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Showing 1-20 of about 38 results.
A Hard Look at Local, Optically Selected, Obscured Seyfert GalaxiesKammoun, E. S.Miller, J. M.Koss, M.Oh, K.Zoghbi, A.Mushotzky, R. F.Barret, D.Behar, E.Brandt, W. N.Brenneman, Laura W.Kaastra, J. S.Lohfink, A. M.Proga, D.Stern, D.DOI: info:10.3847/1538-4357/abb29fv. 901161
Kammoun, E. S., Miller, J. M., Koss, M., Oh, K., Zoghbi, A., Mushotzky, R. F., Barret, D., Behar, E., Brandt, W. N., Brenneman, Laura W., Kaastra, J. S., Lohfink, A. M., Proga, D., and Stern, D. 2020. "A Hard Look at Local, Optically Selected, Obscured Seyfert Galaxies." The Astrophysical Journal 901:161. https://doi.org/10.3847/1538-4357/abb29f
ID: 157611
Type: article
Authors: Kammoun, E. S.; Miller, J. M.; Koss, M.; Oh, K.; Zoghbi, A.; Mushotzky, R. F.; Barret, D.; Behar, E.; Brandt, W. N.; Brenneman, Laura W.; Kaastra, J. S.; Lohfink, A. M.; Proga, D.; Stern, D.
Abstract: We study the X-ray spectra of a sample of 19 obscured, optically selected Seyfert galaxies (Sy 1.8, 1.9, and 2) in the local universe (d ≤ 175 Mpc), drawn from the CfA Seyfert sample. Our analysis is driven by the high sensitivity of NuSTAR in the hard X-rays, coupled with soft X-ray spectra using XMM-Newton, Chandra, Suzaku, and Swift/XRT. We also analyze the optical spectra of these sources in order to obtain accurate mass estimates and Eddington fractions. We employ four different models to analyze the X-ray spectra of these sources, which all provide consistent results. We find that 79%-90% of the sources are heavily obscured with line-of-sight column density NH > 1023 cm-2. We also find a Compton-thick (NH > 1024 cm-2) fraction of 37%-53%. These results are consistent with previous estimates based on multiwavelength analyses. We find that the fraction of reprocessed to intrinsic emission is positively correlated with NH and negatively correlated with the intrinsic, unabsorbed X-ray luminosity (in agreement with the Iwasawa-Taniguchi effect). Our results support the hypothesis that radiation pressure regulates the distribution of the circumnuclear material. * Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under program ID 099.A-0403.
An Obscured, Seyfert 2-like State of the Stellar-mass Black Hole GRS 1915+105 Caused by Failed Disk WindsMiller, J. M.Zoghbi, A.Raymond, JohnBalakrishnan, M.Brenneman, LauraCackett, E.Draghis, P.Fabian, A. C.Gallo, E.Kaastra, J.Kallman, T.Kammoun, E.Motta, S. E.Proga, D.Reynolds, M. T.Trueba, N.DOI: info:10.3847/1538-4357/abbb31v. 90430
Miller, J. M., Zoghbi, A., Raymond, John, Balakrishnan, M., Brenneman, Laura, Cackett, E., Draghis, P., Fabian, A. C., Gallo, E., Kaastra, J., Kallman, T., Kammoun, E., Motta, S. E., Proga, D., Reynolds, M. T., and Trueba, N. 2020. "An Obscured, Seyfert 2-like State of the Stellar-mass Black Hole GRS 1915+105 Caused by Failed Disk Winds." The Astrophysical Journal 904:30. https://doi.org/10.3847/1538-4357/abbb31
ID: 158752
Type: article
Authors: Miller, J. M.; Zoghbi, A.; Raymond, John; Balakrishnan, M.; Brenneman, Laura; Cackett, E.; Draghis, P.; Fabian, A. C.; Gallo, E.; Kaastra, J.; Kallman, T.; Kammoun, E.; Motta, S. E.; Proga, D.; Reynolds, M. T.; Trueba, N.
Abstract: We report on Chandra grating spectra of the stellar-mass black hole GRS 1915+105 obtained during a novel, highly obscured state. As the source entered this state, a dense, massive accretion disk wind was detected through strong absorption lines. Photoionization modeling indicates that it must originate close to the central engine, orders of magnitude from the outer accretion disk. Strong, nearly sinusoidal flux variability in this phase yielded a key insight: the wind is blueshifted when its column density is relatively low, but redshifted as it approaches the Compton-thick threshold. At no point does the wind appear to achieve the local escape velocity; in this sense, it is a "failed wind." Later observations suggest that the disk ultimately fails to keep even the central engine clear of gas, leading to heavily obscured and Compton-thick states characterized by very strong Fe K emission lines. Indeed, these later spectra are successfully described using models developed for obscured active galactic nuclei (AGNs). We discuss our results in terms of the remarkable similarity of GRS 1915+105 deep in its "obscured state" to Seyfert 2 and Compton-thick AGNs, and we explore how our understanding of accretion and obscuration in massive black holes is impacted by our observations.
A Hard Look at NGC 5347: Revealing a Nearby Compton-thick AGNKammoun, E. S.Miller, J. M.Zoghbi, A.Oh, K.Koss, M.Mushotzky, R. F.Brenneman, Laura W.Brandt, W. N.Proga, D.Lohfink, A. M.Kaastra, J. S.Barret, D.Behar, E.Stern, D.DOI: info:10.3847/1538-4357/ab1c5fv. 877102
Kammoun, E. S., Miller, J. M., Zoghbi, A., Oh, K., Koss, M., Mushotzky, R. F., Brenneman, Laura W., Brandt, W. N., Proga, D., Lohfink, A. M., Kaastra, J. S., Barret, D., Behar, E., and Stern, D. 2019. "A Hard Look at NGC 5347: Revealing a Nearby Compton-thick AGN." The Astrophysical Journal 877:102. https://doi.org/10.3847/1538-4357/ab1c5f
ID: 152887
Type: article
Authors: Kammoun, E. S.; Miller, J. M.; Zoghbi, A.; Oh, K.; Koss, M.; Mushotzky, R. F.; Brenneman, Laura W.; Brandt, W. N.; Proga, D.; Lohfink, A. M.; Kaastra, J. S.; Barret, D.; Behar, E.; Stern, D.
Abstract: Current measurements show that the observed fraction of Compton-thick (CT) active galactic nuclei (AGN) is smaller than the expected values needed to explain the cosmic X-ray background. Prior fits to the X-ray spectrum of the nearby Seyfert-2 galaxy NGC 5347 (z = 0.00792, D = 35.5 Mpc ) have alternately suggested a CT and Compton-thin source. Combining archival data from Suzaku, Chandra, and—most importantly—new data from NuSTAR, and using three distinct families of models, we show that NGC 5347 is an obscured CTAGN (N H > 2.23 × 1024 cm‑2). Its 2–30 keV spectrum is dominated by reprocessed emission from distant material, characterized by a strong Fe Kα line and a Compton hump. We found a large equivalent width of the Fe Kα line (EW = 2.3 ± 0.3 keV) and a high intrinsic-to-observed flux ratio (∼100). All of these observations are typical for bona fide CTAGN. We estimate a bolometric luminosity of L bol ≃ 0.014 ± 0.005 L Edd.. The Chandra image of NGC 5347 reveals the presence of extended emission dominating the soft X-ray spectrum (E < 2 keV), which coincides with the [O III] emission detected in Hubble Space Telescope images. Comparison to other CTAGN suggests that NGC 5347 is broadly consistent with the average properties of this source class. We simulated XRISM and Athena/X-IFU spectra of the source, showing the potential of these future missions in identifying CTAGN in the soft X-rays.
The Nature of the Broadband X-Ray Variability in the Dwarf Seyfert Galaxy NGC 4395Kammoun, E. S.Nardini, E.Zoghbi, A.Miller, J. M.Cackett, E. M.Gallo, E.Reynolds, M. T.Risaliti, G.Barret, D.Brandt, W. N.Brenneman, L. W.Kaastra, J. S.Koss, M.Lohfink, A. M.Mushotzky, R. F.Raymond, JohnStern, D.DOI: info:10.3847/1538-4357/ab5110v. 886145
Kammoun, E. S., Nardini, E., Zoghbi, A., Miller, J. M., Cackett, E. M., Gallo, E., Reynolds, M. T., Risaliti, G., Barret, D., Brandt, W. N., Brenneman, L. W., Kaastra, J. S., Koss, M., Lohfink, A. M., Mushotzky, R. F., Raymond, John, and Stern, D. 2019. "The Nature of the Broadband X-Ray Variability in the Dwarf Seyfert Galaxy NGC 4395." The Astrophysical Journal 886:145. https://doi.org/10.3847/1538-4357/ab5110
ID: 154511
Type: article
Authors: Kammoun, E. S.; Nardini, E.; Zoghbi, A.; Miller, J. M.; Cackett, E. M.; Gallo, E.; Reynolds, M. T.; Risaliti, G.; Barret, D.; Brandt, W. N.; Brenneman, L. W.; Kaastra, J. S.; Koss, M.; Lohfink, A. M.; Mushotzky, R. F.; Raymond, John; Stern, D.
Abstract: We present a flux-resolved X-ray analysis of the dwarf Seyfert 1.8 galaxy NGC 4395, based on three archival XMM-Newton and one archival NuSTAR observations. The source is known to harbor a low-mass black hole (∼ {10}4{--}{{a}} {few} × {10}5 {M}ȯ ) and shows strong variability in the full X-ray range during these observations. We model the flux-resolved spectra of the source assuming three absorbing layers: neutral, mildly ionized, and highly ionized ({N}{{H}}∼ 1.6× {10}22{--}3.4× {10}23 {cm}}-2, ∼ 0.8{--}7.8× {10}22 {cm}}-2, and 3.8 × 1022 cm−2, respectively). The source also shows intrinsic variability by a factor of ∼3 on short timescales, which is due to changes in the nuclear flux, assumed to be a power law (Γ = 1.6─1.67). Our results show a positive correlation between the intrinsic flux and the absorbers' ionization parameter. The covering fraction of the neutral absorber varies during the first XMM-Newton observation, which could explain the pronounced soft X-ray variability. However, the source remains fully covered by this layer during the other two observations, largely suppressing the soft X-ray variability. This suggests an inhomogeneous and layered structure in the broad-line region. We also find a difference in the characteristic timescale of the power spectra between different energy ranges and observations. We finally show simulated spectra with XRISM, eXTP, and Athena, which will allow us to characterize the different absorbers, study their dynamics, and will help us identify their locations and sizes.
