates from the SF, ACF, and UM methods yield strengths of 103 ± 46 μG, 136 ± 69 μG, and 213 ± 115 μG, respectively. Our calculations suggest that the Ophiuchus C core is near magnetically critical or slightly magnetically supercritical (i.e., unstable to collapse). The total magnetic energy calculated from the SF method is comparable to the turbulent energy in Ophiuchus C, while the ACF method and the UM method only set upper limits for the total magnetic energy because of large uncertainties.
Dust in supernovae: - Do supernovae produce the first dust in the Universe? Are supernovae the key dust producers of galaxies?Matsuura, MikakoInserra, C.Meixner, M.Armus, LeeBevan, A.de Looze, I.Gomez, H. L.Sadavoy, SarahAndrew, J. E. E.Barlow, M. J.Clayton, G. C.Rho, J. H.
Matsuura, Mikako, Inserra, C., Meixner, M., Armus, Lee, Bevan, A., de Looze, I., Gomez, H. L., Sadavoy, Sarah, Andrew, J. E. E., Barlow, M. J., Clayton, G. C., and Rho, J. H. 2019. [Report] Dust in supernovae: - Do supernovae produce the first dust in the Universe? Are supernovae the key dust producers of galaxies?. http://adsabs.harvard.edu/abs/2019astro2020T.573M.
ID: 151854
Type: report
Authors: Matsuura, Mikako; Inserra, C.; Meixner, M.; Armus, Lee; Bevan, A.; de Looze, I.; Gomez, H. L.; Sadavoy, Sarah; Andrew, J. E. E.; Barlow, M. J.; Clayton, G. C.; Rho, J. H.
Abstract: This White Paper debates whether supernovae produce the first dust in the Universe, and how this debate will be tested with forthcoming telescopes.
Type: report
Authors: Matsuura, Mikako; Inserra, C.; Meixner, M.; Armus, Lee; Bevan, A.; de Looze, I.; Gomez, H. L.; Sadavoy, Sarah; Andrew, J. E. E.; Barlow, M. J.; Clayton, G. C.; Rho, J. H.
Abstract: This White Paper debates whether supernovae produce the first dust in the Universe, and how this debate will be tested with forthcoming telescopes.
JCMT BISTRO Survey Observations of the Ophiuchus Molecular Cloud: Dust Grain Alignment Properties Inferred Using a Ricean Noise ModelPattle, KateLai, Shih-PingHasegawa, TetsuoWang, Jia-WeiFuruya, Ray S.Ward-Thompson, DerekBastien, PierreCoudé, SimonEswaraiah, ChakaliFanciullo, Lapodi Francesco, JamesHoang, ThiemKim, GwanjeongKwon, WoojinLee, Chang WonLiu, Sheng-YuanLiu, TieMatsumura, MasafumiOnaka, TakashiSadavoy, SarahSoam, ArchanaDOI: info:10.3847/1538-4357/ab286fv. 88027
Pattle, Kate, Lai, Shih-Ping, Hasegawa, Tetsuo, Wang, Jia-Wei, Furuya, Ray S., Ward-Thompson, Derek, Bastien, Pierre, Coudé, Simon, Eswaraiah, Chakali, Fanciullo, Lapo, di Francesco, James, Hoang, Thiem, Kim, Gwanjeong, Kwon, Woojin, Lee, Chang Won, Liu, Sheng-Yuan, Liu, Tie, Matsumura, Masafumi, Onaka, Takashi, Sadavoy, Sarah, and Soam, Archana. 2019. "JCMT BISTRO Survey Observations of the Ophiuchus Molecular Cloud: Dust Grain Alignment Properties Inferred Using a Ricean Noise Model." The Astrophysical Journal 880:27. https://doi.org/10.3847/1538-4357/ab286f
ID: 154183
Type: article
Authors: Pattle, Kate; Lai, Shih-Ping; Hasegawa, Tetsuo; Wang, Jia-Wei; Furuya, Ray S.; Ward-Thompson, Derek; Bastien, Pierre; Coudé, Simon; Eswaraiah, Chakali; Fanciullo, Lapo; di Francesco, James; Hoang, Thiem; Kim, Gwanjeong; Kwon, Woojin; Lee, Chang Won; Liu, Sheng-Yuan; Liu, Tie; Matsumura, Masafumi; Onaka, Takashi; Sadavoy, Sarah; Soam, Archana
Abstract: The dependence of the polarization fraction p on total intensity I in polarized submillimeter emission measurements is typically parameterized as p ∝ I -α (α ≤ 1) and used to infer dust grain alignment efficiency in star-forming regions, with an index α = 1 indicating near- total lack of alignment of grains with the magnetic field. In this work, we demonstrate that the non-Gaussian noise characteristics of the polarization fraction may produce apparent measurements of α ̃ 1 even in data with significant signal-to-noise in Stokes Q, U, and I emission, and so with robust measurements of polarization angle. We present a simple model demonstrating this behavior and propose a criterion by which well-characterized measurements of the polarization fraction may be identified. We demonstrate that where our model is applicable, α can be recovered by fitting the p-I relationship with the mean of the Rice distribution without statistical debiasing of the polarization fraction. We apply our model to JCMT BISTRO Survey POL-2 850 μm observations of three clumps in the Ophiuchus molecular cloud, finding that in the externally illuminated Oph A region, α ≈ 0.34, while in the more isolated Oph B and C, despite their differing star formation histories, α ̃ 0.6-0.7. Our results thus suggest that dust grain alignment in dense gas is more strongly influenced by the incident interstellar radiation field than by star formation history. We further find that grains may remain aligned with the magnetic field at significantly higher gas densities than has previously been believed, thus allowing investigation of magnetic field properties within star-forming clumps and cores.
Type: article
Authors: Pattle, Kate; Lai, Shih-Ping; Hasegawa, Tetsuo; Wang, Jia-Wei; Furuya, Ray S.; Ward-Thompson, Derek; Bastien, Pierre; Coudé, Simon; Eswaraiah, Chakali; Fanciullo, Lapo; di Francesco, James; Hoang, Thiem; Kim, Gwanjeong; Kwon, Woojin; Lee, Chang Won; Liu, Sheng-Yuan; Liu, Tie; Matsumura, Masafumi; Onaka, Takashi; Sadavoy, Sarah; Soam, Archana
Abstract: The dependence of the polarization fraction p on total intensity I in polarized submillimeter emission measurements is typically parameterized as p ∝ I -α (α ≤ 1) and used to infer dust grain alignment efficiency in star-forming regions, with an index α = 1 indicating near- total lack of alignment of grains with the magnetic field. In this work, we demonstrate that the non-Gaussian noise characteristics of the polarization fraction may produce apparent measurements of α ̃ 1 even in data with significant signal-to-noise in Stokes Q, U, and I emission, and so with robust measurements of polarization angle. We present a simple model demonstrating this behavior and propose a criterion by which well-characterized measurements of the polarization fraction may be identified. We demonstrate that where our model is applicable, α can be recovered by fitting the p-I relationship with the mean of the Rice distribution without statistical debiasing of the polarization fraction. We apply our model to JCMT BISTRO Survey POL-2 850 μm observations of three clumps in the Ophiuchus molecular cloud, finding that in the externally illuminated Oph A region, α ≈ 0.34, while in the more isolated Oph B and C, despite their differing star formation histories, α ̃ 0.6-0.7. Our results thus suggest that dust grain alignment in dense gas is more strongly influenced by the incident interstellar radiation field than by star formation history. We further find that grains may remain aligned with the magnetic field at significantly higher gas densities than has previously been believed, thus allowing investigation of magnetic field properties within star-forming clumps and cores.
Dust Polarization toward Embedded Protostars in Ophiuchus with ALMA. III. Survey OverviewSadavoy, Sarah I.Stephens, Ian W.Myers, Philip C.Looney, LeslieTobin, JohnKwon, WoojinCommerçon, BenoîtSegura-Cox, DominiqueHenning, ThomasHennebelle, PatrickDOI: info:10.3847/1538-4365/ab4257v. 2452
Sadavoy, Sarah I., Stephens, Ian W., Myers, Philip C., Looney, Leslie, Tobin, John, Kwon, Woojin, Commerçon, Benoît, Segura-Cox, Dominique, Henning, Thomas, and Hennebelle, Patrick. 2019. "Dust Polarization toward Embedded Protostars in Ophiuchus with ALMA. III. Survey Overview." The Astrophysical Journal Supplement Series 245:2. https://doi.org/10.3847/1538-4365/ab4257
ID: 154596
Type: article
Authors: Sadavoy, Sarah I.; Stephens, Ian W.; Myers, Philip C.; Looney, Leslie; Tobin, John; Kwon, Woojin; Commerçon, Benoît; Segura-Cox, Dominique; Henning, Thomas; Hennebelle, Patrick
Abstract: We present 0.″25 resolution (35 au) ALMA 1.3 mm dust polarization observations for 37 young stellar objects (YSOs) in the Ophiuchus molecular cloud. These data encompass all the embedded protostars in the cloud and several flat-spectrum and Class II objects to produce the largest, homogeneous study of dust polarization on disk scales to date. The goal of this study is to study dust polarization morphologies down to disk scales. We find that 14/37 (38%) of the observed YSOs are detected in polarization at our sensitivity. Nine of these sources have uniform polarization angles, and four sources have azimuthal polarization structure. We find that the sources with uniform polarization tend to have steeper inclinations (>60°) than those with azimuthal polarization (60° are the best candidates for future polarization studies of dust self-scattering, as these systems will generally show uniform polarization vectors that do not require very high resolution to resolve. We release the continuum and polarization images for all the sources with this publication. Data from the entire survey can be obtained from Dataverse.
Type: article
Authors: Sadavoy, Sarah I.; Stephens, Ian W.; Myers, Philip C.; Looney, Leslie; Tobin, John; Kwon, Woojin; Commerçon, Benoît; Segura-Cox, Dominique; Henning, Thomas; Hennebelle, Patrick
Abstract: We present 0.″25 resolution (35 au) ALMA 1.3 mm dust polarization observations for 37 young stellar objects (YSOs) in the Ophiuchus molecular cloud. These data encompass all the embedded protostars in the cloud and several flat-spectrum and Class II objects to produce the largest, homogeneous study of dust polarization on disk scales to date. The goal of this study is to study dust polarization morphologies down to disk scales. We find that 14/37 (38%) of the observed YSOs are detected in polarization at our sensitivity. Nine of these sources have uniform polarization angles, and four sources have azimuthal polarization structure. We find that the sources with uniform polarization tend to have steeper inclinations (>60°) than those with azimuthal polarization (60° are the best candidates for future polarization studies of dust self-scattering, as these systems will generally show uniform polarization vectors that do not require very high resolution to resolve. We release the continuum and polarization images for all the sources with this publication. Data from the entire survey can be obtained from Dataverse.
