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X-ray absorption and reflection in active galactic nuclei

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The Astronomy and Astrophysics Review Aims and scope

Abstract

X-ray spectroscopy offers an opportunity to study the complex mixture of emitting and absorbing components in the circumnuclear regions of active galactic nuclei (AGN), and to learn about the accretion process that fuels AGN and the feedback of material to their host galaxies. We describe the spectral signatures that may be studied and review the X-ray spectra and spectral variability of active galaxies, concentrating on progress from recent Chandra, XMM-Newton and Suzaku data for local type 1 AGN. We describe the evidence for absorption covering a wide range of column densities, ionization and dynamics, and discuss the growing evidence for partial-covering absorption from data at energies ≳ 10 keV. Such absorption can also explain the observed X-ray spectral curvature and variability in AGN at lower energies and is likely an important factor in shaping the observed properties of this class of source. Consideration of self-consistent models for local AGN indicates that X-ray spectra likely comprise a combination of absorption and reflection effects from material originating within a few light days of the black hole as well as on larger scales. It is likely that AGN X-ray spectra may be strongly affected by the presence of disk-wind outflows that are expected in systems with high accretion rates, and we describe models that attempt to predict the effects of radiative transfer through such winds, and discuss the prospects for new data to test and address these ideas.

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References

  • Abramowicz MA, Czerny B, Lasota JP, Szuszkiewicz E (1988) Slim accretion disks. Astrophys J 332: 646–658. doi:10.1086/166683

    ADS  Google Scholar 

  • Abramowicz MA, Chen X, Kato S, Lasota JP, Regev O (1995) Thermal equilibria of accretion disks. Astrophys J Lett 438: L37–L39. doi:10.1086/187709 arXiv:astro-ph/9409018

    ADS  Google Scholar 

  • Abrassart A, Czerny B (2000) Toy model of obscurational variability in active galactic nuclei. Astron Astrophys 356: 475–489 arXiv:astro-ph/0001515

    ADS  Google Scholar 

  • Antonucci R (1993) Unified models for active galactic nuclei and quasars. Ann Rev Astron Astrophys 31: 473–521. doi:10.1146/annurev.aa.31.090193.002353

    ADS  Google Scholar 

  • Arnaud KA (1996) XSPEC: the first ten years. In: Jacoby GH, Barnes J (eds) Astronomical data analysis software and systems V. In: Astronomical Society of the Pacific Conference Series, vol 101, pp 17–20

  • Arnaud KA, Branduardi-Raymont G, Culhane JL, Fabian AC, Hazard C, McGlynn TA, Shafer RA, Tennant AF, Ward MJ (1985) EXOSAT observations of a strong soft X-ray excess in MKN 841. Monthly Not RAS 217: 105–113

    ADS  Google Scholar 

  • Axon DJ, Pedlar A, Unger SW, Meurs EJA, Whittle DM (1989) The jets of 3C120. Nature 341: 631–633. doi:10.1038/341631a0

    ADS  Google Scholar 

  • Ballantyne DR, Vaughan S, Fabian AC (2003) A two-component ionized reflection model of MCG-6-30-15. Mon Not RAS 342: 239–248. doi:10.1046/j.1365-8711.2003.06533.x arXiv:astro-ph/0302288

    ADS  Google Scholar 

  • Bassani L, Dadina M, Maiolino R, Salvati M, Risaliti G, della Ceca R, Matt G, Zamorani G (1999) A three-dimensional diagnostic diagram for Seyfert 2 galaxies: probing X-Ray absorption and compton thickness. Astrophys J Suppl 121: 473–482. doi:10.1086/313202 arXiv:astro-ph/9811074

    ADS  Google Scholar 

  • Bautista MA, Kallman TR (2000) Recombination spectra of Helium-like ions. Astrophys J 544: 581–591. doi:10.1086/317206 arXiv:astro-ph/0006371

    ADS  Google Scholar 

  • Beckmann V, Barthelmy SD, Courvoisier TJL, Gehrels N, Soldi S, Tueller J, Wendt G (2007) Hard X-ray variability of active galactic nuclei. Astron Astrophys 475: 827–835. doi:10.1051/0004-6361:20078355