General Physical Properties of Gamma-Ray-emitting Narrow-line Seyfert 1 GalaxiesPaliya, Vaidehi S.Parker, M. L.Jiang, J.Fabian, A. C.Brenneman, LauraAjello, M.Hartmann, D.DOI: info:10.3847/1538-4357/ab01cev. 872169
Paliya, Vaidehi S., Parker, M. L., Jiang, J., Fabian, A. C., Brenneman, Laura, Ajello, M., and Hartmann, D. 2019. "General Physical Properties of Gamma-Ray-emitting Narrow-line Seyfert 1 Galaxies." The Astrophysical Journal 872:169. https://doi.org/10.3847/1538-4357/ab01ce
ID: 150519
Type: article
Authors: Paliya, Vaidehi S.; Parker, M. L.; Jiang, J.; Fabian, A. C.; Brenneman, Laura; Ajello, M.; Hartmann, D.
Abstract: We present the results of a detailed multiwavelength study of a sample of 16 narrow-line Seyfert 1 (NLSy1) galaxies known in γ-rays so far. This includes a focused X-ray spectral analysis, to compare them with a more general NLSy1 population, and a broadband spectral energy distribution (SED) modeling considering the leptonic radiative processes to understand their similarity/dissimilarity with blazars. The X-ray spectra of γ-NLSy1 galaxies exhibit similarities to both typical NLSy1 sources below ≲2 keV and blazars at higher energies. We also find weak evidences of excess absorption in the soft X-ray spectra of three sources and a tentative detection of the Fe line in 1H 0323+342. A comparison of the broadband parameters derived from the SED modeling reveals the similarity of γ-NLSy1 objects to blazars, in particular to flat-spectrum radio quasars. The γ-NLS1 galaxies host relatively low power jets with small bulk Lorentz factors with respect to blazars, and this explains the paucity of such sources in the γ-ray catalogs and identification of even fewer parent population members. Many of the observed features of these intriguing objects suggest that they host low-mass black holes. The accretion rate in Eddington units can be considered as the driving factor to explain the physical properties of γ-NLSy1 sources, similar to that which is known for the general blazar population.
Detection of polarized gamma-ray emission from the Crab nebula with the Hitomi Soft Gamma-ray DetectorHitomi CollaborationAharonian, FelixAkamatsu, HirokiAkimoto, FumieAllen, Steven W.Angelini, LorellaAudard, MarcAwaki, HisamitsuAxelsson, MagnusBamba, AyaBautz, Marshall W.Blandford, RogerBrenneman, Laura W.Brown, Gregory V.Bulbul, EsraCackett, Edward M.Chernyakova, MariaChiao, Meng P.Coppi, Paolo S.Costantini, Elisade Plaa, Jellede Vries, Cor P.den Herder, Jan-WillemDone, ChrisDotani, TadayasuEbisawa, KenEckart, Megan E.Enoto, TeruakiEzoe, YuichiroFabian, Andrew C.Ferrigno, CarloFoster, Adam R.Fujimoto, RyuichiFukazawa, YasushiFuruzawa, AkihiroGaleazzi, MassimilianoGallo, Luigi C.Gandhi, PoshakGiustini, MargheritaGoldwurm, AndreaGu, LiyiGuainazzi, MatteoHaba, YoshitoHagino, KouichiHamaguchi, KenjiHarrus, Ilana M.Hatsukade, IsamuHayashi, KatsuhiroHayashi, TakayukiHayashida, KiyoshiHiraga, Junko S.Hornschemeier, AnnHoshino, AkioHughes, John P.Ichinohe, YutoIizuka, RyoInoue, HajimeInoue, YoshiyukiIshida, ManabuIshikawa, KumiIshisaki, YoshitakaIwai, MasachikaKaastra, JelleKallman, TimKamae, TsuneyoshiKataoka, JunKatsuda, SatoruKawai, NobuyukiKelley, Richard L.Kilbourne, Caroline A.Kitaguchi, TakaoKitamoto, ShunjiKitayama, TetsuKohmura, TakayoshiKokubun, MotohideKoyama, KatsujiKoyama, ShuKretschmar, PeterKrimm, Hans A.Kubota, AyaKunieda, HideyoLaurent, PhilippeLee, Shiu-HangLeutenegger, Maurice A.Limousin, OlivierLoewenstein, MichaelLong, Knox S.Lumb, DavidMadejski, GregMaeda, YoshitomoMaier, DanielMakishima, KazuoMarkevitch, MaximMatsumoto, HironoriMatsushita, KyokoMcCammon, DanMcNamara, Brian R.Mehdipour, MissaghMiller, Eric D.Miller, Jon M.Mineshige, ShinMitsuda, KazuhisaMitsuishi, IkuyukiMiyazawa, TakuyaMizuno, TsunefumiMori, HideyukiMori, KojiMukai, KojiMurakami, HiroshiMushotzky, Richard F.Nakagawa, TakaoNakajima, HiroshiNakamori, TakeshiNakashima, ShinyaNakazawa, KazuhiroNobukawa, Kumiko K.Nobukawa, MasayoshiNoda, HirofumiOdaka, HirokazuOhashi, TakayaOhno, MasanoriOkajima, TakashiOta, NaomiOzaki, MasanobuPaerels, FritsPaltani, StéphanePetre, RobertPinto, CiroPorter, Frederick S.Pottschmidt, KatjaReynolds, Christopher S.Safi-Harb, SamarSaito, ShinyaSakai, KazuhiroSasaki, ToruSato, GoroSato, KosukeSato, RieSawada, MakotoSchartel, NorbertSerlemtsos, Peter J.Seta, HiromiShidatsu, MegumiSimionescu, AuroraSmith, Randall K.Soong, YangStawarz, ŁukaszSugawara, YasuharuSugita, SatoshiSzymkowiak, AndrewTajima, HiroyasuTakahashi, HiromitsuTakahashi, TadayukiTakeda, Shin'ichiroTakei, YohTamagawa, ToruTamura, TakayukiTanaka, TakaakiTanaka, YasuoTanaka, Yasuyuki T.Tashiro, Makoto S.Tawara, YuzuruTerada, YukikatsuTerashima, YuichiTombesi, FrancescoTomida, HiroshiTsuboi, YohkoTsujimoto, MasahiroTsunemi, HiroshiTsuru, Takeshi GoUchida, HiroyukiUchiyama, HidekiUchiyama, YasunobuUeda, ShutaroUeda, YoshihiroUno, Shin'ichiroUrry, C. MeganUrsino, EugenioWatanabe, ShinWerner, NorbertWilkins, Dan R.Williams, Brian J.Yamada, ShinyaYamaguchi, HiroyaYamaoka, KazutakaYamasaki, Noriko Y.Yamauchi, MakotoYamauchi, ShigeoYaqoob, TahirYatsu, YoichiYonetoku, DaisukeZhuravleva, IrinaZoghbi, AbderahmenUchida, YuusukeDOI: info:10.1093/pasj/psy118v. 70113
Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., den Herder, Jan-Willem, Done, Chris, Dotani, Tadayasu et al. 2018. "Detection of polarized gamma-ray emission from the Crab nebula with the Hitomi Soft Gamma-ray Detector." Publications of the Astronomical Society of Japan 70:113. https://doi.org/10.1093/pasj/psy118
ID: 150195
Type: article
Authors: Hitomi Collaboration; Aharonian, Felix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steven W.; Angelini, Lorella; Audard, Marc; Awaki, Hisamitsu; Axelsson, Magnus; Bamba, Aya; Bautz, Marshall W.; Blandford, Roger; Brenneman, Laura W.; Brown, Gregory V.; Bulbul, Esra; Cackett, Edward M.; Chernyakova, Maria; Chiao, Meng P.; Coppi, Paolo S.; Costantini, Elisa; de Plaa, Jelle; de Vries, Cor P.; den Herder, Jan-Willem; Done, Chris; Dotani, Tadayasu; Ebisawa, Ken; Eckart, Megan E.; Enoto, Teruaki; Ezoe, Yuichiro; Fabian, Andrew C.; Ferrigno, Carlo; Foster, Adam R.; Fujimoto, Ryuichi; Fukazawa, Yasushi; Furuzawa, Akihiro; Galeazzi, Massimiliano; Gallo, Luigi C.; Gandhi, Poshak; Giustini, Margherita; Goldwurm, Andrea; Gu, Liyi; Guainazzi, Matteo; Haba, Yoshito; Hagino, Kouichi; Hamaguchi, Kenji; Harrus, Ilana M.; Hatsukade, Isamu; Hayashi, Katsuhiro; Hayashi, Takayuki; Hayashida, Kiyoshi; Hiraga, Junko S.; Hornschemeier, Ann; Hoshino, Akio; Hughes, John P.; Ichinohe, Yuto; Iizuka, Ryo; Inoue, Hajime; Inoue, Yoshiyuki; Ishida, Manabu; Ishikawa, Kumi; Ishisaki, Yoshitaka; Iwai, Masachika; Kaastra, Jelle; Kallman, Tim; Kamae, Tsuneyoshi; Kataoka, Jun; Katsuda, Satoru; Kawai, Nobuyuki; Kelley, Richard L.; Kilbourne, Caroline A.; Kitaguchi, Takao; Kitamoto, Shunji; Kitayama, Tetsu; Kohmura, Takayoshi; Kokubun, Motohide; Koyama, Katsuji; Koyama, Shu; Kretschmar, Peter; Krimm, Hans A.; Kubota, Aya; Kunieda, Hideyo; Laurent, Philippe; Lee, Shiu-Hang; Leutenegger, Maurice A.; Limousin, Olivier; Loewenstein, Michael; Long, Knox S.; Lumb, David; Madejski, Greg; Maeda, Yoshitomo; Maier, Daniel; Makishima, Kazuo; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian R.; Mehdipour, Missagh; Miller, Eric D.; Miller, Jon