Mass Assembly of Stellar Systems and Their Evolution with the SMA (MASSES)-Full Data ReleaseStephens, Ian W.Bourke, Tyler L.Dunham, Michael M.Myers, Philip C.Pokhrel, RiwajTobin, John J.Arce, Héctor G.Sadavoy, Sarah I.Vorobyov, Eduard I.Pineda, Jaime E.Offner, Stella S. R.Lee, Katherine I.Kristensen, Lars E.Jørgensen, Jes K.Gurwell, Mark A.Goodman, Alyssa A.DOI: info:10.3847/1538-4365/ab5181v. 24521
Stephens, Ian W., Bourke, Tyler L., Dunham, Michael M., Myers, Philip C., Pokhrel, Riwaj, Tobin, John J., Arce, Héctor G., Sadavoy, Sarah I., Vorobyov, Eduard I., Pineda, Jaime E., Offner, Stella S. R., Lee, Katherine I., Kristensen, Lars E., Jørgensen, Jes K., Gurwell, Mark A., and Goodman, Alyssa A. 2019. "Mass Assembly of Stellar Systems and Their Evolution with the SMA (MASSES)-Full Data Release." The Astrophysical Journal Supplement Series 245:21. https://doi.org/10.3847/1538-4365/ab5181
ID: 154516
Type: article
Authors: Stephens, Ian W.; Bourke, Tyler L.; Dunham, Michael M.; Myers, Philip C.; Pokhrel, Riwaj; Tobin, John J.; Arce, Héctor G.; Sadavoy, Sarah I.; Vorobyov, Eduard I.; Pineda, Jaime E.; Offner, Stella S. R.; Lee, Katherine I.; Kristensen, Lars E.; Jørgensen, Jes K.; Gurwell, Mark A.; Goodman, Alyssa A.
Abstract: We present and release the full data set for the Mass Assembly of Stellar Systems and their Evolution with the SMA (MASSES) survey. This survey used the Submillimeter Array (SMA) to image the 74 known protostars within the Perseus molecular cloud. The SMA was used in two array configurations to capture outflows for scales >30″ (>9000 au) and to probe scales down to ∼1″ (∼300 au). The protostars were observed with the 1.3 mm and 850 μm receivers simultaneously to detect continuum at both wavelengths and molecular line emission from CO(2─1), 13CO(2─1), C18O(2─1), N2D+(3─2), CO(3─2), HCO+(4─3), and H13CO+(4─3). Some of the observations also used the SMA's recently upgraded correlator, SWARM, whose broader bandwidth allowed for several more spectral lines to be observed (e.g., SO, H2CO, DCO+, DCN, CS, CN). Of the main continuum and spectral tracers observed, 84% of the images and cubes had emission detected. The median C18O(2─1) line width is ∼1.0 km s−1, which is slightly higher than those measured with single-dish telescopes at scales of 3000─20,000 au. Of the 74 targets, six are suggested to be first hydrostatic core candidates, and we suggest that L1451-mm is the best candidate. We question a previous continuum detection toward L1448 IRS2E. In the SVS 13 system, SVS 13A certainly appears to be the most evolved source, while SVS 13C appears to be hotter and more evolved than SVS 13B. The MASSES survey is the largest publicly available interferometric continuum and spectral line protostellar survey to date, and is largely unbiased as it only targets protostars in Perseus. All visibility (uv) data and imaged data are publicly available at https://dataverse.harvard.edu/dataverse/full_MASSES/.
Type: article
Authors: Stephens, Ian W.; Bourke, Tyler L.; Dunham, Michael M.; Myers, Philip C.; Pokhrel, Riwaj; Tobin, John J.; Arce, Héctor G.; Sadavoy, Sarah I.; Vorobyov, Eduard I.; Pineda, Jaime E.; Offner, Stella S. R.; Lee, Katherine I.; Kristensen, Lars E.; Jørgensen, Jes K.; Gurwell, Mark A.; Goodman, Alyssa A.
Abstract: We present and release the full data set for the Mass Assembly of Stellar Systems and their Evolution with the SMA (MASSES) survey. This survey used the Submillimeter Array (SMA) to image the 74 known protostars within the Perseus molecular cloud. The SMA was used in two array configurations to capture outflows for scales >30″ (>9000 au) and to probe scales down to ∼1″ (∼300 au). The protostars were observed with the 1.3 mm and 850 μm receivers simultaneously to detect continuum at both wavelengths and molecular line emission from CO(2─1), 13CO(2─1), C18O(2─1), N2D+(3─2), CO(3─2), HCO+(4─3), and H13CO+(4─3). Some of the observations also used the SMA's recently upgraded correlator, SWARM, whose broader bandwidth allowed for several more spectral lines to be observed (e.g., SO, H2CO, DCO+, DCN, CS, CN). Of the main continuum and spectral tracers observed, 84% of the images and cubes had emission detected. The median C18O(2─1) line width is ∼1.0 km s−1, which is slightly higher than those measured with single-dish telescopes at scales of 3000─20,000 au. Of the 74 targets, six are suggested to be first hydrostatic core candidates, and we suggest that L1451-mm is the best candidate. We question a previous continuum detection toward L1448 IRS2E. In the SVS 13 system, SVS 13A certainly appears to be the most evolved source, while SVS 13C appears to be hotter and more evolved than SVS 13B. The MASSES survey is the largest publicly available interferometric continuum and spectral line protostellar survey to date, and is largely unbiased as it only targets protostars in Perseus. All visibility (uv) data and imaged data are publicly available at https://dataverse.harvard.edu/dataverse/full_MASSES/.
The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. I. Identifying and Characterizing the Protostellar Content of the OMC-2 FIR4 and OMC-2 FIR3 RegionsTobin, John J.Megeath, S. Thomasvan't Hoff, MerelDíaz-Rodríguez, Ana KarlaReynolds, NickalasOsorio, MayraAnglada, GuillemFurlan, EliseKarnath, NicoleOffner, Stella S. R.Sheehan, Patrick D.Sadavoy, Sarah I.Stutz, Amelia M.Fischer, William J.Kama, MihkelPersson, Magnusdi Francesco, JamesLooney, Leslie W.Watson, Dan M.Li, Zhi-YunStephens, IanChandler, Claire J.Cox, ErinDunham, Michael M.Kratter, KaitlinKounkel, MarinaMazur, BrianMurillo, Nadia M.Patel, LisaPerez, LauraSegura-Cox, DominiqueSharma, RajeebTychoniec, ŁukaszWyrowski, FriedrichDOI: info:10.3847/1538-4357/ab498fv. 8866
Tobin, John J., Megeath, S. Thomas, van't Hoff, Merel, Díaz-Rodríguez, Ana Karla, Reynolds, Nickalas, Osorio, Mayra, Anglada, Guillem, Furlan, Elise, Karnath, Nicole, Offner, Stella S. R., Sheehan, Patrick D., Sadavoy, Sarah I., Stutz, Amelia M., Fischer, William J., Kama, Mihkel, Persson, Magnus, di Francesco, James, Looney, Leslie W., Watson, Dan M., Li, Zhi-Yun, Stephens, Ian, Chandler, Claire J., Cox, Erin, Dunham, Michael M., Kratter, Kaitlin et al. 2019. "The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. I. Identifying and Characterizing the Protostellar Content of the OMC-2 FIR4 and OMC-2 FIR3 Regions." The Astrophysical Journal 886:6. https://doi.org/10.3847/1538-4357/ab498f
ID: 154585
Type: article
Authors: Tobin, John J.; Megeath, S. Thomas; van't Hoff, Merel; Díaz-Rodríguez, Ana Karla; Reynolds, Nickalas; Osorio, Mayra; Anglada, Guillem; Furlan, Elise; Karnath, Nicole; Offner, Stella S. R.; Sheehan, Patrick D.; Sadavoy, Sarah I.; Stutz, Amelia M.; Fischer, William J.; Kama, Mihkel; Persson, Magnus; di Francesco, James; Looney, Leslie W.; Watson, Dan M.; Li, Zhi-Yun; Stephens, Ian; Chandler, Claire J.; Cox, Erin; Dunham, Michael M.; Kratter, Kaitlin; Kounkel, Marina; Mazur, Brian; Murillo, Nadia M.; Patel, Lisa; Perez, Laura; Segura-Cox, Dominique; Sharma, Rajeeb; Tychoniec, Łukasz; Wyrowski, Friedrich
Abstract: We present Atacama Large Millimeter/submillimeter Array (0.87 mm) and Very Large Array (9 mm) observations toward OMC-2 FIR4 and OMC-2 FIR3 within the Orion integral-shaped filament, thought to be two of the nearest regions of intermediate-mass star formation. We characterize the continuum sources within these regions on ∼40 au (0.″1) scales and associated molecular line emission at a factor of ∼30 better resolution than previous observations at similar wavelengths. We identify six compact continuum sources within OMC-2 FIR4, four in OMC-2 FIR3, and one additional source just outside OMC-2 FIR4. This continuum emission is tracing the inner envelope and/or disk emission on less than 100 au scales. HOPS-108 is the only protostar in OMC-2 FIR4 that exhibits emission from high-excitation transitions of complex organic molecules (e.g., methanol and other lines) coincident with the continuum emission. HOPS-370 in OMC-2 FIR3, with L ∼ 360 L ☉, also exhibits emission from high-excitation methanol and other lines. The methanol emission toward these two protostars is indicative of temperatures high enough to thermally evaporate it from icy dust grains; overall, these protostars have characteristics similar to hot corinos. We do not identify a clear outflow from HOPS-108 in 12CO, but we find evidence of interaction between the outflow/jet from HOPS-370 and the OMC-2 FIR4 region. A multitude of observational constraints indicate that HOPS-108 is likely a low- to intermediate-mass protostar in its main mass accretion phase and is the most luminous protostar in OMC-2 FIR4. The high-resolution data presented here are essential for disentangling the embedded protostars from their surrounding dusty environments and characterizing them.
Type: article
Authors: Tobin, John J.; Megeath, S. Thomas; van't Hoff, Merel; Díaz-Rodríguez, Ana Karla; Reynolds, Nickalas; Osorio, Mayra; Anglada, Guillem; Furlan, Elise; Karnath, Nicole; Offner, Stella S. R.; Sheehan, Patrick D.; Sadavoy, Sarah I.; Stutz, Amelia M.; Fischer, William J.; Kama, Mihkel; Persson, Magnus; di Francesco, James; Looney, Leslie W.; Watson, Dan M.; Li, Zhi-Yun; Stephens, Ian; Chandler, Claire J.; Cox, Erin; Dunham, Michael M.; Kratter, Kaitlin; Kounkel, Marina; Mazur, Brian; Murillo, Nadia M.; Patel, Lisa; Perez, Laura; Segura-Cox, Dominique; Sharma, Rajeeb; Tychoniec, Łukasz; Wyrowski, Friedrich
Abstract: We present Atacama Large Millimeter/submillimeter Array (0.87 mm) and Very Large Array (9 mm) observations toward OMC-2 FIR4 and OMC-2 FIR3 within the Orion integral-shaped filament, thought to be two of the nearest regions of intermediate-mass star formation. We characterize the continuum sources within these regions on ∼40 au (0.″1) scales and associated molecular line emission at a factor of ∼30 better resolution than previous observations at similar wavelengths. We identify six compact continuum sources within OMC-2 FIR4, four in OMC-2 FIR3, and one additional source just outside OMC-2 FIR4. This continuum emission is tracing the inner envelope and/or disk emission on less than 100 au scales. HOPS-108 is the only protostar in OMC-2 FIR4 that exhibits emission from high-excitation transitions of complex organic molecules (e.g., methanol and other lines) coincident with the continuum emission. HOPS-370 in OMC-2 FIR3, with L ∼ 360 L ☉, also exhibits emission from high-excitation methanol and other lines. The methanol emission toward these two protostars is indicative of temperatures high enough to thermally evaporate it from icy dust grains; overall, these protostars have characteristics similar to hot corinos. We do not identify a clear outflow from HOPS-108 in 12CO, but we find evidence of interaction between the outflow/jet from HOPS-370 and the OMC-2 FIR4 region. A multitude of observational constraints indicate that HOPS-108 is likely a low- to intermediate-mass protostar in its main mass accretion phase and is the most luminous protostar in OMC-2 FIR4. The high-resolution data presented here are essential for disentangling the embedded protostars from their surrounding dusty environments and characterizing them.