    ADS  Google Scholar 

  • Behar E, Rasmussen AP, Blustin AJ, Sako M, Kahn SM, Kaastra JS, Branduardi-Raymont G, Steenbrugge KC (2003) A long look at NGC 3783 with the XMM-Newton reflection grating spectrometer. Astrophys J 598: 232–241. doi:10.1086/378853 arXiv:astro-ph/0307467

    ADS  Google Scholar 

  • Bian W, Zhao Y (2003) On X-ray variability in narrow-line and broad-line active galactic nuclei. Mon Not RAS 343: 164–168. doi:10.1046/j.1365-8711.2003.06650.x arXiv:astro-ph/0303546

    ADS  Google Scholar 

  • Bianchi S, Matt G (2002) Ionized iron Kalpha lines in AGN X-ray spectra. Astron Astrophys 387: 76–81. doi:10.1051/0004-6361:20020372 arXiv:astro-ph/0203178

    ADS  Google Scholar 

  • Bianchi S, Matt G, Balestra I, Perola GC (2003) The origin of the iron lines in NGC 7213. Astron Astrophys 407: L21–L24. doi:10.1051/0004-6361:20031054 arXiv:astro-ph/0307143

    ADS  Google Scholar 

  • Bianchi S, Matt G, Balestra I, Guainazzi M, Perola GC (2004) X-ray reprocessing in Seyfert galaxies: simultaneous XMM-Newton/BeppoSAX observations. Astron Astrophys 422: 65–76. doi:10.1051/0004-6361:20047128 arXiv:astro-ph/0404308

    ADS  Google Scholar 

  • Bianchi S, Matt G, Nicastro F, Porquet D, Dubau J (2005) FeXXV and FeXXVI lines from low-velocity, photoionized gas in the X-ray spectra of active galactic nuclei. Mon Not RAS 357: 599–607. doi:10.1111/j.1365-2966.2005.08661.x arXiv:astro-ph/0411603

    ADS  Google Scholar 

  • Bianchi S, La Franca F, Matt G, Guainazzi M, Jimenez Bailón E, Longinotti AL, Nicastro F, Pentericci L (2008) A broad-line region origin for the iron Kα line in NGC 7213. Mon Not RAS 389: L52–L56. doi:10.1111/j.1745-3933.2008.00521.x 0806.3876

    ADS  Google Scholar 

  • Blustin AJ, Page MJ, Fuerst SV, Branduardi-Raymont G, Ashton CE (2005) The nature and origin of Seyfert warm absorbers. Astron Astrophys 431: 111–125. doi:10.1051/0004-6361:20041775 arXiv:astro-ph/0411297

    ADS  Google Scholar 

  • Blustin AJ, Kriss GA, Holczer T, Behar E, Kaastra JS, Page MJ, Kaspi S, Branduardi-Raymont G, Steenbrugge KC (2007) The mass-energy budget of the ionised outflow in NGC 7469. Astron Astrophys 466: 107–118. doi:10.1051/0004-6361:20066883 arXiv:astro-ph/0702311

    ADS  Google Scholar 

  • Boller T, Brandt WN, Fink H (1996) Soft X-ray properties of narrow-line Seyfert 1 galaxies. Astron Astrophys 305: 53–73 arXiv:astro-ph/9504093

    ADS  Google Scholar 

  • Boller T, Brandt WN, Fabian AC, Fink HH (1997) ROSAT monitoring of persistent giant and rapid variability in the narrow-line Seyfert 1 galaxy IRAS 13224-3809. Mon Not RAS 289: 393–405 arXiv:astro-ph/9703114

    ADS  Google Scholar 

  • Bowyer CS, Lampton M, Mack J, de Mendonca F (1970) Detection of X-ray emission from 3c 273 and NGC 5128. Astrophys J Lett 161: L1

    ADS  Google Scholar 

  • Boyle BJ, Shanks T, Croom SM, Smith RJ, Miller L, Loaring N, Heymans C (2000) The 2dF QSO Redshift Survey. I. The optical luminosity function of quasi-stellar objects. Mon Not RAS 317: 1014–1022 arXiv:astro-ph/0005368