M.; Mineshige, Shin; Mitsuda, Kazuhisa; Mitsuishi, Ikuyuki; Miyazawa, Takuya; Mizuno, Tsunefumi; Mori, Hideyuki; Mori, Koji; Mukai, Koji; Murakami, Hiroshi; Mushotzky, Richard F.; Nakagawa, Takao; Nakajima, Hiroshi; Nakamori, Takeshi; Nakashima, Shinya; Nakazawa, Kazuhiro; Nobukawa, Kumiko K.; Nobukawa, Masayoshi; Noda, Hirofumi; Odaka, Hirokazu; Ohashi, Takaya; Ohno, Masanori; Okajima, Takashi; Ota, Naomi; Ozaki, Masanobu; Paerels, Frits; Paltani, Stéphane; Petre, Robert; Pinto, Ciro; Porter, Frederick S.; Pottschmidt, Katja; Reynolds, Christopher S.; Safi-Harb, Samar; Saito, Shinya; Sakai, Kazuhiro; Sasaki, Toru; Sato, Goro; Sato, Kosuke; Sato, Rie; Sawada, Makoto; Schartel, Norbert; Serlemtsos, Peter J.; Seta, Hiromi; Shidatsu, Megumi; Simionescu, Aurora; Smith, Randall K.; Soong, Yang; Stawarz, Łukasz; Sugawara, Yasuharu; Sugita, Satoshi; Szymkowiak, Andrew; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shin'ichiro; Takei, Yoh; Tamagawa, Toru; Tamura, Takayuki; Tanaka, Takaaki; Tanaka, Yasuo; Tanaka, Yasuyuki T.; Tashiro, Makoto S.; Tawara, Yuzuru; Terada, Yukikatsu; Terashima, Yuichi; Tombesi, Francesco; Tomida, Hiroshi; Tsuboi, Yohko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi Go; Uchida, Hiroyuki; Uchiyama, Hideki; Uchiyama, Yasunobu; Ueda, Shutaro; Ueda, Yoshihiro; Uno, Shin'ichiro; Urry, C. Megan; Ursino, Eugenio; Watanabe, Shin; Werner, Norbert; Wilkins, Dan R.; Williams, Brian J.; Yamada, Shinya; Yamaguchi, Hiroya; Yamaoka, Kazutaka; Yamasaki, Noriko Y.; Yamauchi, Makoto; Yamauchi, Shigeo; Yaqoob, Tahir; Yatsu, Yoichi; Yonetoku, Daisuke; Zhuravleva, Irina; Zoghbi, Abderahmen; Uchida, Yuusuke
Abstract: We present the results from the Hitomi Soft Gamma-ray Detector (SGD) observation of the Crab nebula. The main part of SGD is a Compton camera, which in addition to being a spectrometer, is capable of measuring polarization of gamma-ray photons. The Crab nebula is one of the brightest X-ray/gamma-ray sources on the sky, and the only source from which polarized X-ray photons have been detected. SGD observed the Crab nebula during the initial test observation phase of Hitomi. We performed data analysis of the SGD observation, SGD background estimation, and SGD Monte Carlo simulations, and successfully detected polarized gamma-ray emission from the Crab nebula with only about 5 ks exposure time. The obtained polarization fraction of the phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1% ± 10.6%), and the polarization angle is {110{^{circ}.}7} +{13{^{circ}.}2}/-{13{^{circ}.}0} in the energy range of 60-160 keV (the errors correspond to the 1 σ deviation). The confidence level of the polarization detection was 99.3%. The polarization angle measured by SGD is about one sigma deviation with the projected spin axis of the pulsar, {124{^{circ}.}0} ± {0{^{circ}.}1}.
X-Ray Structure between the Innermost Disk and Optical Broad-line Region in NGC 4151Miller, J. M.Cackett, E.Zoghbi, A.Barret, D.Behar, E.Brenneman, L. W.Fabian, A. C.Kaastra, J. S.Lohfink, A.Mushotzky, R. F.Nandra, K.Raymond, J.DOI: info:10.3847/1538-4357/aadbaav. 86597
Miller, J. M., Cackett, E., Zoghbi, A., Barret, D., Behar, E., Brenneman, L. W., Fabian, A. C., Kaastra, J. S., Lohfink, A., Mushotzky, R. F., Nandra, K., and Raymond, J. 2018. "X-Ray Structure between the Innermost Disk and Optical Broad-line Region in NGC 4151." The Astrophysical Journal 865:97. https://doi.org/10.3847/1538-4357/aadbaa
ID: 149400
Type: article
Authors: Miller, J. M.; Cackett, E.; Zoghbi, A.; Barret, D.; Behar, E.; Brenneman, L. W.; Fabian, A. C.; Kaastra, J. S.; Lohfink, A.; Mushotzky, R. F.; Nandra, K.; Raymond, J.
Abstract: We present an analysis of the narrow Fe Kα line in Chandra/HETGS observations of the Seyfert active galactic nucleus (AGN) NGC 4151. The sensitivity and resolution afforded by the gratings reveal asymmetry in this line. Models including weak Doppler boosting, gravitational redshifts, and scattering are generally preferred over Gaussians at the 5σ level of confidence, and generally measure radii consistent with R≃ 500{--}1000 {{GM}}BH}/{c}2. Separate fits to “high/unobscured” and “low/obscured” phases reveal that the line originates at smaller radii in high-flux states; model-independent tests indicate that this effect is significant at the 4–5σ level. Some models and Δt ≃ 2 × 104 s variations in line flux suggest that the narrow Fe Kα line may originate at radii as small as R≃ 50{--}130 {{GM}}BH}/{c}2 in high-flux states. These results indicate that the narrow Fe Kα line in NGC 4151 is primarily excited in the innermost part of the optical broad line region (BLR), or X-ray BLR. Alternatively, a warp could provide the solid angle needed to enhance Fe Kα line emission from intermediate radii, and might resolve an apparent discrepancy in the inclination of the innermost and outer disk in NGC 4151. Both warps and the BLR may originate through radiation pressure, so these explanations may be linked. We discuss our results in detail, and consider the potential for future observations with Chandra, XARM, and ATHENA to measure black hole masses and to study the intermediate disk in AGNs using narrow Fe Kα emission lines.
NuSTAR spectral analysis of two bright Seyfert 1 galaxies: MCG +8-11-11 and NGC 6814Tortosa, A.Bianchi, S.Marinucci, A.Matt, G.Middei, R.Piconcelli, E.Brenneman, L. W.Cappi, M.Dadina, M.de Rosa, A.Petrucci, P. O.Ursini, F.Walton, D. J.DOI: info:10.1093/mnras/stx2457v. 4733104–3112
Tortosa, A., Bianchi, S., Marinucci, A., Matt, G., Middei, R., Piconcelli, E., Brenneman, L. W., Cappi, M., Dadina, M., de Rosa, A., Petrucci, P. O., Ursini, F., and Walton, D. J. 2018. "NuSTAR spectral analysis of two bright Seyfert 1 galaxies: MCG +8-11-11 and NGC 6814." Monthly Notices of the Royal Astronomical Society 473:3104– 3112. https://doi.org/10.1093/mnras/stx2457
ID: 145742
Type: article
Authors: Tortosa, A.; Bianchi, S.; Marinucci, A.; Matt, G.; Middei, R.; Piconcelli, E.; Brenneman, L. W.; Cappi, M.; Dadina, M.; de Rosa, A.; Petrucci, P. O.; Ursini, F.; Walton, D. J.
Abstract: We report on the NuSTAR observations of two bright Seyfert 1 galaxies, namely MCG +8-11-11 (100 ks) and NGC 6814 (150 ks). The main goal of these observations was to investigate the Comptonization mechanisms acting in the innermost regions of an active galactic nucleus (AGN) which are believed to be responsible for the UV/X-ray emission. The spectroscopic analysis of the NuSTAR spectra of these two sources revealed that although they had different properties overall (black hole masses, luminosity and Eddington ratios), they had very similar coronal properties. Both presented a power-law spectrum with a high-energy cut-off at ~150-200 keV, a relativistically broadened Fe K alpha line and the associated disc reflection component, plus a narrow iron line likely emitted in Compton thin and distant matter. The intrinsic continuum was well described by Comptonization models that show for MCG +8-11-11 a temperature of the coronal plasma of kTe ~ 60 keV and an extrapolated optical depth tau = 1.8; for NGC 6814, the coronal temperature was kTe ~ 45 keV with an extrapolated optical depth of tau = 2.5. We compare and discuss these values to some most common Comptonization models that aim at explaining the energy production and stability of coronae in AGNs.