JCMT BISTRO Survey: Magnetic Fields within the Hub-filament Structure in IC 5146Wang, Jia-WeiLai, Shih-PingEswaraiah, ChakaliPattle, Katedi Francesco, JamesJohnstone, DougKoch, Patrick M.Liu, TieTamura, MotohideFuruya, Ray S.Onaka, TakashiWard-Thompson, DerekSoam, ArchanaKim, Kee-TaeLee, Chang WonLee, Chin-FeiMairs, SteveArzoumanian, DorisKim, GwanjeongHoang, ThiemHwang, JihyeLiu, Sheng-YuanBerry, DavidBastien, PierreHasegawa, TetsuoKwon, WoojinQiu, KepingAndré, PhilippeAso, YusukeByun, Do-YoungChen, Huei-RuChen, Michael C.Chen, Wen PingChing, Tao-ChungCho, JungyeonChoi, MinhoChrysostomou, AntonioChung, Eun JungCoudé, SimonDoi, YasuoDowell, C. DarrenDrabek-Maunder, EmilyDuan, Hao-YuanEyres, Stewart P. S.Falle, SamFanciullo, LapoFiege, JasonFranzmann, EricaFriberg, PerFriesen, Rachel K.Fuller, GaryGledhill, TimGraves, Sarah F.Greaves, Jane S.Griffin, Matt J.Gu, QilaoHan, IlseungHatchell, JenniferHayashi, Saeko S.Holland, WayneHoude, MartinInoue, TsuyoshiInutsuka, Shu-ichiroIwasaki, KazunariJeong, Il-GyoKanamori, YoshihiroKang, Ji-hyunKang, MijuKang, Sung-juKataoka, AkimasaKawabata, Koji S.Kemper, FranciscaKim, JongsooKim, Kyoung HeeKim, Mi-RyangKim, ShinyoungKirk, Jason M.Kobayashi, Masato I. N.Konyves, VeraKwon, JungmiLacaille, Kevin M.Lee, HyeseungLee, Jeong-EunLee, Sang-SungLee, Yong-HeeLi, DaleiLi, DiLi, Hua-BaiLiu, Hong-LiLiu, JunhaoLyo, A. -RanMatsumura, MasafumiMatthews, Brenda C.Moriarty-Schieven, Gerald H.Nagata, TetsuyaNakamura, FumitakaNakanishi, HiroyukiOhashi, NagayoshiPark, GeumsookParsons, HarrietPascale, EnzoPeretto, NicolasPon, AndyPyo, Tae-SooQian, LeiRao, RamprasadRawlings, Mark G.Retter, BrendanRicher, JohnRigby, AndrewRobitaille, Jean-FrançoisSadavoy, SarahSaito, HiroSavini, GiorgioScaife, Anna M. M.Seta, MasumichiShinnaga, HirokoTang, Ya-WenTomisaka, KohjiTsukamoto, YusukeVan Loo, SvenWang, HongchiWhitworth, Anthony P.Yen, Hsi-WeiYoo, HyunjuYuan, JinghuaYun, Hyeong-SikZenko, TetsuyaZhang, Chuan-PengZhang, GuoyinZhang, Ya-PengZhou, JianjunZhu, LeiDOI: info:10.3847/1538-4357/ab13a2v. 87642
Wang, Jia-Wei, Lai, Shih-Ping, Eswaraiah, Chakali, Pattle, Kate, di Francesco, James, Johnstone, Doug, Koch, Patrick M., Liu, Tie, Tamura, Motohide, Furuya, Ray S., Onaka, Takashi, Ward-Thompson, Derek, Soam, Archana, Kim, Kee-Tae, Lee, Chang Won, Lee, Chin-Fei, Mairs, Steve, Arzoumanian, Doris, Kim, Gwanjeong, Hoang, Thiem, Hwang, Jihye, Liu, Sheng-Yuan, Berry, David, Bastien, Pierre, Hasegawa, Tetsuo et al. 2019. "JCMT BISTRO Survey: Magnetic Fields within the Hub-filament Structure in IC 5146." The Astrophysical Journal 876:42. https://doi.org/10.3847/1538-4357/ab13a2
ID: 151857
Type: article
Authors: Wang, Jia-Wei; Lai, Shih-Ping; Eswaraiah, Chakali; Pattle, Kate; di Francesco, James; Johnstone, Doug; Koch, Patrick M.; Liu, Tie; Tamura, Motohide; Furuya, Ray S.; Onaka, Takashi; Ward-Thompson, Derek; Soam, Archana; Kim, Kee-Tae; Lee, Chang Won; Lee, Chin-Fei; Mairs, Steve; Arzoumanian, Doris; Kim, Gwanjeong; Hoang, Thiem; Hwang, Jihye; Liu, Sheng-Yuan; Berry, David; Bastien, Pierre; Hasegawa, Tetsuo; Kwon, Woojin; Qiu, Keping; André, Philippe; Aso, Yusuke; Byun, Do-Young; Chen, Huei-Ru; Chen, Michael C.; Chen, Wen Ping; Ching, Tao-Chung; Cho, Jungyeon; Choi, Minho; Chrysostomou, Antonio; Chung, Eun Jung; Coudé, Simon; Doi, Yasuo; Dowell, C. Darren; Drabek-Maunder, Emily; Duan, Hao-Yuan; Eyres, Stewart P. S.; Falle, Sam; Fanciullo, Lapo; Fiege, Jason; Franzmann, Erica; Friberg, Per; Friesen, Rachel K.; Fuller, Gary; Gledhill, Tim; Graves, Sarah F.; Greaves, Jane S.; Griffin, Matt J.; Gu, Qilao; Han, Ilseung; Hatchell, Jennifer; Hayashi, Saeko S.; Holland, Wayne; Houde, Martin; Inoue, Tsuyoshi; Inutsuka, Shu-ichiro; Iwasaki, Kazunari; Jeong, Il-Gyo; Kanamori, Yoshihiro; Kang, Ji-hyun; Kang, Miju; Kang, Sung-ju; Kataoka, Akimasa; Kawabata, Koji S.; Kemper, Francisca; Kim, Jongsoo; Kim, Kyoung Hee; Kim, Mi-Ryang; Kim, Shinyoung; Kirk, Jason M.; Kobayashi, Masato I. N.; Konyves, Vera; Kwon, Jungmi; Lacaille, Kevin M.; Lee, Hyeseung; Lee, Jeong-Eun; Lee, Sang-Sung; Lee, Yong-Hee; Li, Dalei; Li, Di; Li, Hua-Bai; Liu, Hong-Li; Liu, Junhao; Lyo, A. -Ran; Matsumura, Masafumi; Matthews, Brenda C.; Moriarty-Schieven, Gerald H.; Nagata, Tetsuya; Nakamura, Fumitaka; Nakanishi, Hiroyuki; Ohashi, Nagayoshi; Park, Geumsook; Parsons, Harriet; Pascale, Enzo; Peretto, Nicolas; Pon, Andy; Pyo, Tae-Soo; Qian, Lei; Rao, Ramprasad; Rawlings, Mark G.; Retter, Brendan; Richer, John; Rigby, Andrew; Robitaille, Jean-François; Sadavoy, Sarah; Saito, Hiro; Savini, Giorgio; Scaife, Anna M. M.; Seta, Masumichi; Shinnaga, Hiroko; Tang, Ya-Wen; Tomisaka, Kohji; Tsukamoto, Yusuke; Van Loo, Sven; Wang, Hongchi; Whitworth, Anthony P.; Yen, Hsi-Wei; Yoo, Hyunju; Yuan, Jinghua; Yun, Hyeong-Sik; Zenko, Tetsuya; Zhang, Chuan-Peng; Zhang, Guoyin; Zhang, Ya-Peng; Zhou, Jianjun; Zhu, Lei
Abstract: We present the 850 μm polarization observations toward the IC 5146 filamentary cloud taken using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) and its associated polarimeter (POL-2), mounted on the James Clerk Maxwell Telescope, as part of the B-fields In STar forming Regions Observations. This work is aimed at revealing the magnetic field morphology within a core-scale (≲1.0 pc) hub-filament structure (HFS) located at the end of a parsec-scale filament. To investigate whether the observed polarization traces the magnetic field in the HFS, we analyze the dependence between the observed polarization fraction and total intensity using a Bayesian approach with the polarization fraction described by the Rice likelihood function, which can correctly describe the probability density function of the observed polarization fraction for low signal-to-noise ratio data. We find a power-law dependence between the polarization fraction and total intensity with an index of 0.56 in A V ∼ 20–300 mag regions, suggesting that the dust grains in these dense regions can still be aligned with magnetic fields in the IC 5146 regions. Our polarization maps reveal a curved magnetic field, possibly dragged by the contraction along the parsec-scale filament. We further obtain a magnetic field strength of 0.5 ± 0.2 mG toward the central hub using the Davis–Chandrasekhar–Fermi method, corresponding to a mass-to-flux criticality of ∼1.3 ± 0.4 and an Alfvénic Mach number of <0.6. These results suggest that gravity and magnetic field are currently of comparable importance in the HFS and that turbulence is less important.