    ADS  Google Scholar 

  • Braito V, Reeves JN, Dewangan GC, George I, Griffiths RE, Markowitz A, Nandra K, Porquet D, Ptak A, Turner TJ, Yaqoob T, Weaver K (2007) Relativistic iron K emission and absorption in the seyfert 1.9 galaxy MCG-5-23-16. Astrophys J 670: 978–991. doi:10.1086/521916 0707.2950

    ADS  Google Scholar 

  • Brandt WN, Boller T, Fabian AC, Ruszkowski M (1999) ROSAT high-resolution imager monitoring of extreme X-ray variability in the narrow-line quasar PHL 1092. Mon Not RAS 303: L53–L57. doi:10.1046/j.1365-8711.1999.02411.x arXiv:astro-ph/9901353

    ADS  Google Scholar 

  • Branduardi-Raymont G, Sako M, Kahn SM, Brinkman AC, Kaastra JS, Page MJ (2001) Soft X-ray emission lines from a relativistic accretion disk in MCG-6-30-15 and Mrk 766. Astron Astrophys 365: L140–L145. doi:10.1051/0004-6361:20000209 arXiv:astro-ph/0011167

    ADS  Google Scholar 

  • Brenneman LW, Reynolds CS (2006) Constraining black hole spin via X-ray spectroscopy. Astrophys J 652: 1028–1043. doi:10.1086/508146 arXiv:astro-ph/0608502

    ADS  Google Scholar 

  • Burke BE, Mountain RW, Daniels PJ, Cooper MJ, Dolat VS (1993) CCD soft x-ray imagers for ASCA and AXAF. In: Siegmund OH (ed) Society of Photo-optical Instrumentation Engineers (SPIE) Conference Series. Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol 2006, pp 272–285

  • Camenzind M, Courvoisier TJL (1983) A wind and shock model for active galactic nuclei. Astrophys J 266: L83–L87. doi:10.1086/183983

    ADS  Google Scholar 

  • Ceballos MT, Barcons X (1996) Soft versus hard X-ray emission in active galactic nuclei: partial-covering and warm-plus-cold absorber models. Mon Not RAS 282: 493–500 arXiv:astro-ph/9604097

    ADS  Google Scholar 

  • Celotti A, Fabian AC, Rees MJ (1992) Dense thin clouds in the central regions of active galactic nuclei. Mon Not RAS 255: 419–422

    ADS  Google Scholar 

  • Chartas G, Brandt WN, Gallagher SC, Garmire GP (2002) CHANDRA detects relativistic broad absorption lines from APM 08279+5255. Astrophys J 579: 169–175. doi:10.1086/342744 arXiv:astro-ph/0207196

    ADS  Google Scholar 

  • Chartas G, Brandt WN, Gallagher SC (2003) XMM-Newton reveals the quasar outflow in PG 1115+080. Astrophys J 595: 85–93. doi:10.1086/377299 arXiv:astro-ph/0306125

    ADS  Google Scholar 

  • Chartas G, Eracleous M, Agol E, Gallagher SC (2004) Chandra observations of the cloverleaf quasar H1413+117: a unique laboratory for microlensing studies of a LoBAL quasar. Astrophys J 606: 78–84. doi:10.1086/382743 arXiv:astro-ph/0401240

    ADS  Google Scholar 

  • Chartas G, Kochanek CS, Dai X, Poindexter S, Garmire G (2008) X-ray microlensing in RXJ1131-1231 and HE1104-1805. ArXiv e-prints 0805.4492

  • Chelouche D, Netzer H (2005) Dynamical and spectral modeling of the ionized gas and nuclear environment in NGC 3783. Astrophys J 625: 95–107. doi:10.1086/429580 arXiv:astro-ph/0502272

    ADS  Google Scholar 

  • Chevallier L, Collin S, Dumont AM, Czerny B, Mouchet M, Gonçalves AC, Goosmann R (2006) The role of absorption and reflection in the soft X-ray excess of active galactic nuclei. I. Preliminary results. Astron Astrophys 449: 493–508. doi:10.1051/0004-6361:20053730 arXiv:astro-ph/0510700