Hitomi Constraints on the 3.5 keV Line in the Perseus Galaxy ClusterAharonian, F. A.Akamatsu, H.Akimoto, F.Allen, S. W.Angelini, L.Arnaud, K. A.Audard, M.Awaki, H.Axelsson, M.Bamba, A.Bautz, M. W.Blandford, R. D.Bulbul, E.Brenneman, L. W.Brown, G. V.Cackett, E. M.Chernyakova, M.Chiao, M. P.Coppi, P.Costantini, E.de Plaa, J.den Herder, J. -WDone, C.Dotani, T.Ebisawa, K.Eckart, M. E.Enoto, T.Ezoe, Y.Fabian, A. C.Ferrigno, C.Foster, A. R.Fujimoto, R.Fukazawa, Y.Furuzawa, A.Galeazzi, M.Gallo, L. C.Gandhi, P.Giustini, M.Goldwurm, A.Gu, L.Guainazzi, M.Haba, Y.Hagino, K.Hamaguchi, K.Harrus, I.Hatsukade, I.Hayashi, K.Hayashi, T.Hayashida, K.Hiraga, J.Hornschemeier, A. E.Hoshino, A.Hughes, J. P.Ichinohe, Y.Iizuka, R.Inoue, H.Inoue, S.Inoue, Y.Ishibashi, K.Ishida, M.Ishikawa, K.Ishisaki, Y.Itoh, M.Iwai, M.Iyomoto, N.Kaastra, J. S.Kallman, T.Kamae, T.Kara, E.Kataoka, J.Katsuda, S.Katsuta, J.Kawaharada, M.Kawai, N.Kelley, R. L.Khangulyan, D.Kilbourne, C. A.King, A. L.Kitaguchi, T.Kitamoto, S.Kitayama, T.Kohmura, T.Kokubun, M.Koyama, S.Koyama, K.Kretschmar, P.Krimm, H. A.Kubota, A.Kunieda, H.Laurent, P.Lebrun, F.Lee, S. -HLeutenegger, M. A.Limousin, O.Loewenstein, M.Long, K. S.Lumb, D. H.Madejski, G. M.Maeda, Y.Maier, D.Makishima, K.Markevitch, M.Matsumoto, H.Matsushita, K.McCammon, D.McNamara, B. R.Mehdipour, M.Miller, E. D.Miller, J. M.Mineshige, S.Mitsuda, K.Mitsuishi, I.Miyazawa, T.Mizuno, T.Mori, H.Mori, K.Moseley, H.Mukai, K.Murakami, H.Murakami, T.Mushotzky, R. F.Nakagawa, T.Nakajima, H.Nakamori, T.Nakano, T.Nakashima, S.Nakazawa, K.Nobukawa, K.Nobukawa, M.Noda, H.Nomachi, M.O'Dell, S. L.Odaka, H.Ohashi, T.Ohno, M.Okajima, T.Ota, N.Ozaki, M.Paerels, F.Paltani, S.Parmar, A.Petre, R.Pinto, C.Pohl, M.Porter, F. S.Pottschmidt, K.Ramsey, B. D.Reynolds, C. S.Russell, H. R.Safi-Harb, S.Saito, S.Sakai, K.Sameshima, H.Sasaki, T.Sato, G.Sato, K.Sato, R.Sawada, M.Schartel, N.Serlemitsos, P. J.Seta, H.Shidatsu, M.Simionescu, A.Smith, R. K.Soong, Y.Stawarz, Ł.Sugawara, Y.Sugita, S.Szymkowiak, A. E.Tajima, H.Takahashi, H.Takahashi, T.Takeda, S.Takei, Y.Tamagawa, T.Tamura, K.Tamura, T.Tanaka, T.Tanaka, YasuoTanaka, YasuyukiTashiro, M.Tawara, Y.Terada, Y.Terashima, Y.Tombesi, F.Tomida, H.Tsuboi, Y.Tsujimoto, M.Tsunemi, H.Tsuru, T.Uchida, H.Uchiyama, H.Uchiyama, Y.Ueda, S.Ueda, Y.Ueno, S.Uno, S.Urry, C. M.Ursino, E.de Vries, C. P.Watanabe, S.Werner, N.Wik, D. R.Wilkins, D. R.Williams, B. J.Yamada, S.Yamaguchi, H.Yamaoka, K.Yamasaki, N. Y.Yamauchi, M.Yamauchi, S.Yaqoob, T.Yatsu, Y.Yonetoku, D.Yoshida, A.Zhuravleva, I.Zoghbi, A.Hitomi CollaborationDOI: info:10.3847/2041-8213/aa61fav. 837L15
Aharonian, F. A., Akamatsu, H., Akimoto, F., Allen, S. W., Angelini, L., Arnaud, K. A., Audard, M., Awaki, H., Axelsson, M., Bamba, A., Bautz, M. W., Blandford, R. D., Bulbul, E., Brenneman, L. W., Brown, G. V., Cackett, E. M., Chernyakova, M., Chiao, M. P., Coppi, P., Costantini, E., de Plaa, J., den Herder, J. -W, Done, C., Dotani, T., Ebisawa, K. et al. 2017. "Hitomi Constraints on the 3.5 keV Line in the Perseus Galaxy Cluster." Astrophysical Journal Letters 837:L15. https://doi.org/10.3847/2041-8213/aa61fa
ID: 142851
Type: article
Authors: Aharonian, F. A.; Akamatsu, H.; Akimoto, F.; Allen, S. W.; Angelini, L.; Arnaud, K. A.; Audard, M.; Awaki, H.; Axelsson, M.; Bamba, A.; Bautz, M. W.; Blandford, R. D.; Bulbul, E.; Brenneman, L. W.; Brown, G. V.; Cackett, E. M.; Chernyakova, M.; Chiao, M. P.; Coppi, P.; Costantini, E.; de Plaa, J.; den Herder, J. -W; Done, C.; Dotani, T.; Ebisawa, K.; Eckart, M. E.; Enoto, T.; Ezoe, Y.; Fabian, A. C.; Ferrigno, C.; Foster, A. R.; Fujimoto, R.; Fukazawa, Y.; Furuzawa, A.; Galeazzi, M.; Gallo, L. C.; Gandhi, P.; Giustini, M.; Goldwurm, A.; Gu, L.; Guainazzi, M.; Haba, Y.; Hagino, K.; Hamaguchi, K.; Harrus, I.; Hatsukade, I.; Hayashi, K.; Hayashi, T.; Hayashida, K.; Hiraga, J.; Hornschemeier, A. E.; Hoshino, A.; Hughes, J. P.; Ichinohe, Y.; Iizuka, R.; Inoue, H.; Inoue, S.; Inoue, Y.; Ishibashi, K.; Ishida, M.; Ishikawa, K.; Ishisaki, Y.; Itoh, M.; Iwai, M.; Iyomoto, N.; Kaastra, J. S.; Kallman, T.; Kamae, T.; Kara, E.; Kataoka, J.; Katsuda, S.; Katsuta, J.; Kawaharada, M.; Kawai, N.; Kelley, R. L.; Khangulyan, D.; Kilbourne, C. A.; King, A. L.; Kitaguchi, T.; Kitamoto, S.; Kitayama, T.; Kohmura, T.; Kokubun, M.; Koyama, S.; Koyama, K.; Kretschmar, P.; Krimm, H. A.; Kubota, A.; Kunieda, H.; Laurent, P.; Lebrun, F.; Lee, S. -H; Leutenegger, M. A.; Limousin, O.; Loewenstein, M.; Long, K. S.; Lumb, D. H.; Madejski, G. M.; Maeda, Y.; Maier, D.; Makishima, K.; Markevitch, M.; Matsumoto, H.; Matsushita, K.; McCammon, D.; McNamara, B. R.; Mehdipour, M.; Miller, E. D.; Miller, J. M.; Mineshige, S.; Mitsuda, K.; Mitsuishi, I.; Miyazawa, T.; Mizuno, T.; Mori, H.; Mori, K.; Moseley, H.; Mukai, K.; Murakami, H.; Murakami, T.; Mushotzky, R. F.; Nakagawa, T.; Nakajima, H.; Nakamori, T.; Nakano, T.; Nakashima, S.; Nakazawa, K.; Nobukawa, K.; Nobukawa, M.; Noda, H.; Nomachi, M.; O'Dell, S. L.; Odaka, H.; Ohashi, T.; Ohno, M.; Okajima, T.; Ota, N.; Ozaki, M.; Paerels, F.; Paltani, S.; Parmar, A.; Petre, R.; Pinto, C.; Pohl, M.; Porter, F. S.; Pottschmidt, K.; Ramsey, B. D.; Reynolds, C. S.; Russell, H. R.; Safi-Harb, S.; Saito, S.; Sakai, K.; Sameshima, H.; Sasaki, T.; Sato, G.; Sato, K.; Sato, R.; Sawada, M.; Schartel, N.; Serlemitsos, P. J.; Seta, H.; Shidatsu, M.; Simionescu, A.; Smith, R. K.; Soong, Y.; Stawarz, Ł.; Sugawara, Y.; Sugita, S.; Szymkowiak, A. E.; Tajima, H.; Takahashi, H.; Takahashi, T.; Takeda, S.; Takei, Y.; Tamagawa, T.; Tamura, K.; Tamura, T.; Tanaka, T.; Tanaka, Yasuo; Tanaka, Yasuyuki; Tashiro, M.; Tawara, Y.; Terada, Y.; Terashima, Y.; Tombesi, F.; Tomida, H.; Tsuboi, Y.; Tsujimoto, M.; Tsunemi, H.; Tsuru, T.; Uchida, H.; Uchiyama, H.; Uchiyama, Y.; Ueda, S.; Ueda, Y.; Ueno, S.; Uno, S.; Urry, C. M.; Ursino, E.; de Vries, C. P.; Watanabe, S.; Werner, N.; Wik, D. R.; Wilkins, D. R.; Williams, B. J.; Yamada, S.; Yamaguchi, H.; Yamaoka, K.; Yamasaki, N. Y.; Yamauchi, M.; Yamauchi, S.; Yaqoob, T.; Yatsu, Y.; Yonetoku, D.; Yoshida, A.; Zhuravleva, I.; Zoghbi, A.; Hitomi Collaboration
Abstract: High-resolution X-ray spectroscopy with Hitomi was expected to resolve the origin of the faint unidentified E≈ 3.5 {keV} emission line reported in several low-resolution studies of various massive systems, such as galaxies and clusters, including the Perseus cluster. We have analyzed the Hitomi first-light observation of the Perseus cluster. The emission line expected for Perseus based on the XMM-Newton signal from the large cluster sample under the dark matter decay scenario is too faint to be detectable in the Hitomi data. However, the previously reported 3.5 keV flux from Perseus was anomalously high compared to the sample-based prediction. We find no unidentified line at the reported high flux level. Taking into account the XMM measurement uncertainties for this region, the inconsistency with Hitomi is at a 99% significance for a broad dark matter line and at 99.7% for a narrow line from the gas. We do not find anomalously high fluxes of the nearby faint K line or the Ar satellite line that were proposed as explanations for the earlier 3.5 keV detections. We do find a hint of a broad excess near the energies of high-n transitions of S xvi (E≃ 3.44 {keV} rest-frame)—a possible signature of charge exchange in the molecular nebula and another proposed explanation for the unidentified line. While its energy is consistent with XMM pn detections, it is unlikely to explain the MOS signal. A confirmation of this interesting feature has to wait for a more sensitive observation with a future calorimeter experiment.