Type: article
Authors: Wang, Jia-Wei; Lai, Shih-Ping; Eswaraiah, Chakali; Pattle, Kate; di Francesco, James; Johnstone, Doug; Koch, Patrick M.; Liu, Tie; Tamura, Motohide; Furuya, Ray S.; Onaka, Takashi; Ward-Thompson, Derek; Soam, Archana; Kim, Kee-Tae; Lee, Chang Won; Lee, Chin-Fei; Mairs, Steve; Arzoumanian, Doris; Kim, Gwanjeong; Hoang, Thiem; Hwang, Jihye; Liu, Sheng-Yuan; Berry, David; Bastien, Pierre; Hasegawa, Tetsuo; Kwon, Woojin; Qiu, Keping; André, Philippe; Aso, Yusuke; Byun, Do-Young; Chen, Huei-Ru; Chen, Michael C.; Chen, Wen Ping; Ching, Tao-Chung; Cho, Jungyeon; Choi, Minho; Chrysostomou, Antonio; Chung, Eun Jung; Coudé, Simon; Doi, Yasuo; Dowell, C. Darren; Drabek-Maunder, Emily; Duan, Hao-Yuan; Eyres, Stewart P. S.; Falle, Sam; Fanciullo, Lapo; Fiege, Jason; Franzmann, Erica; Friberg, Per; Friesen, Rachel K.; Fuller, Gary; Gledhill, Tim; Graves, Sarah F.; Greaves, Jane S.; Griffin, Matt J.; Gu, Qilao; Han, Ilseung; Hatchell, Jennifer; Hayashi, Saeko S.; Holland, Wayne; Houde, Martin; Inoue, Tsuyoshi; Inutsuka, Shu-ichiro; Iwasaki, Kazunari; Jeong, Il-Gyo; Kanamori, Yoshihiro; Kang, Ji-hyun; Kang, Miju; Kang, Sung-ju; Kataoka, Akimasa; Kawabata, Koji S.; Kemper, Francisca; Kim, Jongsoo; Kim, Kyoung Hee; Kim, Mi-Ryang; Kim, Shinyoung; Kirk, Jason M.; Kobayashi, Masato I. N.; Konyves, Vera; Kwon, Jungmi; Lacaille, Kevin M.; Lee, Hyeseung; Lee, Jeong-Eun; Lee, Sang-Sung; Lee, Yong-Hee; Li, Dalei; Li, Di; Li, Hua-Bai; Liu, Hong-Li; Liu, Junhao; Lyo, A. -Ran; Matsumura, Masafumi; Matthews, Brenda C.; Moriarty-Schieven, Gerald H.; Nagata, Tetsuya; Nakamura, Fumitaka; Nakanishi, Hiroyuki; Ohashi, Nagayoshi; Park, Geumsook; Parsons, Harriet; Pascale, Enzo; Peretto, Nicolas; Pon, Andy; Pyo, Tae-Soo; Qian, Lei; Rao, Ramprasad; Rawlings, Mark G.; Retter, Brendan; Richer, John; Rigby, Andrew; Robitaille, Jean-François; Sadavoy, Sarah; Saito, Hiro; Savini, Giorgio; Scaife, Anna M. M.; Seta, Masumichi; Shinnaga, Hiroko; Tang, Ya-Wen; Tomisaka, Kohji; Tsukamoto, Yusuke; Van Loo, Sven; Wang, Hongchi; Whitworth, Anthony P.; Yen, Hsi-Wei; Yoo, Hyunju; Yuan, Jinghua; Yun, Hyeong-Sik; Zenko, Tetsuya; Zhang, Chuan-Peng; Zhang, Guoyin; Zhang, Ya-Peng; Zhou, Jianjun; Zhu, Lei
Abstract: We present the 850 μm polarization observations toward the IC 5146 filamentary cloud taken using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) and its associated polarimeter (POL-2), mounted on the James Clerk Maxwell Telescope, as part of the B-fields In STar forming Regions Observations. This work is aimed at revealing the magnetic field morphology within a core-scale (≲1.0 pc) hub-filament structure (HFS) located at the end of a parsec-scale filament. To investigate whether the observed polarization traces the magnetic field in the HFS, we analyze the dependence between the observed polarization fraction and total intensity using a Bayesian approach with the polarization fraction described by the Rice likelihood function, which can correctly describe the probability density function of the observed polarization fraction for low signal-to-noise ratio data. We find a power-law dependence between the polarization fraction and total intensity with an index of 0.56 in A V ∼ 20–300 mag regions, suggesting that the dust grains in these dense regions can still be aligned with magnetic fields in the IC 5146 regions. Our polarization maps reveal a curved magnetic field, possibly dragged by the contraction along the parsec-scale filament. We further obtain a magnetic field strength of 0.5 ± 0.2 mG toward the central hub using the Davis–Chandrasekhar–Fermi method, corresponding to a mass-to-flux criticality of ∼1.3 ± 0.4 and an Alfvénic Mach number of <0.6. These results suggest that gravity and magnetic field are currently of comparable importance in the HFS and that turbulence is less important.
ALMA Observations of Polarized 872 mum Dust Emission from the Protostellar Systems VLA 1623 and L1527Harris, Robert J.Cox, Erin G.Looney, Leslie W.Li, Zhi-YunYang, HaifengFernández-López, ManuelKwon, WoojinSadavoy, SarahSegura-Cox, DominiqueStephens, IanTobin, JohnDOI: info:10.3847/1538-4357/aac6ecv. 86191
Harris, Robert J., Cox, Erin G., Looney, Leslie W., Li, Zhi-Yun, Yang, Haifeng, Fernández-López, Manuel, Kwon, Woojin, Sadavoy, Sarah, Segura-Cox, Dominique, Stephens, Ian, and Tobin, John. 2018. "ALMA Observations of Polarized 872 mum Dust Emission from the Protostellar Systems VLA 1623 and L1527." The Astrophysical Journal 861:91. https://doi.org/10.3847/1538-4357/aac6ec
ID: 147912
Type: article
Authors: Harris, Robert J.; Cox, Erin G.; Looney, Leslie W.; Li, Zhi-Yun; Yang, Haifeng; Fernández-López, Manuel; Kwon, Woojin; Sadavoy, Sarah; Segura-Cox, Dominique; Stephens, Ian; Tobin, John
Abstract: We present high-sensitivity (sigma I ~ 0.2--0.5 mJy, sigma QU ~ 0.05 mJy), high-resolution (~0."12 -0."2) observations of polarized 872 mum dust emission from the young multiple system VLA 1623 in rho Ophiuchus and the protostar L1527 in Taurus. We detect the circumstellar material of VLA 1623A, the extended Keplerian disk surrounding VLA 1623A that we call VLA 1623CBdisk, VLA 1623B, VLA 1623W, and L1527 strongly in the polarized emission, at the ~1%--3% level. We spatially resolve VLA 1623A into two sources, VLA 1623Aa and VLA 1623Ab, separated by ~30 au and located within a cavity of radius ~50 au within the circumbinary Keplerian disk, as well as the edge-on disk of VLA 1623W. The polarization angle of the emission is uniform across each protostellar source and nearly coincides with each disk's minor axis. The offsets between the minor axis position angle and the polarization angle are not uniformly distributed at the P ≲ 2 × 10-4 level. The circumbinary disk surrounding VLA 1623Aab is azimuthally symmetrically polarized. Each compact source's emission is partially optically thick (tau ≳ 1) at 872 mum, complicating interpretations of polarization involving aligned grains. We find evidence against alignment by radiative flux in each source, particularly in the edge-on VLA 1623W and L1527. We detect astrometric offsets between the polarized emission and the total intensity in VLA 1623Aa, VLA 1623Ab, and VLA 1623B, as predicted if self-scattering in the optically thick limit operates. We conclude that self-scattering is likely responsible for disk-scale polarization at 872 mum in these systems.
Type: article
Authors: Harris, Robert J.; Cox, Erin G.; Looney, Leslie W.; Li, Zhi-Yun; Yang, Haifeng; Fernández-López, Manuel; Kwon, Woojin; Sadavoy, Sarah; Segura-Cox, Dominique; Stephens, Ian; Tobin, John
Abstract: We present high-sensitivity (sigma I ~ 0.2--0.5 mJy, sigma QU ~ 0.05 mJy), high-resolution (~0."12 -0."2) observations of polarized 872 mum dust emission from the young multiple system VLA 1623 in rho Ophiuchus and the protostar L1527 in Taurus. We detect the circumstellar material of VLA 1623A, the extended Keplerian disk surrounding VLA 1623A that we call VLA 1623CBdisk, VLA 1623B, VLA 1623W, and L1527 strongly in the polarized emission, at the ~1%--3% level. We spatially resolve VLA 1623A into two sources, VLA 1623Aa and VLA 1623Ab, separated by ~30 au and located within a cavity of radius ~50 au within the circumbinary Keplerian disk, as well as the edge-on disk of VLA 1623W. The polarization angle of the emission is uniform across each protostellar source and nearly coincides with each disk's minor axis. The offsets between the minor axis position angle and the polarization angle are not uniformly distributed at the P ≲ 2 × 10-4 level. The circumbinary disk surrounding VLA 1623Aab is azimuthally symmetrically polarized. Each compact source's emission is partially optically thick (tau ≳ 1) at 872 mum, complicating interpretations of polarization involving aligned grains. We find evidence against alignment by radiative flux in each source, particularly in the edge-on VLA 1623W and L1527. We detect astrometric offsets between the polarized emission and the total intensity in VLA 1623Aa, VLA 1623Ab, and VLA 1623B, as predicted if self-scattering in the optically thick limit operates. We conclude that self-scattering is likely responsible for disk-scale polarization at 872 mum in these systems.