    ADS  Google Scholar 

  • Collin S, Dumont AM, Godet O (2004) A new type of photoionized code required for the new era of X-ray spectroscopy. Astron Astrophys 419: 877–886. doi:10.1051/0004-6361:20041019 arXiv:astro-ph/0403009

    ADS  Google Scholar 

  • Crenshaw DM, Kraemer SB, George IM (2003) Mass loss from the nuclei of active galaxies. Ann Rev Astron Astrophys 41: 117–167. doi:10.1146/annurev.astro.41.082801.100328

    ADS  Google Scholar 

  • Crummy J, Fabian AC, Gallo L, Ross RR (2006) An explanation for the soft X-ray excess in active galactic nuclei. Mon Not RAS 365: 1067–1081. doi:10.1111/j.1365-2966.2005.09844.x arXiv:astro-ph/0511457

    Article  ADS  Google Scholar 

  • Czerny B, Elvis M (1987) Constraints on quasar accretion disks from the optical/ultraviolet/soft X-ray big bump. Astrophys J 321: 305–320. doi:10.1086/165630

    ADS  Google Scholar 

  • Czerny B, Nikołajuk M, Różańska A, Dumont AM, Loska Z, Zycki PT (2003) Universal spectral shape of high accretion rate AGN. Astron Astrophys 412: 317–329. doi:10.1051/0004-6361:20031441 arXiv:astro-ph/0309242

    ADS  Google Scholar 

  • Czerny B, Różańska A, Dovčiak M, Karas V, Dumont AM (2004) The structure and radiation spectra of illuminated accretion disks in AGN. II. Flare/spot model of X-ray variability. Astron Astrophys 420: 1–16. doi:10.1051/0004-6361:20035741 arXiv:astro-ph/0402394

    ADS  Google Scholar 

  • Dadina M (2008) Seyfert galaxies in the local Universe z < 1: the average X-ray spectrum as seen by BeppoSAX. Astron Astrophys 485: 417–424. doi:10.1051/0004-6361:20077569 0801.4338

    ADS  Google Scholar 

  • Dadina M, Cappi M (2004) Complex absorption hides a Type II QSO in IRAS 13197-1627. Astron Astrophys 413: 921–927. doi:10.1051/0004-6361:20031561 arXiv:astro-ph/0310272

    ADS  Google Scholar 

  • Dadina M, Cappi M, Malaguti G, Ponti G, de Rosa A (2005) X-ray absorption lines suggest matter infalling onto the central black-hole of Mrk 509. Astron Astrophys 442: 461–468. doi:10.1051/0004-6361:20042487 arXiv:astro-ph/0506697

    ADS  Google Scholar 

  • den Herder JW, Brinkman AC, Kahn SM, Branduardi-Raymont G, Thomsen K, Aarts H, Audard M, Bixler JV, den Boggende AJ, Cottam J, Decker T, Dubbeldam L, Erd C, Goulooze H, Güdel M, Guttridge P, Hailey CJ, Janabi KA, Kaastra JS, de Korte PAJ, van Leeuwen BJ, Mauche McCalden AJ, Mewe R, Naber A, Paerels FB, Peterson JR, Rasmussen AP, Rees K, Sakelliou I, Sako M, Spodek J, Stern M, Tamura T, Tandy J, de Vries CP, Welch S, Zehnder A (2001) The reflection grating spectrometer on board XMM-Newton. Astron Astrophys 365: L7–L17. doi:10.1051/0004-6361:20000058

    ADS  Google Scholar 

  • Done C, Nayakshin S (2007) Can the soft excess in AGN originate from disc reflection?. Mon Not RAS 377: L59–L63. doi:10.1111/j.1745-3933.2007.00303.x arXiv:astro-ph/0701410

    ADS  Google Scholar 

  • Dovčiak M, Bianchi S, Guainazzi M, Karas V, Matt G (2004) Relativistic spectral features from X-ray-illuminated spots and the measure of the black hole mass in active galactic nuclei. Mon Not RAS 350: 745–755. doi:10.1111/j.1365-2966.2004.07683.x arXiv:astro-ph/0401607

    ADS  Google Scholar 

  • Dovčiak M, Karas V, Matt G, Goosmann RW (2008) Variation in the primary and reprocessed radiation from an orbiting spot around a black hole. Mon Not RAS 384: 361–369. doi:10.1111/j.1365-2966.2007.12713.x 0712.1122