A Suzaku, NuSTAR, and XMM-Newton view on variable absorption and relativistic reflection in NGC 4151Beuchert, T.Markowitz, A. G.Dauser, T.García, J. A.Keck, M. L.Wilms, J.Kadler, M.Brenneman, L. W.Zdziarski, A. A.DOI: info:10.1051/0004-6361/201630293v. 603A50
Beuchert, T., Markowitz, A. G., Dauser, T., García, J. A., Keck, M. L., Wilms, J., Kadler, M., Brenneman, L. W., and Zdziarski, A. A. 2017. "A Suzaku, NuSTAR, and XMM-Newton view on variable absorption and relativistic reflection in NGC 4151." Astronomy and Astrophysics 603:A50. https://doi.org/10.1051/0004-6361/201630293
ID: 143840
Type: article
Authors: Beuchert, T.; Markowitz, A. G.; Dauser, T.; García, J. A.; Keck, M. L.; Wilms, J.; Kadler, M.; Brenneman, L. W.; Zdziarski, A. A.
Abstract: We disentangle X-ray disk reflection from complex line-of-sight absorption in the nearby Seyfert NGC 4151, using a suite of Suzaku, NuSTAR, and XMM-Newton observations. Extending upon earlier published work, we pursue a physically motivated model using the latest angle-resolved version of the lamp-post geometry reflection model relxillCp_lp together with a Comptonization continuum. We use the long-look simultaneous Suzaku/NuSTAR observation to develop a baseline model wherein we model reflected emission as a combination of lamp-post components at the heights of 1.2 and 15.0 gravitational radii. We argue for a vertically extended corona as opposed to two compact and distinct primary sources. We find two neutral absorbers (one full-covering and one partial-covering), an ionized absorber (log ξ = 2.8), and a highly-ionized ultra-fast outflow, which have all been reported previously. All analyzed spectra are well described by this baseline model. The bulk of the spectral variability between 1 keV and 6 keV can be accounted for by changes in the column density of both neutral absorbers, which appear to be degenerate and inversely correlated with the variable hard continuum component flux. We track variability in absorption on both short (2 d) and long ( 1 yr) timescales; the observed evolution is either consistent with changes in the absorber structure (clumpy absorber at distances ranging from the broad line region to the inner torus or a dusty radiatively driven wind) or a geometrically stable neutral absorber that becomes increasingly ionized at a rising flux level. The soft X-rays below 1 keV are dominated by photoionized emission from extended gas that may act as a warm mirror for the nuclear radiation.
Self-consistent Black Hole Accretion Spectral Models and the Forgotten Role of Coronal Comptonization of Reflection EmissionSteiner, James F.García, Javier A.Eikmann, WiebkeMcClintock, Jeffrey E.Brenneman, Laura W.Dauser, ThomasFabian, Andrew C.DOI: info:10.3847/1538-4357/836/1/119v. 836119
Steiner, James F., García, Javier A., Eikmann, Wiebke, McClintock, Jeffrey E., Brenneman, Laura W., Dauser, Thomas, and Fabian, Andrew C. 2017. "Self-consistent Black Hole Accretion Spectral Models and the Forgotten Role of Coronal Comptonization of Reflection Emission." The Astrophysical Journal 836:119. https://doi.org/10.3847/1538-4357/836/1/119
ID: 142796
Type: article
Authors: Steiner, James F.; García, Javier A.; Eikmann, Wiebke; McClintock, Jeffrey E.; Brenneman, Laura W.; Dauser, Thomas; Fabian, Andrew C.
Abstract: Continuum and reflection spectral models have each been widely employed in measuring the spins of accreting black holes. However, the two approaches have not been implemented together in a photon-conserving, self-consistent framework. We develop such a framework using the black hole X-ray binary GX 339-4 as a touchstone source, and we demonstrate three important ramifications. (1) Compton scattering of reflection emission in the corona is routinely ignored, but is an essential consideration given that reflection is linked to the regimes with strongest Comptonization. Properly accounting for this causes the inferred reflection fraction to increase substantially, especially for the hard state. Another important impact of the Comptonization of reflection emission by the corona is the downscattered tail. Downscattering has the potential to mimic the relativistically broadened red wing of the Fe line associated with a spinning black hole. (2) Recent evidence for a reflection component with a harder spectral index than the power-law continuum is naturally explained as Compton-scattered reflection emission. (3) Photon conservation provides an important constraint on the hard state's accretion rate. For bright hard states, we show that disk truncation to large scales R\gg {R}{ISCO} is unlikely as this would require accretion rates far in excess of the observed \dot{M} of the brightest soft states. Our principal conclusion is that when modeling relativistically broadened reflection, spectral models should allow for coronal Compton scattering of the reflection features, and when possible, take advantage of the additional constraining power from linking to the thermal disk component.
The quiescent intracluster medium in the core of the Perseus clusterHitomi CollaborationAharonian, FelixAkamatsu, HirokiAkimoto, FumieAllen, Steven W.Anabuki, NaohisaAngelini, LorellaArnaud, KeithAudard, MarcAwaki, HisamitsuAxelsson, MagnusBamba, AyaBautz, MarshallBlandford, RogerBrenneman, LauraBrown, Gregory V.Bulbul, EsraCackett, EdwardChernyakova, MariaChiao, MengCoppi, PaoloCostantini, Elisade Plaa, Jelleden Herder, Jan-WillemDone, ChrisDotani, TadayasuEbisawa, KenEckart, MeganEnoto, TeruakiEzoe, YuichiroFabian, Andrew C.Ferrigno, CarloFoster, AdamFujimoto, RyuichiFukazawa, YasushiFuruzawa, AkihiroGaleazzi, MassimilianoGallo, LuigiGandhi, PoshakGiustini, MargheritaGoldwurm, AndreaGu, LiyiGuainazzi, MatteoHaba, YoshitoHagino, KouichiHamaguchi, KenjiHarrus, IlanaHatsukade, IsamuHayashi, KatsuhiroHayashi, TakayukiHayashida, KiyoshiHiraga, JunkoHornschemeier, AnnHoshino, AkioHughes, JohnIizuka, RyoInoue, HajimeInoue, YoshiyukiIshibashi, KazunoriIshida, ManabuIshikawa, KumiIshisaki, YoshitakaItoh, MasayukiIyomoto, NaokoKaastra, JelleKallman, TimothyKamae, TuneyoshiKara, ErinKataoka, JunKatsuda, SatoruKatsuta, JunichiroKawaharada, MadokaKawai, NobuyukiKelley, RichardKhangulyan, DmitryKilbourne, CarolineKing, AshleyKitaguchi, TakaoKitamoto, ShunjiKitayama, TetsuKohmura, TakayoshiKokubun, MotohideKoyama, ShuKoyama, KatsujiKretschmar, PeterKrimm, HansKubota, AyaKunieda, HideyoLaurent, PhilippeLebrun, FrançoisLee, Shiu-HangLeutenegger, MauriceLimousin, OlivierLoewenstein, MichaelLong, Knox S.Lumb, DavidMadejski, GrzegorzMaeda, YoshitomoMaier, DanielMakishima, KazuoMarkevitch, MaximMatsumoto, HironoriMatsushita, KyokoMcCammon, DanMcNamara, BrianMehdipour, MissaghMiller, EricMiller, JonMineshige, ShinMitsuda, KazuhisaMitsuishi, IkuyukiMiyazawa, TakuyaMizuno, TsunefumiMori, HideyukiMori, KojiMoseley, HarveyMukai, KojiMurakami, HiroshiMurakami, ToshioMushotzky, RichardNagino, RyoNakagawa, TakaoNakajima, HiroshiNakamori, TakeshiNakano, ToshioNakashima, ShinyaNakazawa, KazuhiroNobukawa, MasayoshiNoda, HirofumiNomachi, MasaharuO'Dell, SteveOdaka, HirokazuOhashi, TakayaOhno, MasanoriOkajima, TakashiOta, NaomiOzaki, MasanobuPaerels, FritsPaltani, StephaneParmar, ArvindPetre, RobertPinto, CiroPohl, MartinPorter, F. ScottPottschmidt, KatjaRamsey, BrianReynolds, ChristopherRussell, HelenSafi-Harb, SamarSaito, ShinyaSakai, KazuhiroSameshima, HiroakiSato, GoroSato, KosukeSato, RieSawada, MakotoSchartel, NorbertSerlemitsos, PeterSeta, HiromiShidatsu, MegumiSimionescu, AuroraSmith, RandallSoong, YangStawarz, LukaszSugawara, YasuharuSugita, SatoshiSzymkowiak, AndrewTajima, HiroyasuTakahashi, HiromitsuTakahashi, TadayukiTakeda, Shin'ichiroTakei, YohTamagawa, ToruTamura, KeisukeTamura, TakayukiTanaka, TakaakiTanaka, YasuoTanaka, YasuyukiTashiro, MakotoTawara, YuzuruTerada, YukikatsuTerashima, YuichiTombesi, FrancescoTomida, HiroshiTsuboi, YohkoTsujimoto, MasahiroTsunemi, HiroshiTsuru, TakeshiUchida, HiroyukiUchiyama, HidekiUchiyama, YasunobuUeda, ShutaroUeda, YoshihiroUeno, ShiroUno, Shin'ichiroUrry, MegUrsino, Eugeniode Vries, CorWatanabe, ShinWerner, NorbertWik, DanielWilkins, DanWilliams, BrianYamada, ShinyaYamaguchi, HiroyaYamaoka, KazutakaYamasaki, Noriko Y.Yamauchi, MakotoYamauchi, ShigeoYaqoob, TahirYatsu, YoichiYonetoku, DaisukeYoshida, AtsumasaYuasa, TakayukiZhuravleva, IrinaZoghbi, AbderahmenDOI: info:10.1038/nature18627v. 535117–121
Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Anabuki, Naohisa, Angelini, Lorella, Arnaud, Keith, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall, Blandford, Roger, Brenneman, Laura, Brown, Gregory V., Bulbul, Esra, Cackett, Edward, Chernyakova, Maria, Chiao, Meng, Coppi, Paolo, Costantini, Elisa, de Plaa, Jelle, den Herder, Jan-Willem, Done, Chris et al. 2016. "The quiescent intracluster medium in the core of the Perseus cluster." Nature 535:117– 121. https://doi.org/10.1038/nature18627
ID: 139976
Type: article
Authors: Hitomi Collaboration; Aharonian, Felix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steven W.; Anabuki, Naohisa; Angelini, Lorella; Arnaud, Keith; Audard, Marc; Awaki, Hisamitsu; Axelsson, Magnus; Bamba, Aya; Bautz, Marshall; Blandford, Roger; Brenneman, Laura; Brown, Gregory V.; Bulbul, Esra; Cackett, Edward; Chernyakova, Maria; Chiao, Meng; Coppi, Paolo; Costantini, Elisa; de Plaa, Jelle; den Herder, Jan-Willem; Done, Chris; Dotani, Tadayasu; Ebisawa, Ken; Eckart, Megan; Enoto, Teruaki; Ezoe, Yuichiro; Fabian, Andrew C.; Ferrigno, Carlo; Foster, Adam; Fujimoto, Ryuichi; Fukazawa, Yasushi; Furuzawa, Akihiro; Galeazzi, Massimiliano; Gallo, Luigi; Gandhi, Poshak; Giustini, Margherita; Goldwurm, Andrea; Gu, Liyi; Guainazzi, Matteo; Haba, Yoshito; Hagino, Kouichi; Hamaguchi, Kenji; Harrus, Ilana; Hatsukade, Isamu; Hayashi, Katsuhiro; Hayashi, Takayuki; Hayashida, Kiyoshi; Hiraga, Junko; Hornschemeier, Ann; Hoshino, Akio; Hughes, John; Iizuka, Ryo; Inoue, Hajime; Inoue, Yoshiyuki; Ishibashi, Kazunori; Ishida, Manabu; Ishikawa, Kumi; Ishisaki, Yoshitaka; Itoh, Masayuki; Iyomoto, Naoko; Kaastra, Jelle; Kallman, Timothy; Kamae, Tuneyoshi; Kara, Erin; Kataoka, Jun; Katsuda, Satoru; Katsuta, Junichiro; Kawaharada, Madoka; Kawai, Nobuyuki; Kelley, Richard; Khangulyan, Dmitry; Kilbourne, Caroline; King, Ashley; Kitaguchi, Takao; Kitamoto, Shunji; Kitayama, Tetsu; Kohmura, Takayoshi; Kokubun, Motohide; Koyama, Shu; Koyama, Katsuji; Kretschmar, Peter; Krimm, Hans; Kubota, Aya; Kunieda, Hideyo; Laurent, Philippe; Lebrun, François; Lee, Shiu-Hang; Leutenegger, Maurice; Limousin, Olivier; Loewenstein, Michael; Long, Knox S.; Lumb, David; Madejski, Grzegorz; Maeda, Yoshitomo; Maier, Daniel; Makishima, Kazuo; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian; Mehdipour, Missagh; Miller, Eric; Miller, Jon; Mineshige, Shin; Mitsuda, Kazuhisa; Mitsuishi, Ikuyuki; Miyazawa, Takuya; Mizuno, Tsunefumi; Mori, Hideyuki; Mori, Koji; Moseley, Harvey; Mukai, Koji; Murakami, Hiroshi; Murakami, Toshio; Mushotzky, Richard; Nagino, Ryo; Nakagawa, Takao; Nakajima, Hiroshi; Nakamori, Takeshi; Nakano, Toshio; Nakashima, Shinya; Nakazawa, Kazuhiro; Nobukawa, Masayoshi; Noda, Hirofumi; Nomachi, Masaharu; O'Dell, Steve; Odaka, Hirokazu; Ohashi, Takaya; Ohno, Masanori; Okajima, Takashi; Ota, Naomi; Ozaki, Masanobu; Paerels, Frits; Paltani, Stephane; Parmar, Arvind; Petre, Robert; Pinto, Ciro; Pohl, Martin; Porter, F. Scott; Pottschmidt, Katja; Ramsey, Brian; Reynolds, Christopher; Russell, Helen; Safi-Harb, Samar; Saito, Shinya; Sakai, Kazuhiro; Sameshima, Hiroaki; Sato, Goro; Sato, Kosuke; Sato, Rie; Sawada, Makoto; Schartel, Norbert; Serlemitsos, Peter; Seta, Hiromi; Shidatsu, Megumi; Simionescu, Aurora; Smith, Randall; Soong, Yang; Stawarz, Lukasz; Sugawara, Yasuharu; Sugita, Satoshi; Szymkowiak, Andrew; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shin'ichiro; Takei, Yoh; Tamagawa, Toru; Tamura, Keisuke; Tamura, Takayuki; Tanaka, Takaaki; Tanaka, Yasuo; Tanaka, Yasuyuki; Tashiro, Makoto; Tawara, Yuzuru; Terada, Yukikatsu; Terashima, Yuichi; Tombesi, Francesco; Tomida, Hiroshi; Tsuboi, Yohko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi; Uchida, Hiroyuki; Uchiyama, Hideki; Uchiyama, Yasunobu; Ueda, Shutaro; Ueda, Yoshihiro; Ueno, Shiro; Uno, Shin'ichiro; Urry, Meg; Ursino, Eugenio; de Vries, Cor; Watanabe, Shin; Werner, Norbert; Wik, Daniel; Wilkins, Dan; Williams, Brian; Yamada, Shinya; Yamaguchi, Hiroya; Yamaoka, Kazutaka; Yamasaki, Noriko Y.; Yamauchi, Makoto; Yamauchi, Shigeo; Yaqoob, Tahir; Yatsu, Yoichi; Yonetoku, Daisuke; Yoshida, Atsumasa; Yuasa, Takayuki; Zhuravleva, Irina; Zoghbi, Abderahmen
Abstract: Clusters of galaxies are the most massive gravitationally bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and many astrophysical processes. However, knowledge of the dynamics of the pervasive hot gas, the mass of which is much larger than the combined mass of all the stars in the cluster, is lacking. Such knowledge would enable insights into the injection of mechanical energy by the central supermassive black hole and the use of hydrostatic equilibrium for determining cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50-million-kelvin diffuse hot plasma filling its gravitational potential well. The active galactic nucleus of the central galaxy NGC 1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These bubbles probably induce motions in the intracluster medium and heat the inner gas, preventing runaway radiative cooling-a process known as active galactic nucleus feedback. Here we report X-ray observations of the core of the Perseus cluster, which reveal a remarkably quiescent atmosphere in which the gas has a line-of-sight velocity dispersion of 164 ± 10 kilometres per second in the region 30–60 kiloparsecs from the central nucleus. A gradient in the line-of-sight velocity of 150 ± 70 kilometres per second is found across the 60-kiloparsec image of the cluster core. Turbulent pressure support in the gas is four per cent of the thermodynamic pressure, with large-scale shear at most doubling this estimate. We infer that a total cluster mass determined from hydrostatic equilibrium in a central region would require little correction for turbulent pressure.
NuSTAR and Suzaku X-Ray Spectroscopy of NGC 4151: Evidence for Reflection from the Inner Accretion DiskKeck, M. L.Brenneman, L. W.Ballantyne, D. R.Bauer, F.Boggs, S. E.Christensen, F. E.Craig, W. W.Dauser, T.Elvis, M.Fabian, A. C.Fuerst, F.García, J.Grefenstette, B. W.Hailey, C. J.Harrison, F. A.Madejski, G.Marinucci, A.Matt, G.Reynolds, C. S.Stern, D.Walton, D. J.Zoghbi, A.DOI: info:10.1088/0004-637X/806/2/149v. 806149
Keck, M. L., Brenneman, L. W., Ballantyne, D. R., Bauer, F., Boggs, S. E., Christensen, F. E., Craig, W. W., Dauser, T., Elvis, M., Fabian, A. C., Fuerst, F., García, J., Grefenstette, B. W., Hailey, C. J., Harrison, F. A., Madejski, G., Marinucci, A., Matt, G., Reynolds, C. S., Stern, D., Walton, D. J., and Zoghbi, A. 2015. "NuSTAR and Suzaku X-Ray Spectroscopy of NGC 4151: Evidence for Reflection from the Inner Accretion Disk." The Astrophysical Journal 806:149. https://doi.org/10.1088/0004-637X/806/2/149
ID: 136568
Type: article
Authors: Keck, M. L.; Brenneman, L. W.; Ballantyne, D. R.; Bauer, F.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Dauser, T.; Elvis, M.; Fabian, A. C.; Fuerst, F.; García, J.; Grefenstette, B. W.; Hailey, C. J.; Harrison, F. A.; Madejski, G.; Marinucci, A.; Matt, G.; Reynolds, C. S.; Stern, D.; Walton, D. J.; Zoghbi, A.