A First Look at BISTRO Observations of the rho Oph-A coreKwon, JungmiDoi, YasuoTamura, MotohideMatsumura, MasafumiPattle, KateBerry, DavidSadavoy, SarahMatthews, Brenda C.Ward-Thompson, DerekHasegawa, TetsuoFuruya, Ray S.Pon, Andydi Francesco, JamesArzoumanian, DorisHayashi, Saeko S.Kawabata, Koji S.Onaka, TakashiChoi, MinhoKang, MijuHoang, ThiemLee, Chang WonLee, Sang-SungLiu, Hong-LiLiu, TieInutsuka, Shu-ichiroEswaraiah, ChakaliBastien, PierreKwon, WoojinLai, Shih-PingQiu, KepingCoudé, SimonFranzmann, EricaFriberg, PerGraves, Sarah F.Greaves, Jane S.Houde, MartinJohnstone, DougKirk, Jason M.Koch, Patrick M.Li, DiParsons, HarrietRao, RamprasadRawlings, Mark G.Shinnaga, HirokoVan Loo, SvenAso, YusukeByun, Do-YoungChen, Huei-RuChen, Mike C. -YChen, Wen PingChing, Tao-ChungCho, JungyeonChrysostomou, AntonioChung, Eun JungDrabek-Maunder, EmilyEyres, Stewart P. S.Fiege, JasonFriesen, Rachel K.Fuller, GaryGledhill, TimGriffin, Matt J.Gu, QilaoHatchell, JenniferHolland, WayneInoue, TsuyoshiIwasaki, KazunariJeong, Il-GyoKang, Ji-hyunKang, Sung-juKemper, FranciscaKim, GwanjeongKim, JongsooKim, Kee-TaeKim, Kyoung HeeKim, Mi-RyangKim, ShinyoungLacaille, Kevin M.Lee, Jeong-EunLi, DaleiLi, Hua-BaiLiu, JunhaoLiu, Sheng-YuanLyo, A. -RanMairs, SteveMoriarty-Schieven, Gerald H.Nakamura, FumitakaNakanishi, HiroyukiOhashi, NagayoshiPeretto, NicolasPyo, Tae-SooQian, LeiRetter, BrendanRicher, JohnRigby, AndrewRobitaille, Jean-FranoisSavini, GiorgioScaife, Anna M. M.Soam, ArchanaTang, Ya-WenTomisaka, KohjiWang, HongchiWang, Jia-WeiWhitworth, Anthony P.Yen, Hsi-WeiYoo, HyunjuYuan, JinghuaZhang, Chuan-PengZhang, GuoyinZhou, JianjunZhu, LeiAndré, PhilippeDowell, C. DarrenFalle, SamTsukamoto, YusukeNakagawa, TakaoKanamori, YoshihiroKataoka, AkimasaKobayashi, Masato I. N.Nagata, TetsuyaSaito, HiroSeta, MasumichiZenko, TetsuyaDOI: info:10.3847/1538-4357/aabd82v. 8594
Kwon, Jungmi, Doi, Yasuo, Tamura, Motohide, Matsumura, Masafumi, Pattle, Kate, Berry, David, Sadavoy, Sarah, Matthews, Brenda C., Ward-Thompson, Derek, Hasegawa, Tetsuo, Furuya, Ray S., Pon, Andy, di Francesco, James, Arzoumanian, Doris, Hayashi, Saeko S., Kawabata, Koji S., Onaka, Takashi, Choi, Minho, Kang, Miju, Hoang, Thiem, Lee, Chang Won, Lee, Sang-Sung, Liu, Hong-Li, Liu, Tie, Inutsuka, Shu-ichiro et al. 2018. "A First Look at BISTRO Observations of the rho Oph-A core." The Astrophysical Journal 859:4. https://doi.org/10.3847/1538-4357/aabd82
ID: 147424
Type: article
Authors: Kwon, Jungmi; Doi, Yasuo; Tamura, Motohide; Matsumura, Masafumi; Pattle, Kate; Berry, David; Sadavoy, Sarah; Matthews, Brenda C.; Ward-Thompson, Derek; Hasegawa, Tetsuo; Furuya, Ray S.; Pon, Andy; di Francesco, James; Arzoumanian, Doris; Hayashi, Saeko S.; Kawabata, Koji S.; Onaka, Takashi; Choi, Minho; Kang, Miju; Hoang, Thiem; Lee, Chang Won; Lee, Sang-Sung; Liu, Hong-Li; Liu, Tie; Inutsuka, Shu-ichiro; Eswaraiah, Chakali; Bastien, Pierre; Kwon, Woojin; Lai, Shih-Ping; Qiu, Keping; Coudé, Simon; Franzmann, Erica; Friberg, Per; Graves, Sarah F.; Greaves, Jane S.; Houde, Martin; Johnstone, Doug; Kirk, Jason M.; Koch, Patrick M.; Li, Di; Parsons, Harriet; Rao, Ramprasad; Rawlings, Mark G.; Shinnaga, Hiroko; Van Loo, Sven; Aso, Yusuke; Byun, Do-Young; Chen, Huei-Ru; Chen, Mike C. -Y; Chen, Wen Ping; Ching, Tao-Chung; Cho, Jungyeon; Chrysostomou, Antonio; Chung, Eun Jung; Drabek-Maunder, Emily; Eyres, Stewart P. S.; Fiege, Jason; Friesen, Rachel K.; Fuller, Gary; Gledhill, Tim; Griffin, Matt J.; Gu, Qilao; Hatchell, Jennifer; Holland, Wayne; Inoue, Tsuyoshi; Iwasaki, Kazunari; Jeong, Il-Gyo; Kang, Ji-hyun; Kang, Sung-ju; Kemper, Francisca; Kim, Gwanjeong; Kim, Jongsoo; Kim, Kee-Tae; Kim, Kyoung Hee; Kim, Mi-Ryang; Kim, Shinyoung; Lacaille, Kevin M.; Lee, Jeong-Eun; Li, Dalei; Li, Hua-Bai; Liu, Junhao; Liu, Sheng-Yuan; Lyo, A. -Ran; Mairs, Steve; Moriarty-Schieven, Gerald H.; Nakamura, Fumitaka; Nakanishi, Hiroyuki; Ohashi, Nagayoshi; Peretto, Nicolas; Pyo, Tae-Soo; Qian, Lei; Retter, Brendan; Richer, John; Rigby, Andrew; Robitaille, Jean-Franois; Savini, Giorgio; Scaife, Anna M. M.; Soam, Archana; Tang, Ya-Wen; Tomisaka, Kohji; Wang, Hongchi; Wang, Jia-Wei; Whitworth, Anthony P.; Yen, Hsi-Wei; Yoo, Hyunju; Yuan, Jinghua; Zhang, Chuan-Peng; Zhang, Guoyin; Zhou, Jianjun; Zhu, Lei; André, Philippe; Dowell, C. Darren; Falle, Sam; Tsukamoto, Yusuke; Nakagawa, Takao; Kanamori, Yoshihiro; Kataoka, Akimasa; Kobayashi, Masato I. N.; Nagata, Tetsuya; Saito, Hiro; Seta, Masumichi; Zenko, Tetsuya
Abstract: We present 850 mum imaging polarimetry data of the rho Oph-A core taken with the Submillimeter Common-User Bolometer Array-2 (SCUBA-2) and its polarimeter (POL-2) as part of our ongoing survey project, {\boldsymbol{B}}-fields In STar forming RegiOns (BISTRO). The polarization vectors are used to identify the orientation of the magnetic field projected on the plane of the sky at a resolution of 0.01 pc. We identify 10 subregions with distinct polarization fractions and angles in the 0.2 pc rho Oph-A core; some of them can be part of a coherent magnetic field structure in the rho Oph region. The results are consistent with previous observations of the brightest regions of rho Oph-A, where the degrees of polarization are at a level of a few percent, but our data reveal for the first time the magnetic field structures in the fainter regions surrounding the core where the degree of polarization is much higher (>5%). A comparison with previous near-infrared polarimetric data shows that there are several magnetic field components that are consistent at near-infrared and submillimeter wavelengths. Using the Davis--Chandrasekhar--Fermi method, we also derive magnetic field strengths in several subcore regions, which range from approximately 0.2 to 5 mG. We also find a correlation between the magnetic field orientations projected on the sky and the core centroid velocity components.
Type: article
Authors: Kwon, Jungmi; Doi, Yasuo; Tamura, Motohide; Matsumura, Masafumi; Pattle, Kate; Berry, David; Sadavoy, Sarah; Matthews, Brenda C.; Ward-Thompson, Derek; Hasegawa, Tetsuo; Furuya, Ray S.; Pon, Andy; di Francesco, James; Arzoumanian, Doris; Hayashi, Saeko S.; Kawabata, Koji S.; Onaka, Takashi; Choi, Minho; Kang, Miju; Hoang, Thiem; Lee, Chang Won; Lee, Sang-Sung; Liu, Hong-Li; Liu, Tie; Inutsuka, Shu-ichiro; Eswaraiah, Chakali; Bastien, Pierre; Kwon, Woojin; Lai, Shih-Ping; Qiu, Keping; Coudé, Simon; Franzmann, Erica; Friberg, Per; Graves, Sarah F.; Greaves, Jane S.; Houde, Martin; Johnstone, Doug; Kirk, Jason M.; Koch, Patrick M.; Li, Di; Parsons, Harriet; Rao, Ramprasad; Rawlings, Mark G.; Shinnaga, Hiroko; Van Loo, Sven; Aso, Yusuke; Byun, Do-Young; Chen, Huei-Ru; Chen, Mike C. -Y; Chen, Wen Ping; Ching, Tao-Chung; Cho, Jungyeon; Chrysostomou, Antonio; Chung, Eun Jung; Drabek-Maunder, Emily; Eyres, Stewart P. S.; Fiege, Jason; Friesen, Rachel K.; Fuller, Gary; Gledhill, Tim; Griffin, Matt J.; Gu, Qilao; Hatchell, Jennifer; Holland, Wayne; Inoue, Tsuyoshi; Iwasaki, Kazunari; Jeong, Il-Gyo; Kang, Ji-hyun; Kang, Sung-ju; Kemper, Francisca; Kim, Gwanjeong; Kim, Jongsoo; Kim, Kee-Tae; Kim, Kyoung Hee; Kim, Mi-Ryang; Kim, Shinyoung; Lacaille, Kevin M.; Lee, Jeong-Eun; Li, Dalei; Li, Hua-Bai; Liu, Junhao; Liu, Sheng-Yuan; Lyo, A. -Ran; Mairs, Steve; Moriarty-Schieven, Gerald H.; Nakamura, Fumitaka; Nakanishi, Hiroyuki; Ohashi, Nagayoshi; Peretto, Nicolas; Pyo, Tae-Soo; Qian, Lei; Retter, Brendan; Richer, John; Rigby, Andrew; Robitaille, Jean-Franois; Savini, Giorgio; Scaife, Anna M. M.; Soam, Archana; Tang, Ya-Wen; Tomisaka, Kohji; Wang, Hongchi; Wang, Jia-Wei; Whitworth, Anthony P.; Yen, Hsi-Wei; Yoo, Hyunju; Yuan, Jinghua; Zhang, Chuan-Peng; Zhang, Guoyin; Zhou, Jianjun; Zhu, Lei; André, Philippe; Dowell, C. Darren; Falle, Sam; Tsukamoto, Yusuke; Nakagawa, Takao; Kanamori, Yoshihiro; Kataoka, Akimasa; Kobayashi, Masato I. N.; Nagata, Tetsuya; Saito, Hiro; Seta, Masumichi; Zenko, Tetsuya
Abstract: We present 850 mum imaging polarimetry data of the rho Oph-A core taken with the Submillimeter Common-User Bolometer Array-2 (SCUBA-2) and its polarimeter (POL-2) as part of our ongoing survey project, {\boldsymbol{B}}-fields In STar forming RegiOns (BISTRO). The polarization vectors are used to identify the orientation of the magnetic field projected on the plane of the sky at a resolution of 0.01 pc. We identify 10 subregions with distinct polarization fractions and angles in the 0.2 pc rho Oph-A core; some of them can be part of a coherent magnetic field structure in the rho Oph region. The results are consistent with previous observations of the brightest regions of rho Oph-A, where the degrees of polarization are at a level of a few percent, but our data reveal for the first time the magnetic field structures in the fainter regions surrounding the core where the degree of polarization is much higher (>5%). A comparison with previous near-infrared polarimetric data shows that there are several magnetic field components that are consistent at near-infrared and submillimeter wavelengths. Using the Davis--Chandrasekhar--Fermi method, we also derive magnetic field strengths in several subcore regions, which range from approximately 0.2 to 5 mG. We also find a correlation between the magnetic field orientations projected on the sky and the core centroid velocity components.
Hierarchical Fragmentation in the Perseus Molecular Cloud: From the Cloud Scale to Protostellar ObjectsPokhrel, RiwajMyers, Philip C.Dunham, Michael M.Stephens, Ian W.Sadavoy, Sarah I.Zhang, QizhouBourke, Tyler L.Tobin, John J.Lee, Katherine I.Gutermuth, Robert A.Offner, Stella S. R.DOI: info:10.3847/1538-4357/aaa240v. 8535
Pokhrel, Riwaj, Myers, Philip C., Dunham, Michael M., Stephens, Ian W., Sadavoy, Sarah I., Zhang, Qizhou, Bourke, Tyler L., Tobin, John J., Lee, Katherine I., Gutermuth, Robert A., and Offner, Stella S. R. 2018. "Hierarchical Fragmentation in the Perseus Molecular Cloud: From the Cloud Scale to Protostellar Objects." The Astrophysical Journal 853:5. https://doi.org/10.3847/1538-4357/aaa240
ID: 145756
Type: article
Authors: Pokhrel, Riwaj; Myers, Philip C.; Dunham, Michael M.; Stephens, Ian W.; Sadavoy, Sarah I.; Zhang, Qizhou; Bourke, Tyler L.; Tobin, John J.; Lee, Katherine I.; Gutermuth, Robert A.; Offner, Stella S. R.