    ADS  Google Scholar 

  • Elvis M, Maccacaro T, Wilson AS, Ward MJ, Penston MV, Fosbury RAE, Perola GC (1978) Seyfert galaxies as X-ray sources. Mon Not RAS 183: 129–157

    ADS  Google Scholar 

  • Ercolano B, Young PR, Drake JJ, Raymond JC (2008) X-ray enabled MOCASSIN: a three-dimensional code for photoionized media. Astrophys J Suppl 175: 534–542. doi:10.1086/524378 0710.2103

    ADS  Google Scholar 

  • Fabian AC (1994) Hot plasmas and the generation of gamma rays. Astrophys J Suppl 92: 555–558. doi:10.1086/192015

    ADS  Google Scholar 

  • Fabian AC (2008) XMM-Newton and broad iron lines. Astronomische Nachrichten 329: 155–161. doi:10.1002/asna.200710902 arXiv:0711.2976

    ADS  Google Scholar 

  • Fabian AC, Vaughan S (2003) The iron line in MCG-6-30-15 from XMM-Newton: evidence for gravitational light bending. Mon Not RAS 340: L28–L32. doi:10.1046/j.1365-8711.2003.06465.x arXiv:astro-ph/0301588

    ADS  Google Scholar 

  • Fabian AC, Rees MJ, Stella L, White NE (1989) X-ray fluorescence from the inner disc in Cygnus X-1. Mon Not RAS 238: 729–736

    ADS  Google Scholar 

  • Fabian AC, Iwasawa K, Reynolds CS, Young AJ (2000) Broad iron lines in active galactic nuclei. Publ ASP 112: 1145–1161 arXiv:astro-ph/0004366

    ADS  Google Scholar 

  • Ferland GJ, Rees MJ (1988) Radiative equilibrium of high-density clouds with application to active galactic nucleus continua. Astrophys J 332: 141–156. doi:10.1086/166639

    ADS  Google Scholar 

  • Ferland GJ, Peterson BM, Horne K, Welsh WF, Nahar SN (1992) Anisotropic line emission and the geometry of the broad-line region in active galactic nuclei. Astrophys J 387: 95–108. doi:10.1086/171063

    ADS  Google Scholar 

  • Ferland GJ, Korista KT, Verner DA, Ferguson JW, Kingdon JB, Verner EM (1998) CLOUDY 90: numerical simulation of plasmas and their spectra. Publ ASP 110: 761–778

    ADS  Google Scholar 

  • Ferrarese L, Merritt D (2000) A fundamental relation between supermassive black holes and their host galaxies. Astrophys J Lett 539: L9–L12. doi:10.1086/312838 arXiv:astro-ph/0006053

    ADS  Google Scholar 

  • Fiore F, Perola GC, Romano M (1990) X-ray spectral variations in NGC 4151. Mon Not RAS 243: 522–528

    ADS  Google Scholar 

  • Gaskell CM (1982) A redshift difference between high and low ionization emission-line regions in QSOs—evidence for radial motions. Astrophys J 263: 79–86. doi:10.1086/160481

    ADS  Google Scholar 

  • Gebhardt K, Bender R, Bower G, Dressler A, Faber SM, Filippenko AV, Green R, Grillmair C, Ho LC, Kormendy J, Lauer TR, Magorrian J, Pinkney J, Richstone D, Tremaine S (2000) A relationship between nuclear black hole mass and galaxy velocity dispersion. Astrophys J Lett 539: L13–L16. doi:10.1086/312840 arXiv:astro-ph/0006289

    ADS  Google Scholar 

  • George IM, Fabian AC (1991) X-ray reflection from cold matter in active galactic nuclei and X-ray binaries. Mon Not RAS 249: 352–367

    ADS  Google Scholar 

  • George IM, Turner TJ, Netzer H, Nandra K, Mushotzky RF, Yaqoob T (1998) ASCA observations of seyfert 1 galaxies. III. The evidence for absorption and emission due to photoionized gas. Astrophys J Suppl 114: 73–120. doi:10.1086/313067 arXiv:astro-ph/9708046