Abstract: We present X-ray timing and spectral analyses of simultaneous 150 ks Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku X-ray observations of the Seyfert 1.5 galaxy NGC 4151. We disentangle the continuum emission, absorption, and reflection properties of the active galactic nucleus (AGN) by applying inner accretion disk reflection and absorption-dominated models. With a time-averaged spectral analysis, we find strong evidence for relativistic reflection from the inner accretion disk. We find that relativistic emission arises from a highly ionized inner accretion disk with a steep emissivity profile, which suggests an intense, compact illuminating source. We find a preliminary, near-maximal black hole spin a\gt 0.9 accounting for statistical and systematic modeling errors. We find a relatively moderate reflection fraction with respect to predictions for the lamp post geometry, in which the illuminating corona is modeled as a point source. Through a time-resolved spectral analysis, we find that modest coronal and inner disk reflection (IDR) flux variation drives the spectral variability during the observations. We discuss various physical scenarios for the IDR model and we find that a compact corona is consistent with the observed features.
3C 273 with NuSTAR: Unveiling the Active Galactic NucleusMadsen, Kristin K.Fürst, FelixWalton, Dominic J.Harrison, Fiona A.Nalewajko, KrzysztofBallantyne, David R.Boggs, Steve E.Brenneman, Laura W.Christensen, Finn E.Craig, William W.Fabian, Andrew C.Forster, KarlGrefenstette, Brian W.Guainazzi, MatteoHailey, Charles J.Madejski, Greg M.Matt, GiorgioStern, DanielWalter, RolandZhang, William W.DOI: info:10.1088/0004-637X/812/1/14v. 81214
Madsen, Kristin K., Fürst, Felix, Walton, Dominic J., Harrison, Fiona A., Nalewajko, Krzysztof, Ballantyne, David R., Boggs, Steve E., Brenneman, Laura W., Christensen, Finn E., Craig, William W., Fabian, Andrew C., Forster, Karl, Grefenstette, Brian W., Guainazzi, Matteo, Hailey, Charles J., Madejski, Greg M., Matt, Giorgio, Stern, Daniel, Walter, Roland, and Zhang, William W. 2015. "3C 273 with NuSTAR: Unveiling the Active Galactic Nucleus." The Astrophysical Journal 812:14. https://doi.org/10.1088/0004-637X/812/1/14
ID: 140585
Type: article
Authors: Madsen, Kristin K.; Fürst, Felix; Walton, Dominic J.; Harrison, Fiona A.; Nalewajko, Krzysztof; Ballantyne, David R.; Boggs, Steve E.; Brenneman, Laura W.; Christensen, Finn E.; Craig, William W.; Fabian, Andrew C.; Forster, Karl; Grefenstette, Brian W.; Guainazzi, Matteo; Hailey, Charles J.; Madejski, Greg M.; Matt, Giorgio; Stern, Daniel; Walter, Roland; Zhang, William W.
Abstract: We present results from a 244 ks NuSTAR observation of 3C 273 obtained during a cross-calibration campaign with the Chandra, INTEGRAL, Suzaku, Swift, and XMM-Newton observatories. We show that the spectrum, when fit with a power-law model using data from all observatories except INTEGRAL over the 1-78 keV band, leaves significant residuals in the NuSTAR data between 30 and 78 keV. The NuSTAR 3-78 keV spectrum is well described by an exponentially cutoff power law ({{G }}=1.646+/- 0.006, {E}{cutoff}={202}-34+51 keV) with a weak reflection component from cold, dense material. There is also evidence for a weak ({EW}=23+/- 11 eV) neutral iron line. We interpret these features as arising from coronal emission plus reflection off an accretion disk or distant material. Beyond 80 keV INTEGRAL data show clear excess flux relative to an extrapolation of the active galactic nucleus model fit to NuSTAR. This high-energy power law is consistent with the presence of a beamed jet, which begins to dominate over emission from the inner accretion flow at 30-40 keV. Modeling the jet locally (in the NuSTAR + INTEGRAL band) as a power law, we find that the coronal component is fit by {{{G }}}{AGN}=1.638+/- 0.045, {E}{cutoff}=47+/- 15 {keV}, and jet photon index by {{{G }}}{jet}=1.05+/- 0.4. We also consider Fermi/LAT observations of 3C 273, and here the broadband spectrum of the jet can be described by a log-parabolic model, peaking at ˜2 MeV. Finally, we investigate the spectral variability in the NuSTAR band and find an inverse correlation between flux and G.
Revealing the X-ray variability of AGN with principal component analysisParker, M. L.Fabian, A. C.Matt, G.Koljonen, K. I. I.Kara, E.Alston, W.Walton, D. J.Marinucci, A.Brenneman, L.Risaliti, G.DOI: info:10.1093/mnras/stu2424v. 44772–96
Parker, M. L., Fabian, A. C., Matt, G., Koljonen, K. I. I., Kara, E., Alston, W., Walton, D. J., Marinucci, A., Brenneman, L., and Risaliti, G. 2015. "Revealing the X-ray variability of AGN with principal component analysis." Monthly Notices of the Royal Astronomical Society 447:72– 96. https://doi.org/10.1093/mnras/stu2424
ID: 135165
Type: article
Authors: Parker, M. L.; Fabian, A. C.; Matt, G.; Koljonen, K. I. I.; Kara, E.; Alston, W.; Walton, D. J.; Marinucci, A.; Brenneman, L.; Risaliti, G.
Abstract: We analyse a sample of 26 active galactic nuclei (AGN) with deep XMM-Newton observations, using principal component analysis (PCA) to find model-independent spectra of the different variable components. In total, we identify at least 12 qualitatively different patterns of spectral variability, involving several different mechanisms, including five sources which show evidence of variable relativistic reflection (MCG-6-30-15, NGC 4051, 1H 0707-495, NGC 3516 and Mrk 766) and three which show evidence of varying partial covering neutral absorption (NGC 4395, NGC 1365 and NGC 4151). In over half of the sources studied, the variability is dominated by changes in a power-law continuum, both in terms of changes in flux and power-law index, which could be produced by propagating fluctuations within the corona. Simulations are used to find unique predictions for different physical models, and we then attempt to qualitatively match the results from the simulations to the behaviour observed in the real data. We are able to explain a large proportion of the variability in these sources using simple models of spectral variability, but more complex models may be needed for the remainder. We have begun the process of building up a library of different principal components, so that spectral variability in AGN can quickly be matched to physical processes. We show that PCA can be an extremely powerful tool for distinguishing different patterns of variability in AGN, and that it can be used effectively on the large amounts of high-quality archival data available from the current generation of X-ray telescopes. We will make our PCA code available upon request to the lead author.
The Multi-layer Variable Absorbers in NGC 1365 Revealed by XMM-Newton and NuSTARRivers, E.Risaliti, G.Walton, D. J.Harrison, F.Arévalo, P.Baur, F. E.Boggs, S. E.Brenneman, L. W.Brightman, M.Christensen, F. E.Craig, W. W.Fürst, F.Hailey, C. J.Hickox, R. C.Marinucci, A.Reeves, J.Stern, D.Zhang, W. W.DOI: info:10.1088/0004-637X/804/2/107v. 804107
Rivers, E., Risaliti, G., Walton, D. J., Harrison, F., Arévalo, P., Baur, F. E., Boggs, S. E., Brenneman, L. W., Brightman, M., Christensen, F. E., Craig, W. W., Fürst, F., Hailey, C. J., Hickox, R. C., Marinucci, A., Reeves, J., Stern, D., and Zhang, W. W. 2015. "The Multi-layer Variable Absorbers in NGC 1365 Revealed by XMM-Newton and NuSTAR." The Astrophysical Journal 804:107. https://doi.org/10.1088/0004-637X/804/2/107
ID: 136420
Type: article
Authors: Rivers, E.; Risaliti, G.; Walton, D. J.; Harrison, F.; Arévalo, P.; Baur, F. E.; Boggs, S. E.; Brenneman, L. W.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Fürst, F.; Hailey, C. J.; Hickox, R. C.; Marinucci, A.; Reeves, J.; Stern, D.; Zhang, W. W.
Abstract: Between 2012 July and 2013 February, NuSTAR and XMM-Newton performed four long-look joint observations of the type 1.8 Seyfert, NGC 1365. We have analyzed the variable absorption seen in these observations in order to characterize the geometry of the absorbing material. Two of the observations caught NGC 1365 in an unusually low absorption state, revealing complexity in the multi-layer absorber that had previously been hidden. We find the need for three distinct zones of neutral absorption in addition to the two zones of ionized absorption and the Compton-thick torus previously seen in this source. The most prominent absorber is likely associated with broad-line region clouds with column densities of around ~1023 cm-2 and a highly clumpy nature as evidenced by an occultation event in 2013 February. We also find evidence of a patchy absorber with a variable column around ~1022 cm-2 and a line-of-sight covering fraction of 0.3–0.9, which responds directly to the intrinsic source flux, possibly due to a wind geometry. A full-covering, constant absorber with a low column density of ~1 × 1022 cm-2 is also present, though the location of this low density haze is unknown.
NuSTAR Reveals the Comptonizing Corona of the Broad-line Radio Galaxy 3C 382Ballantyne, D. R.Bollenbacher, J. M.Brenneman, L. W.Madsen, K. K.Baloković, MislavBoggs, S. E.Christensen, F. E.Craig, W. W.Gandhi, P.Hailey, C. J.Harrison, F. A.Lohfink, A. M.Marinucci, A.Markwardt, C. B.Stern, D.Walton, D. J.Zhang, W. W.DOI: info:10.1088/0004-637X/794/1/62v. 79462
Ballantyne, D. R., Bollenbacher, J. M., Brenneman, L. W., Madsen, K. K., Baloković, Mislav, Boggs, S. E., Christensen, F. E., Craig, W. W., Gandhi, P., Hailey, C. J., Harrison, F. A., Lohfink, A. M., Marinucci, A., Markwardt, C. B., Stern, D., Walton, D. J., and Zhang, W. W. 2014. "NuSTAR Reveals the Comptonizing Corona of the Broad-line Radio Galaxy 3C 382." The Astrophysical Journal 794:62. https://doi.org/10.1088/0004-637X/794/1/62
ID: 131108
Type: article
Authors: Ballantyne, D. R.; Bollenbacher, J. M.; Brenneman, L. W.; Madsen, K. K.; Baloković, Mislav; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Gandhi, P.; Hailey, C. J.; Harrison, F. A.; Lohfink, A. M.; Marinucci, A.; Markwardt, C. B.; Stern, D.; Walton, D. J.; Zhang, W. W.