Abstract: We present a study of hierarchical structure in the Perseus molecular cloud, from the scale of the entire cloud (≳ 10 pc) to smaller clumps (~1 pc), cores (~0.05--0.1 pc), envelopes (~300--3000 au), and protostellar objects (~15 au). We use new observations from the Submillimeter Array (SMA) large project ``Mass Assembly of Stellar Systems and their Evolution with the SMA (MASSES)'' to probe the envelopes, and recent single-dish and interferometric observations from the literature for the remaining scales. This is the first study to analyze hierarchical structure over five scales in the same cloud complex. We compare the number of fragments with the number of Jeans masses in each scale to calculate the Jeans efficiency, or the ratio of observed to expected number of fragments. The velocity dispersion is assumed to arise either from purely thermal motions or from combined thermal and non-thermal motions inferred from observed spectral line widths. For each scale, thermal Jeans fragmentation predicts more fragments than observed, corresponding to inefficient thermal Jeans fragmentation. For the smallest scale, thermal plus non-thermal Jeans fragmentation also predicts too many protostellar objects. However, at each of the larger scales thermal plus non-thermal Jeans fragmentation predicts fewer than one fragment, corresponding to no fragmentation into envelopes, cores, and clumps. Over all scales, the results are inconsistent with complete Jeans fragmentation based on either thermal or thermal plus non-thermal motions. They are more nearly consistent with inefficient thermal Jeans fragmentation, where the thermal Jeans efficiency increases from the largest to the smallest scale.
Type: article
Authors: Pokhrel, Riwaj; Myers, Philip C.; Dunham, Michael M.; Stephens, Ian W.; Sadavoy, Sarah I.; Zhang, Qizhou; Bourke, Tyler L.; Tobin, John J.; Lee, Katherine I.; Gutermuth, Robert A.; Offner, Stella S. R.
Abstract: We present a study of hierarchical structure in the Perseus molecular cloud, from the scale of the entire cloud (≳ 10 pc) to smaller clumps (~1 pc), cores (~0.05--0.1 pc), envelopes (~300--3000 au), and protostellar objects (~15 au). We use new observations from the Submillimeter Array (SMA) large project ``Mass Assembly of Stellar Systems and their Evolution with the SMA (MASSES)'' to probe the envelopes, and recent single-dish and interferometric observations from the literature for the remaining scales. This is the first study to analyze hierarchical structure over five scales in the same cloud complex. We compare the number of fragments with the number of Jeans masses in each scale to calculate the Jeans efficiency, or the ratio of observed to expected number of fragments. The velocity dispersion is assumed to arise either from purely thermal motions or from combined thermal and non-thermal motions inferred from observed spectral line widths. For each scale, thermal Jeans fragmentation predicts more fragments than observed, corresponding to inefficient thermal Jeans fragmentation. For the smallest scale, thermal plus non-thermal Jeans fragmentation also predicts too many protostellar objects. However, at each of the larger scales thermal plus non-thermal Jeans fragmentation predicts fewer than one fragment, corresponding to no fragmentation into envelopes, cores, and clumps. Over all scales, the results are inconsistent with complete Jeans fragmentation based on either thermal or thermal plus non-thermal motions. They are more nearly consistent with inefficient thermal Jeans fragmentation, where the thermal Jeans efficiency increases from the largest to the smallest scale.
Intensity-corrected Herschel Observations of Nearby Isolated Low-mass CloudsSadavoy, Sarah I.Keto, EricBourke, Tyler L.Dunham, Michael M.Myers, Philip C.Stephens, Ian W.di Francesco, JamesWebb, KristiStutz, Amelia M.Launhardt, RalfTobin, John J.DOI: info:10.3847/1538-4357/aaa080v. 852102
Sadavoy, Sarah I., Keto, Eric, Bourke, Tyler L., Dunham, Michael M., Myers, Philip C., Stephens, Ian W., di Francesco, James, Webb, Kristi, Stutz, Amelia M., Launhardt, Ralf, and Tobin, John J. 2018. "Intensity-corrected Herschel Observations of Nearby Isolated Low-mass Clouds." The Astrophysical Journal 852:102. https://doi.org/10.3847/1538-4357/aaa080
ID: 145763
Type: article
Authors: Sadavoy, Sarah I.; Keto, Eric; Bourke, Tyler L.; Dunham, Michael M.; Myers, Philip C.; Stephens, Ian W.; di Francesco, James; Webb, Kristi; Stutz, Amelia M.; Launhardt, Ralf; Tobin, John J.
Abstract: We present intensity-corrected Herschel maps at 100, 160, 250, 350, and 500 mum for 56 isolated low-mass clouds. We determine the zero-point corrections for Herschel Photodetector Array Camera and Spectrometer (PACS) and Spectral Photometric Imaging Receiver (SPIRE) maps from the Herschel Science Archive (HSA) using Planck data. Since these HSA maps are small, we cannot correct them using typical methods. Here we introduce a technique to measure the zero-point corrections for small Herschel maps. We use radial profiles to identify offsets between the observed HSA intensities and the expected intensities from Planck. Most clouds have reliable offset measurements with this technique. In addition, we find that roughly half of the clouds have underestimated HSA-SPIRE intensities in their outer envelopes relative to Planck, even though the HSA-SPIRE maps were previously zero-point corrected. Using our technique, we produce corrected Herschel intensity maps for all 56 clouds and determine their line-of-sight average dust temperatures and optical depths from modified blackbody fits. The clouds have typical temperatures of ~14--20 K and optical depths of ~10-5--10-3. Across the whole sample, we find an anticorrelation between temperature and optical depth. We also find lower temperatures than what was measured in previous Herschel studies, which subtracted out a background level from their intensity maps to circumvent the zero-point correction. Accurate Herschel observations of clouds are key to obtaining accurate density and temperature profiles. To make such future analyses possible, intensity-corrected maps for all 56 clouds are publicly available in the electronic version. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Type: article
Authors: Sadavoy, Sarah I.; Keto, Eric; Bourke, Tyler L.; Dunham, Michael M.; Myers, Philip C.; Stephens, Ian W.; di Francesco, James; Webb, Kristi; Stutz, Amelia M.; Launhardt, Ralf; Tobin, John J.
Abstract: We present intensity-corrected Herschel maps at 100, 160, 250, 350, and 500 mum for 56 isolated low-mass clouds. We determine the zero-point corrections for Herschel Photodetector Array Camera and Spectrometer (PACS) and Spectral Photometric Imaging Receiver (SPIRE) maps from the Herschel Science Archive (HSA) using Planck data. Since these HSA maps are small, we cannot correct them using typical methods. Here we introduce a technique to measure the zero-point corrections for small Herschel maps. We use radial profiles to identify offsets between the observed HSA intensities and the expected intensities from Planck. Most clouds have reliable offset measurements with this technique. In addition, we find that roughly half of the clouds have underestimated HSA-SPIRE intensities in their outer envelopes relative to Planck, even though the HSA-SPIRE maps were previously zero-point corrected. Using our technique, we produce corrected Herschel intensity maps for all 56 clouds and determine their line-of-sight average dust temperatures and optical depths from modified blackbody fits. The clouds have typical temperatures of ~14--20 K and optical depths of ~10-5--10-3. Across the whole sample, we find an anticorrelation between temperature and optical depth. We also find lower temperatures than what was measured in previous Herschel studies, which subtracted out a background level from their intensity maps to circumvent the zero-point correction. Accurate Herschel observations of clouds are key to obtaining accurate density and temperature profiles. To make such future analyses possible, intensity-corrected maps for all 56 clouds are publicly available in the electronic version. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Dust Polarization toward Embedded Protostars in Ophiuchus with ALMA. II. IRAS 16293-2422Sadavoy, Sarah I.Myers, Philip C.Stephens, Ian W.Tobin, JohnKwon, WoojinSegura-Cox, DominiqueHenning, ThomasCommerçon, BenoîtLooney, LeslieDOI: info:10.3847/1538-4357/aaef81v. 869115
Sadavoy, Sarah I., Myers, Philip C., Stephens, Ian W., Tobin, John, Kwon, Woojin, Segura-Cox, Dominique, Henning, Thomas, Commerçon, Benoît, and Looney, Leslie. 2018. "Dust Polarization toward Embedded Protostars in Ophiuchus with ALMA. II. IRAS 16293-2422." The Astrophysical Journal 869:115. https://doi.org/10.3847/1538-4357/aaef81
ID: 150217
Type: article
Authors: Sadavoy, Sarah I.; Myers, Philip C.; Stephens, Ian W.; Tobin, John; Kwon, Woojin; Segura-Cox, Dominique; Henning, Thomas; Commerçon, Benoît; Looney, Leslie
Abstract: We present high-resolution (∼35 au) ALMA Band 6 1.3 mm dust polarization observations of IRAS 16293. These observations spatially resolve the dust polarization across the two protostellar sources and toward the filamentary structures between them. The dust polarization and inferred magnetic field have complicated structures throughout the region. In particular, we find that the magnetic field is aligned parallel to three filamentary structures. We characterize the physical properties of the filamentary structure that bridges IRAS 16293A and IRAS 16293B and estimate a magnetic field strength of 23–78 mG using the Davis-Chandrasekhar-Fermi method. We construct a toy model for the bridge material assuming that the young stars dominate the mass and gravitational potential of the system. We find that the expected gas flow to each star is of comparable order to the Alfvén speed, which suggests that the field may be regulating the gas flow. We also find that the bridging material should be depleted in ∼103 yr. If the bridge is part of the natal filament that formed the stars, then it must have accreted new material. Alternatively, the bridge could be a transient structure. Finally, we show that the 1.3 mm polarization morphology of the optically thick IRAS 16293B system is qualitatively similar to dust self-scattering. Based on similar polarization measurements at 6.9 mm, we propose that IRAS 16293B has produced a substantial population of large dust grains with sizes between 200 and 2000 μm.
Type: article
Authors: Sadavoy, Sarah I.; Myers, Philip C.; Stephens, Ian W.; Tobin, John; Kwon, Woojin; Segura-Cox, Dominique; Henning, Thomas; Commerçon, Benoît; Looney, Leslie
Abstract: We present high-resolution (∼35 au) ALMA Band 6 1.3 mm dust polarization observations of IRAS 16293. These observations spatially resolve the dust polarization across the two protostellar sources and toward the filamentary structures between them. The dust polarization and inferred magnetic field have complicated structures throughout the region. In particular, we find that the magnetic field is aligned parallel to three filamentary structures. We characterize the physical properties of the filamentary structure that bridges IRAS 16293A and IRAS 16293B and estimate a magnetic field strength of 23–78 mG using the Davis-Chandrasekhar-Fermi method. We construct a toy model for the bridge material assuming that the young stars dominate the mass and gravitational potential of the system. We find that the expected gas flow to each star is of comparable order to the Alfvén speed, which suggests that the field may be regulating the gas flow. We also find that the bridging material should be depleted in ∼103 yr. If the bridge is part of the natal filament that formed the stars, then it must have accreted new material. Alternatively, the bridge could be a transient structure. Finally, we show that the 1.3 mm polarization morphology of the optically thick IRAS 16293B system is qualitatively similar to dust self-scattering. Based on similar polarization measurements at 6.9 mm, we propose that IRAS 16293B has produced a substantial population of large dust grains with sizes between 200 and 2000 μm.