    Google Scholar 

  • Ghisellini G, Haardt F, Matt G (1994) The contribution of the obscuring torus to the X-ray spectrum of seyfert galaxies—a test for the unification model. Mon Not RAS 267: 743–754 arXiv:astro-ph/9401044

    ADS  Google Scholar 

  • Ghosh KK, Soundararajaperumal S, Kalai Selvi M, Sivarani T (1992) X-ray spectrum of NGC 3783—detection of soft excess and an emission line. Astron Astrophys 255: 119–123

    ADS  Google Scholar 

  • Giacconi R, Murray S, Gursky H, Kellogg E, Schreier E, Matilsky T, Koch D, Tananbaum H (1974) The third UHURU catalog of X-ray sources. Astrophys J Suppl 27: 37–64

    ADS  Google Scholar 

  • Gierliński M, Done C (2004) Is the soft excess in active galactic nuclei real?. Mon Not RAS 349: L7–L11. doi:10.1111/j.1365-2966.2004.07687.x arXiv:astro-ph/0312271

    ADS  Google Scholar 

  • Gonçalves AC, Collin S, Dumont AM, Mouchet M, Różańska A, Chevallier L, Goosmann RW (2006) A new model for the Warm Absorber in NGC 3783: a single medium in total pressure equilibrium. Astron Astrophys 451: L23–L26. doi:10.1051/0004-6361:20064849 arXiv:astro-ph/0603641

    ADS  Google Scholar 

  • Gondoin P, Barr P, Lumb D, Oosterbroek T, Orr A, Parmar AN (2001) Simultaneous XMM-Newton and BeppoSAX observation of the Seyfert I galaxy IC 4329A. Astron Astrophys 378: 806–816. doi:10.1051/0004-6361:20011258

    ADS  Google Scholar 

  • Goosmann RW, Mouchet M, Czerny B, Dovčiak M, Karas V, Różańska A, Dumont AM (2007) Iron lines from transient and persisting hot spots on AGN accretion disks. Astron Astrophys 475: 155–168. doi:10.1051/0004-6361:20078273 0709.1356

    ADS  Google Scholar 

  • Graham AW, Erwin P, Caon N, Trujillo I (2001) A correlation between galaxy light concentration and supermassive black hole mass. Astrophys J Lett 563: L11–L14. doi:10.1086/338500 arXiv:astro-ph/0111152

    ADS  Google Scholar 

  • Green AR, McHardy IM, Lehto HJ (1993) On the nature of rapid X-ray variability in active galactic nuclei. Mon Not RAS 265: 664–680

    ADS  Google Scholar 

  • Guainazzi M (2003) The history of the iron Kα line profile in the Piccinotti AGN ESO 198-G24. Astron Astrophys 401: 903–910. doi:10.1051/0004-6361:20030160 arXiv:astro-ph/0302117

    ADS  Google Scholar 

  • Guainazzi M, Matsuoka M, Piro L, Mihara T, Yamauchi M (1994) Iron line emission and two-component spectral behavior in the ASCA observation of the Seyfert 1 galaxy NGC 7469. Astrophys J Lett 436: L35–L39. doi:10.1086/187627

    ADS  Google Scholar 

  • Guilbert PW, Rees MJ (1988) ‘Cold’ material in non-thermal sources. Mon Not RAS 233: 475–484

    ADS  Google Scholar 

  • Haardt F, Maraschi L (1991) A two-phase model for the X-ray emission from Seyfert galaxies. Astrophys J Lett 380: L51–L54. doi:10.1086/186171

    ADS  Google Scholar 

  • Haardt F, Maraschi L (1993) X-ray spectra from two-phase accretion disks. Astrophys J 413: 507–517. doi:10.1086/173020

    ADS  Google Scholar 

  • Haardt F, Maraschi L, Ghisellini G (1997) X-ray variability and correlations in the two-phase disk-corona model for seyfert galaxies. Astrophys J 476: 620–631. doi:10.1086/303656 arXiv:astro-ph/9609050

    ADS  Google Scholar 

  • Halpern JP (1984) Variable X-ray absorption in the QSO MR 2251-178. Astrophys J 281: 90–94. doi:10.1086/162077