Abstract: Broad-line radio galaxies (BLRGs) are active galactic nuclei that produce powerful, large-scale radio jets, but appear as Seyfert 1 galaxies in their optical spectra. In the X-ray band, BLRGs also appear like Seyfert galaxies, but with flatter spectra and weaker reflection features. One explanation for these properties is that the X-ray continuum is diluted by emission from the jet. Here, we present two NuSTAR observations of the BLRG 3C 382 that show clear evidence that the continuum of this source is dominated by thermal Comptonization, as in Seyfert 1 galaxies. The two observations were separated by over a year and found 3C 382 in different states separated by a factor of 1.7 in flux. The lower flux spectrum has a photon-index of \Gamma =1.68^{+0.03}_{-0.02}, while the photon-index of the higher flux spectrum is \Gamma =1.78^{+0.02}_{-0.03}. Thermal and anisotropic Comptonization models provide an excellent fit to both spectra and show that the coronal plasma cooled from kTe = 330 ± 30 keV in the low flux data to 231^{+50}_{-88} keV in the high flux observation. This cooling behavior is typical of Comptonizing corona in Seyfert galaxies and is distinct from the variations observed in jet-dominated sources. In the high flux observation, simultaneous Swift data are leveraged to obtain a broadband spectral energy distribution and indicates that the corona intercepts ~10% of the optical and ultraviolet emitting accretion disk. 3C 382 exhibits very weak reflection features, with no detectable relativistic Fe Kα line, that may be best explained by an outflowing corona combined with an ionized inner accretion disk.
The Broad-band X-Ray Spectrum of IC 4329A from a Joint NuSTAR/Suzaku ObservationBrenneman, L. W.Madejski, G.Fuerst, F.Matt, G.Elvis, M.Harrison, F. A.Ballantyne, D. R.Boggs, S. E.Christensen, F. E.Craig, W. W.Fabian, A. C.Grefenstette, B. W.Hailey, C. J.Madsen, K. K.Marinucci, A.Rivers, E.Stern, D.Walton, D. J.Zhang, W. W.DOI: info:10.1088/0004-637X/788/1/61v. 78861
Brenneman, L. W., Madejski, G., Fuerst, F., Matt, G., Elvis, M., Harrison, F. A., Ballantyne, D. R., Boggs, S. E., Christensen, F. E., Craig, W. W., Fabian, A. C., Grefenstette, B. W., Hailey, C. J., Madsen, K. K., Marinucci, A., Rivers, E., Stern, D., Walton, D. J., and Zhang, W. W. 2014. "The Broad-band X-Ray Spectrum of IC 4329A from a Joint NuSTAR/Suzaku Observation." The Astrophysical Journal 788:61. https://doi.org/10.1088/0004-637X/788/1/61
ID: 127255
Type: article
Authors: Brenneman, L. W.; Madejski, G.; Fuerst, F.; Matt, G.; Elvis, M.; Harrison, F. A.; Ballantyne, D. R.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Fabian, A. C.; Grefenstette, B. W.; Hailey, C. J.; Madsen, K. K.; Marinucci, A.; Rivers, E.; Stern, D.; Walton, D. J.; Zhang, W. W.
Abstract: We have obtained a deep, simultaneous observation of the bright, nearby Seyfert galaxy IC 4329A with Suzaku and NuSTAR. Through a detailed spectral analysis, we are able to robustly separate the continuum, absorption, and distant reflection components in the spectrum. The absorbing column is found to be modest ({\sim }6 \times 10^{21} {\, cm^{-2}\,}), and does not introduce any significant curvature in the Fe K band. We are able to place a strong constraint on the presence of a broadened Fe Kα line (E_rest=6.46^{+0.08}_{-0.07} \, keV with \sigma =0.33^{+0.08}_{-0.07} \, keV and EW=34^{+8}_{-7} \, eV), though we are not able to constrain any of the parameters of a relativistic reflection model. These results highlight the range in broad Fe K line strengths observed in nearby, bright, active galactic nuclei (roughly an order of magnitude), and imply a corresponding range in the physical properties of the inner accretion disk in these sources. We have also updated our previously reported measurement of the high-energy cutoff of the hard X-ray emission using both observatories rather than just NuSTAR alone: E cut = 186 ± 14 keV. This high-energy cutoff acts as a proxy for the temperature of the coronal electron plasma, enabling us to further separate this parameter from the plasma's optical depth and to update our results for these parameters as well. We derive kT=50^{+6}_{-3} \, keV with \tau =2.34^{+0.16}_{-0.11} using a spherical geometry, kT = 61 ± 1 keV with τ = 0.68 ± 0.02 for a slab geometry, with both having an equivalent goodness-of-fit.
Measuring the Coronal Properties of IC 4329A with NuSTARBrenneman, L. W.Madejski, G.Fuerst, F.Matt, G.Elvis, M.Harrison, F. A.Ballantyne, D. R.Boggs, S. E.Christensen, F. E.Craig, W. W.Fabian, A. C.Grefenstette, B. W.Hailey, C. J.Madsen, K. K.Marinucci, A.Rivers, E.Stern, D.Walton, D. J.Zhang, W. W.DOI: info:10.1088/0004-637X/781/2/83v. 78183
Brenneman, L. W., Madejski, G., Fuerst, F., Matt, G., Elvis, M., Harrison, F. A., Ballantyne, D. R., Boggs, S. E., Christensen, F. E., Craig, W. W., Fabian, A. C., Grefenstette, B. W., Hailey, C. J., Madsen, K. K., Marinucci, A., Rivers, E., Stern, D., Walton, D. J., and Zhang, W. W. 2014. "Measuring the Coronal Properties of IC 4329A with NuSTAR." The Astrophysical Journal 781:83. https://doi.org/10.1088/0004-637X/781/2/83
ID: 119051
Type: article
Authors: Brenneman, L. W.; Madejski, G.; Fuerst, F.; Matt, G.; Elvis, M.; Harrison, F. A.; Ballantyne, D. R.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Fabian, A. C.; Grefenstette, B. W.; Hailey, C. J.; Madsen, K. K.; Marinucci, A.; Rivers, E.; Stern, D.; Walton, D. J.; Zhang, W. W.
Abstract: We present an analysis of a ~160 ks NuSTAR observation of the nearby bright Seyfert galaxy IC 4329A. The high-quality broadband spectrum enables us to separate the effects of distant reflection from the direct coronal continuum, and to therefore accurately measure the high-energy cutoff to be E_cut=178^{+74}_{-40}\, keV. The coronal emission arises from accretion disk photons Compton up-scattered by a thermal plasma, with the spectral index and cutoff being due to a combination of the finite plasma temperature and optical depth. Applying standard Comptonization models, we measure both physical properties independently using the best signal to noise obtained to date in an active galactic nucleus over the 3-79 keV band. We derive kT_e=37^{+7}_{-6}\, keV with \tau =1.25^{+0.20}_{-0.10} assuming a slab geometry for the plasma, and kT_e=33^{+6}_{-6}\, keV with \tau =3.41^{+0.58}_{-0.38} for a spherical geometry, with both having an equivalent goodness-of-fit.
Improved Reflection Models of Black Hole Accretion Disks: Treating the Angular Distribution of X- RaysGarcía, J.Dauser, T.Lohfink, A.Kallman, T. R.Steiner, J. F.McClintock, J. E.Brenneman, L.Wilms, J.Eikmann, W.Reynolds, C. S.Tombesi, F.DOI: info:10.1088/0004-637X/782/2/76v. 78276
García, J., Dauser, T., Lohfink, A., Kallman, T. R., Steiner, J. F., McClintock, J. E., Brenneman, L., Wilms, J., Eikmann, W., Reynolds, C. S., and Tombesi, F. 2014. "Improved Reflection Models of Black Hole Accretion Disks: Treating the Angular Distribution of X- Rays." The Astrophysical Journal 782:76. https://doi.org/10.1088/0004-637X/782/2/76
ID: 119060
Type: article
Authors: García, J.; Dauser, T.; Lohfink, A.; Kallman, T. R.; Steiner, J. F.; McClintock, J. E.; Brenneman, L.; Wilms, J.; Eikmann, W.; Reynolds, C. S.; Tombesi, F.
Abstract: X-ray reflection models are used to constrain the properties of the accretion disk, such as the degree of ionization of the gas and the elemental abundances. In combination with general relativistic ray tracing codes, additional parameters like the spin of the black hole and the inclination to the system can be determined. However, current reflection models used for such studies only provide angle-averaged solutions for the flux reflected at the surface of the disk. Moreover, the emission angle of the photons changes over the disk due to relativistic light bending. To overcome this simplification, we have constructed an angle-dependent reflection model with the XILLVER code and self-consistently connected it with the relativistic blurring code RELLINE. The new model, relxill, calculates the proper emission angle of the radiation at each point on the accretion disk and then takes the corresponding reflection spectrum into account. We show that the reflected spectra from illuminated disks follow a limb-brightening law highly dependent on the ionization of disk and yet different from the commonly assumed form Ivpropln (1 + 1/μ). A detailed comparison with the angle-averaged model is carried out in order to determine the bias in the parameters obtained by fitting a typical relativistic reflection spectrum. These simulations reveal that although the spin and inclination are mildly affected, the Fe abundance can be overestimated by up to a factor of two when derived from angle-averaged models. The fit of the new model to the Suzaku observation of the Seyfert galaxy Ark 120 clearly shows a significant improvement in the constraint of the physical parameters, in particular by enhancing the accuracy in the inclination angle and the spin determinations.