Magnetic Fields toward Ophiuchus-B Derived from SCUBA-2 Polarization MeasurementsSoam, ArchanaPattle, KateWard-Thompson, DerekLee, Chang WonSadavoy, SarahKoch, Patrick M.Kim, GwanjeongKwon, JungmiKwon, WoojinArzoumanian, DorisBerry, DavidHoang, ThiemTamura, MotohideLee, Sang-SungLiu, TieKim, Kee-TaeJohnstone, DougNakamura, FumitakaLyo, A. -RanOnaka, TakashiKim, JongsooFuruya, Ray S.Hasegawa, TetsuoLai, Shih-PingBastien, PierreChung, Eun JungKim, ShinyoungParsons, HarrietRawlings, Mark G.Mairs, SteveGraves, Sarah F.Robitaille, Jean-FranoisLiu, Hong-LiWhitworth, Anthony P.Eswaraiah, ChakaliRao, RamprasadYoo, HyunjuHoude, MartinKang, Ji-hyunDoi, YasuoChoi, MinhoKang, MijuCoudé, SimonLi, Hua-BaiMatsumura, MasafumiMatthews, Brenda C.Pon, Andydi Francesco, JamesHayashi, Saeko S.Kawabata, Koji S.Inutsuka, Shu-ichiroQiu, KepingFranzmann, EricaFriberg, PerGreaves, Jane S.Kirk, Jason M.Li, DiShinnaga, HirokoVan Loo, SvenAso, YusukeByun, Do-YoungChen, Huei-RuChen, Mike C. -YChen, Wen PingChing, Tao-ChungCho, JungyeonChrysostomou, AntonioDrabek-Maunder, EmilyEyres, Stewart P. S.Fiege, JasonFriesen, Rachel K.Fuller, GaryGledhill, TimGriffin, Matt J.Gu, QilaoHatchell, JenniferHolland, WayneInoue, TsuyoshiIwasaki, KazunariJeong, Il-GyoKang, Sung-juKemper, FranciscaKim, Kyoung HeeKim, Mi-RyangLacaille, Kevin M.Lee, Jeong-EunLi, DaleiLiu, JunhaoLiu, Sheng-YuanMoriarty-Schieven, Gerald H.Nakanishi, HiroyukiOhashi, NagayoshiPeretto, NicolasPyo, Tae-SooQian, LeiRetter, BrendanRicher, JohnRigby, AndrewSavini, GiorgioScaife, Anna M. M.Tang, Ya-WenTomisaka, KohjiWang, HongchiWang, Jia-WeiYen, Hsi-WeiYuan, JinghuaZhang, Chuan-PengZhang, GuoyinZhou, JianjunZhu, LeiAndré, PhilippeDowell, C. DarrenFalle, SamTsukamoto, YusukeKanamori, YoshihiroKataoka, AkimasaKobayashi, Masato I. N.Nagata, TetsuyaSaito, HiroSeta, MasumichiHwang, JihyeHan, IlseungLee, HyeseungZenko, TetsuyaDOI: info:10.3847/1538-4357/aac4a6v. 86165
Soam, Archana, Pattle, Kate, Ward-Thompson, Derek, Lee, Chang Won, Sadavoy, Sarah, Koch, Patrick M., Kim, Gwanjeong, Kwon, Jungmi, Kwon, Woojin, Arzoumanian, Doris, Berry, David, Hoang, Thiem, Tamura, Motohide, Lee, Sang-Sung, Liu, Tie, Kim, Kee-Tae, Johnstone, Doug, Nakamura, Fumitaka, Lyo, A. -Ran, Onaka, Takashi, Kim, Jongsoo, Furuya, Ray S., Hasegawa, Tetsuo, Lai, Shih-Ping, Bastien, Pierre et al. 2018. "Magnetic Fields toward Ophiuchus-B Derived from SCUBA-2 Polarization Measurements." The Astrophysical Journal 861:65. https://doi.org/10.3847/1538-4357/aac4a6
ID: 147915
Type: article
Authors: Soam, Archana; Pattle, Kate; Ward-Thompson, Derek; Lee, Chang Won; Sadavoy, Sarah; Koch, Patrick M.; Kim, Gwanjeong; Kwon, Jungmi; Kwon, Woojin; Arzoumanian, Doris; Berry, David; Hoang, Thiem; Tamura, Motohide; Lee, Sang-Sung; Liu, Tie; Kim, Kee-Tae; Johnstone, Doug; Nakamura, Fumitaka; Lyo, A. -Ran; Onaka, Takashi; Kim, Jongsoo; Furuya, Ray S.; Hasegawa, Tetsuo; Lai, Shih-Ping; Bastien, Pierre; Chung, Eun Jung; Kim, Shinyoung; Parsons, Harriet; Rawlings, Mark G.; Mairs, Steve; Graves, Sarah F.; Robitaille, Jean-Franois; Liu, Hong-Li; Whitworth, Anthony P.; Eswaraiah, Chakali; Rao, Ramprasad; Yoo, Hyunju; Houde, Martin; Kang, Ji-hyun; Doi, Yasuo; Choi, Minho; Kang, Miju; Coudé, Simon; Li, Hua-Bai; Matsumura, Masafumi; Matthews, Brenda C.; Pon, Andy; di Francesco, James; Hayashi, Saeko S.; Kawabata, Koji S.; Inutsuka, Shu-ichiro; Qiu, Keping; Franzmann, Erica; Friberg, Per; Greaves, Jane S.; Kirk, Jason M.; Li, Di; Shinnaga, Hiroko; Van Loo, Sven; Aso, Yusuke; Byun, Do-Young; Chen, Huei-Ru; Chen, Mike C. -Y; Chen, Wen Ping; Ching, Tao-Chung; Cho, Jungyeon; Chrysostomou, Antonio; Drabek-Maunder, Emily; Eyres, Stewart P. S.; Fiege, Jason; Friesen, Rachel K.; Fuller, Gary; Gledhill, Tim; Griffin, Matt J.; Gu, Qilao; Hatchell, Jennifer; Holland, Wayne; Inoue, Tsuyoshi; Iwasaki, Kazunari; Jeong, Il-Gyo; Kang, Sung-ju; Kemper, Francisca; Kim, Kyoung Hee; Kim, Mi-Ryang; Lacaille, Kevin M.; Lee, Jeong-Eun; Li, Dalei; Liu, Junhao; Liu, Sheng-Yuan; Moriarty-Schieven, Gerald H.; Nakanishi, Hiroyuki; Ohashi, Nagayoshi; Peretto, Nicolas; Pyo, Tae-Soo; Qian, Lei; Retter, Brendan; Richer, John; Rigby, Andrew; Savini, Giorgio; Scaife, Anna M. M.; Tang, Ya-Wen; Tomisaka, Kohji; Wang, Hongchi; Wang, Jia-Wei; Yen, Hsi-Wei; Yuan, Jinghua; Zhang, Chuan-Peng; Zhang, Guoyin; Zhou, Jianjun; Zhu, Lei; André, Philippe; Dowell, C. Darren; Falle, Sam; Tsukamoto, Yusuke; Kanamori, Yoshihiro; Kataoka, Akimasa; Kobayashi, Masato I. N.; Nagata, Tetsuya; Saito, Hiro; Seta, Masumichi; Hwang, Jihye; Han, Ilseung; Lee, Hyeseung; Zenko, Tetsuya
Abstract: We present the results of dust emission polarization measurements of Ophiuchus-B (Oph-B) carried out using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) camera with its associated polarimeter (POL-2) on the James Clerk Maxwell Telescope in Hawaii. This work is part of the B-fields in Star-forming Region Observations survey initiated to understand the role of magnetic fields in star formation for nearby star-forming molecular clouds. We present a first look at the geometry and strength of magnetic fields in Oph-B. The field geometry is traced over ~0.2 pc, with clear detection of both of the sub-clumps of Oph-B. The field pattern appears significantly disordered in sub-clump Oph-B1. The field geometry in Oph-B2 is more ordered, with a tendency to be along the major axis of the clump, parallel to the filamentary structure within which it lies. The degree of polarization decreases systematically toward the dense core material in the two sub-clumps. The field lines in the lower density material along the periphery are smoothly joined to the large-scale magnetic fields probed by NIR polarization observations. We estimated a magnetic field strength of 630 ± 410 muG in the Oph-B2 sub-clump using a Davis--Chandrasekhar--Fermi analysis. With this magnetic field strength, we find a mass-to-flux ratio lambda = 1.6 ± 1.1, which suggests that the Oph-B2 clump is slightly magnetically supercritical.