    ADS  Google Scholar 

  • Heckman TM (1980) An optical and radio survey of the nuclei of bright galaxies—activity in normal galactic nuclei. Astron Astrophys 87: 152–164

    ADS  Google Scholar 

  • Heckman TM, Kauffmann G, Brinchmann J, Charlot S, Tremonti C, White SDM (2004) Present-day growth of black holes and bulges: the sloan digital sky survey perspective. Astrophys J 613: 109–118. doi:10.1086/422872 arXiv:astro-ph/0406218

    ADS  Google Scholar 

  • Ho LC (1999) The spectral energy distributions of low-luminosity active galactic nuclei. Astrophys J 516: 672–682. doi:10.1086/307137 arXiv:astro-ph/9905012

    ADS  Google Scholar 

  • Ho LC (2008) Nuclear activity in nearby galaxies. ArXiv e-prints 803, 0803.2268

  • Różańska Holt SS, Mushotzky RF, Boldt EA, Serlemitsos PJ, Becker RH, Szymkowiak AE, White NE (1980) X-ray spectral constraints on the broad-line cloud geometry of NGC 4151. Astrophys J Lett 241: L13–L17. doi:10.1086/183350

    ADS  Google Scholar 

  • Inoue H, Matsumoto C (2003) Another interpretation of the disk-line profile for the Seyfert 1 galaxy MCG-6-30-15. Publ ASJ 55: 625–629

    ADS  Google Scholar 

  • Iwasawa K, Lee JC, Young AJ, Reynolds CS, Fabian AC (2004a) The hard X-ray spectrum of the Seyfert galaxy IRAS 18325-5926: reflection from an ionized disc and variable iron K emission. Mon Not RAS 347: 411–420. doi:10.1111/j.1365-2966.2004.07206.x arXiv:astro-ph/0309432

    ADS  Google Scholar 

  • Iwasawa K, Miniutti G, Fabian AC (2004b) Flux and energy modulation of redshifted iron emission in NGC 3516: implications for the black hole mass. Mon Not RAS 355: 1073–1079. doi:10.1111/j.1365-2966.2004.08392.x arXiv:astro-ph/0409293

    ADS  Google Scholar 

  • Kaastra JS, Barr P (1989) Soft and hard X-ray variability from the accretion disk of NGC 5548. Astron Astrophys 226: 59–68

    ADS  Google Scholar 

  • Kaastra JS, Mewe R, Liedahl DA, Komossa S, Brinkman AC (2000) X-ray absorption lines in the Seyfert 1 galaxy NGC 5548 discovered with Chandra-LETGS. Astron Astrophys 354: L83–L86 arXiv:astro-ph/0002345

    ADS  Google Scholar 

  • Kaastra JS, Mewe R, Raassen T (2003) New results on X-ray models and atomic data. Atomic Data for X-Ray Astronomy, 25th meeting of the IAU, Joint Discussion 17, 22 July 2003, Sydney, Australia 17

  • Kallman T, Bautista M (2001) Photoionization and high-density gas. Astrophys J Suppl 133: 221–253. doi:10.1086/319184

    ADS  Google Scholar 

  • Kallman TR, Palmeri P, Bautista MA, Mendoza C, Krolik JH (2004) Photoionization Modeling and the K Lines of Iron. Astrophys J Suppl 155: 675–701. doi:10.1086/424039 arXiv:astro-ph/0405210

    ADS  Google Scholar 

  • Karas V, Lanza A, Vokrouhlicky D (1995) Emission-line profiles from self-gravitating thin disks. Astrophys J 440: 108–115. doi:10.1086/175252 arXiv:astro-ph/9409035

    ADS  Google Scholar 

  • Kaspi S, Smith PS, Netzer H, Maoz D, Jannuzi BT, Giveon U (2000) Reverberation measurements for 17 Quasars and the size-mass-luminosity relations in active galactic nuclei. Astrophys J 533: 631–649. doi:10.1086/308704 arXiv:astro-ph/9911476