Type: article
Authors: Soam, Archana; Pattle, Kate; Ward-Thompson, Derek; Lee, Chang Won; Sadavoy, Sarah; Koch, Patrick M.; Kim, Gwanjeong; Kwon, Jungmi; Kwon, Woojin; Arzoumanian, Doris; Berry, David; Hoang, Thiem; Tamura, Motohide; Lee, Sang-Sung; Liu, Tie; Kim, Kee-Tae; Johnstone, Doug; Nakamura, Fumitaka; Lyo, A. -Ran; Onaka, Takashi; Kim, Jongsoo; Furuya, Ray S.; Hasegawa, Tetsuo; Lai, Shih-Ping; Bastien, Pierre; Chung, Eun Jung; Kim, Shinyoung; Parsons, Harriet; Rawlings, Mark G.; Mairs, Steve; Graves, Sarah F.; Robitaille, Jean-Franois; Liu, Hong-Li; Whitworth, Anthony P.; Eswaraiah, Chakali; Rao, Ramprasad; Yoo, Hyunju; Houde, Martin; Kang, Ji-hyun; Doi, Yasuo; Choi, Minho; Kang, Miju; Coudé, Simon; Li, Hua-Bai; Matsumura, Masafumi; Matthews, Brenda C.; Pon, Andy; di Francesco, James; Hayashi, Saeko S.; Kawabata, Koji S.; Inutsuka, Shu-ichiro; Qiu, Keping; Franzmann, Erica; Friberg, Per; Greaves, Jane S.; Kirk, Jason M.; Li, Di; Shinnaga, Hiroko; Van Loo, Sven; Aso, Yusuke; Byun, Do-Young; Chen, Huei-Ru; Chen, Mike C. -Y; Chen, Wen Ping; Ching, Tao-Chung; Cho, Jungyeon; Chrysostomou, Antonio; Drabek-Maunder, Emily; Eyres, Stewart P. S.; Fiege, Jason; Friesen, Rachel K.; Fuller, Gary; Gledhill, Tim; Griffin, Matt J.; Gu, Qilao; Hatchell, Jennifer; Holland, Wayne; Inoue, Tsuyoshi; Iwasaki, Kazunari; Jeong, Il-Gyo; Kang, Sung-ju; Kemper, Francisca; Kim, Kyoung Hee; Kim, Mi-Ryang; Lacaille, Kevin M.; Lee, Jeong-Eun; Li, Dalei; Liu, Junhao; Liu, Sheng-Yuan; Moriarty-Schieven, Gerald H.; Nakanishi, Hiroyuki; Ohashi, Nagayoshi; Peretto, Nicolas; Pyo, Tae-Soo; Qian, Lei; Retter, Brendan; Richer, John; Rigby, Andrew; Savini, Giorgio; Scaife, Anna M. M.; Tang, Ya-Wen; Tomisaka, Kohji; Wang, Hongchi; Wang, Jia-Wei; Yen, Hsi-Wei; Yuan, Jinghua; Zhang, Chuan-Peng; Zhang, Guoyin; Zhou, Jianjun; Zhu, Lei; André, Philippe; Dowell, C. Darren; Falle, Sam; Tsukamoto, Yusuke; Kanamori, Yoshihiro; Kataoka, Akimasa; Kobayashi, Masato I. N.; Nagata, Tetsuya; Saito, Hiro; Seta, Masumichi; Hwang, Jihye; Han, Ilseung; Lee, Hyeseung; Zenko, Tetsuya
Abstract: We present the results of dust emission polarization measurements of Ophiuchus-B (Oph-B) carried out using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) camera with its associated polarimeter (POL-2) on the James Clerk Maxwell Telescope in Hawaii. This work is part of the B-fields in Star-forming Region Observations survey initiated to understand the role of magnetic fields in star formation for nearby star-forming molecular clouds. We present a first look at the geometry and strength of magnetic fields in Oph-B. The field geometry is traced over ~0.2 pc, with clear detection of both of the sub-clumps of Oph-B. The field pattern appears significantly disordered in sub-clump Oph-B1. The field geometry in Oph-B2 is more ordered, with a tendency to be along the major axis of the clump, parallel to the filamentary structure within which it lies. The degree of polarization decreases systematically toward the dense core material in the two sub-clumps. The field lines in the lower density material along the periphery are smoothly joined to the large-scale magnetic fields probed by NIR polarization observations. We estimated a magnetic field strength of 630 ± 410 muG in the Oph-B2 sub-clump using a Davis--Chandrasekhar--Fermi analysis. With this magnetic field strength, we find a mass-to-flux ratio lambda = 1.6 ± 1.1, which suggests that the Oph-B2 clump is slightly magnetically supercritical.
Mass Assembly of Stellar Systems and Their Evolution with the SMA (MASSES)---1.3 mm Subcompact Data ReleaseStephens, Ian W.Dunham, Michael M.Myers, Philip C.Pokhrel, RiwajBourke, Tyler L.Vorobyov, Eduard I.Tobin, John J.Sadavoy, Sarah I.Pineda, Jaime E.Offner, Stella S. R.Lee, Katherine I.Kristensen, Lars E.Jørgensen, Jes K.Goodman, Alyssa A.Arce, Héctor G.Gurwell, MarkDOI: info:10.3847/1538-4365/aacda9v. 23722
Stephens, Ian W., Dunham, Michael M., Myers, Philip C., Pokhrel, Riwaj, Bourke, Tyler L., Vorobyov, Eduard I., Tobin, John J., Sadavoy, Sarah I., Pineda, Jaime E., Offner, Stella S. R., Lee, Katherine I., Kristensen, Lars E., Jørgensen, Jes K., Goodman, Alyssa A., Arce, Héctor G., and Gurwell, Mark. 2018. "Mass Assembly of Stellar Systems and Their Evolution with the SMA (MASSES)---1.3 mm Subcompact Data Release." The Astrophysical Journal Supplement Series 237:22. https://doi.org/10.3847/1538-4365/aacda9
ID: 148980
Type: article
Authors: Stephens, Ian W.; Dunham, Michael M.; Myers, Philip C.; Pokhrel, Riwaj; Bourke, Tyler L.; Vorobyov, Eduard I.; Tobin, John J.; Sadavoy, Sarah I.; Pineda, Jaime E.; Offner, Stella S. R.; Lee, Katherine I.; Kristensen, Lars E.; Jørgensen, Jes K.; Goodman, Alyssa A.; Arce, Héctor G.; Gurwell, Mark
Abstract: We present the Mass Assembly of Stellar Systems and their Evolution with the SMA (MASSES) survey, which uses the Submillimeter Array (SMA) interferometer to map the continuum and molecular lines for all 74 known Class 0/I protostellar systems in the Perseus molecular cloud. The primary goal of the survey is to observe an unbiased sample of young protostars in a single molecular cloud so that we can characterize the evolution of protostars. This paper releases the MASSES 1.3 mm data from the subcompact configuration (˜4" or ˜1000 au resolution), which is the SMA's most compact array configuration. We release both uv visibility data and imaged data for the spectral lines CO(2-1), 13CO(2-1), C18O(2-1), and N2D+(3-2), as well as for the 1.3 mm continuum. We identify the tracers that are detected toward each source. We also show example images of continuum and CO(2-1) outflows, analyze C18O(2-1) spectra, and present data from the SVS 13 star-forming region. The calculated envelope masses from the continuum show a decreasing trend with bolometric temperature (a proxy for age). Typical C18O(2-1) line widths are 1.45 km s-1, which is higher than the C18O line widths detected toward Perseus filaments and cores. We find that N2D+(3-2) is significantly more likely to be detected toward younger protostars. We show that the protostars in SVS 13 are contained within filamentary structures as traced by C18O(2-1) and N2D+(3-2). We also present the locations of SVS 13A's high-velocity (absolute line-of-sight velocities >150 km s-1) red and blue outflow components. Data can be downloaded from https://dataverse.harvard.edu/dataverse/MASSES.
Type: article
Authors: Stephens, Ian W.; Dunham, Michael M.; Myers, Philip C.; Pokhrel, Riwaj; Bourke, Tyler L.; Vorobyov, Eduard I.; Tobin, John J.; Sadavoy, Sarah I.; Pineda, Jaime E.; Offner, Stella S. R.; Lee, Katherine I.; Kristensen, Lars E.; Jørgensen, Jes K.; Goodman, Alyssa A.; Arce, Héctor G.; Gurwell, Mark
Abstract: We present the Mass Assembly of Stellar Systems and their Evolution with the SMA (MASSES) survey, which uses the Submillimeter Array (SMA) interferometer to map the continuum and molecular lines for all 74 known Class 0/I protostellar systems in the Perseus molecular cloud. The primary goal of the survey is to observe an unbiased sample of young protostars in a single molecular cloud so that we can characterize the evolution of protostars. This paper releases the MASSES 1.3 mm data from the subcompact configuration (˜4" or ˜1000 au resolution), which is the SMA's most compact array configuration. We release both uv visibility data and imaged data for the spectral lines CO(2-1), 13CO(2-1), C18O(2-1), and N2D+(3-2), as well as for the 1.3 mm continuum. We identify the tracers that are detected toward each source. We also show example images of continuum and CO(2-1) outflows, analyze C18O(2-1) spectra, and present data from the SVS 13 star-forming region. The calculated envelope masses from the continuum show a decreasing trend with bolometric temperature (a proxy for age). Typical C18O(2-1) line widths are 1.45 km s-1, which is higher than the C18O line widths detected toward Perseus filaments and cores. We find that N2D+(3-2) is significantly more likely to be detected toward younger protostars. We show that the protostars in SVS 13 are contained within filamentary structures as traced by C18O(2-1) and N2D+(3-2). We also present the locations of SVS 13A's high-velocity (absolute line-of-sight velocities >150 km s-1) red and blue outflow components. Data can be downloaded from https://dataverse.harvard.edu/dataverse/MASSES.
An Estimation of the Star Formation Rate in the Perseus ComplexMercimek, SeymaMyers, Philip C.Lee, Katherine I.Sadavoy, Sarah I.DOI: info:10.3847/1538-3881/aa661fv. 153214
Mercimek, Seyma, Myers, Philip C., Lee, Katherine I., and Sadavoy, Sarah I. 2017. "An Estimation of the Star Formation Rate in the Perseus Complex." The Astronomical Journal 153:214. https://doi.org/10.3847/1538-3881/aa661f
ID: 143337
Type: article
Authors: Mercimek, Seyma; Myers, Philip C.; Lee, Katherine I.; Sadavoy, Sarah I.
Abstract: We present the results of our investigation of the star-forming potential in the Perseus star-forming complex. We build on previous starless core, protostellar core, and young stellar object (YSO) catalogs from Spitzer (3.6-70 ?m), Herschel (70-500 ?m), and SCUBA (850 ?m) observations in the literature. We place the cores and YSOs within seven star-forming clumps based on column densities greater than 5× {10}21 cm-2. We calculate the mean density and free-fall time for 69 starless cores as ~5.55 × {10}-19 g cm-3 and ~0.1 Myr, respectively, and we estimate the star formation rate for the near future as ~150 M ? Myr-1. According to Bonnor-Ebert stability analysis, we find that majority of starless cores in Perseus are unstable. Broadly, these cores can collapse to form the next generation of stars. We found a relation between starless cores and YSOs, where the numbers of young protostars (Class 0 + Class I) are similar to the numbers of starless cores. This similarity, which shows a one-to-one relation, suggests that these starless cores may form the next generation of stars with approximately the same formation rate as the current generation, as identified by the Class 0 and Class I protostars. It follows that if such a relation between starless cores and any YSO stage exists, the SFR values of these two populations must be nearly constant. In brief, we propose that this one-to-one relation is an important factor in better understanding the star formation process within a cloud.
Type: article
Authors: Mercimek, Seyma; Myers, Philip C.; Lee, Katherine I.; Sadavoy, Sarah I.
Abstract: We present the results of our investigation of the star-forming potential in the Perseus star-forming complex. We build on previous starless core, protostellar core, and young stellar object (YSO) catalogs from Spitzer (3.6-70 ?m), Herschel (70-500 ?m), and SCUBA (850 ?m) observations in the literature. We place the cores and YSOs within seven star-forming clumps based on column densities greater than 5× {10}21 cm-2. We calculate the mean density and free-fall time for 69 starless cores as ~5.55 × {10}-19 g cm-3 and ~0.1 Myr, respectively, and we estimate the star formation rate for the near future as ~150 M ? Myr-1. According to Bonnor-Ebert stability analysis, we find that majority of starless cores in Perseus are unstable. Broadly, these cores can collapse to form the next generation of stars. We found a relation between starless cores and YSOs, where the numbers of young protostars (Class 0 + Class I) are similar to the numbers of starless cores. This similarity, which shows a one-to-one relation, suggests that these starless cores may form the next generation of stars with approximately the same formation rate as the current generation, as identified by the Class 0 and Class I protostars. It follows that if such a relation between starless cores and any YSO stage exists, the SFR values of these two populations must be nearly constant. In brief, we propose that this one-to-one relation is an important factor in better understanding the star formation process within a cloud.
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