    ADS  Google Scholar 

  • Kaspi S, Brandt WN, Netzer H, George IM, Chartas G, Behar E, Sambruna RM, Garmire GP, Nousek JA (2001) High-resolution X-ray spectroscopy and modeling of the absorbing and emitting outflow in NGC 3783. Astrophys J 554: 216–232. doi:10.1086/321333 arXiv:astro-ph/0101540

    ADS  Google Scholar 

  • Kaspi S, Brandt WN, George IM, Netzer H, Crenshaw DM, Gabel JR, Hamann FW, Kaiser ME, Koratkar A, Kraemer SB, Kriss GA, Mathur S, Mushotzky RF, Nandra K, Peterson BM, Shields JC, Turner TJ, Zheng W (2002) The ionized gas and nuclear environment in NGC 3783. I. Time-averaged 900 kilosecond chandra grating spectroscopy. Astrophys J 574: 643–662. doi:10.1086/341113 arXiv:astro-ph/0203263

    ADS  Google Scholar 

  • King AR, Pounds KA (2003) Black hole winds. Mon Not RAS 345: 657–659. doi:10.1046/j.1365-8711.2003.06980.x arXiv:astro-ph/0305541

    ADS  Google Scholar 

  • Kormendy J, Richstone D (1995) Inward bound—the search for supermassive black holes in galactic nuclei. Annu Rev Astron Astrophys 33: 581–624. doi:10.1146/annurev.aa.33.090195.003053

    ADS  Google Scholar 

  • Koyama K, Tsunemi H, Dotani T, Bautz MW, Hayashida K, Tsuru TG, Matsumoto H, Ogawara Y, Ricker GR, Doty J, Kissel SE, Foster R, Nakajima H, Yamaguchi H, Mori H, Sakano M, Hamaguchi K, Nishiuchi M, Miyata E, Torii K, Namiki M, Katsuda S, Matsuura D, Miyauchi T, Anabuki N, Tawa N, Ozaki M, Murakami H, Maeda Y, Ichikawa Y, Prigozhin GY, Boughan EA, Lamarr B, Miller ED, Burke BE, Gregory JA, Pillsbury A, Bamba A, Hiraga JS, Senda A, Katayama H, Kitamoto S, Tsujimoto M, Kohmura T, Tsuboi Y, Awaki H (2007) X-ray imaging spectrometer (XIS) on board Suzaku. Publ ASJ 59: 23–33

    Google Scholar 

  • Kraemer SB, George IM, Crenshaw DM, Gabel JR, Turner TJ, Gull TR, Hutchings JB, Kriss GA, Mushotzky RF, Netzer H, Peterson BM, Behar E (2005) Simultaneous ultraviolet and X-ray observations of seyfert galaxy NGC 4151. I. Physical conditions in the X-ray absorbers. Astrophys J 633: 693–705. doi:10.1086/466522 arXiv:astro-ph/0507354

    ADS  Google Scholar 

  • Krolik JH, Kallman TR (1987) Fe K features as probes of the nuclear reflection region in Seyfert galaxies. Astrophys J Lett 320: L5–L8. doi:10.1086/184966

    ADS  Google Scholar 

  • Krolik JH, Kriss GA (1995) Observable properties of X-ray–heated winds in active galactic nuclei: warm reflectors and warm absorbers. Astrophys J 447: 512–525. doi:10.1086/175896 arXiv:astro-ph/9501089

    ADS  Google Scholar 

  • Krolik JH, McKee CF, Tarter CB (1981) Two-phase models of quasar emission line regions. Astrophys J 249: 422–442. doi:10.1086/159303

    ADS  Google Scholar 

  • Krongold Y, Nicastro F, Brickhouse NS, Elvis M, Liedahl DA, Mathur S (2003) Toward a self-consistent model of the ionized absorber in NGC 3783. Astrophys J 597: 832–850. doi:10.1086/378639 arXiv:astro-ph/0306460

    ADS  Google Scholar 

  • Krongold Y, Nicastro F, Brickhouse NS, Elvis M, Mathur S (2005) Opacity variations in the ionized absorption in NGC 3783: a compact absorber. Astrophys J 622: 842–846. doi:10.1086/427621 arXiv:astro-ph/0411554

    ADS  Google Scholar 

  • Laor A (1991) Line profiles from a disk around a rotating black hole. Astrophys J 376: 90–94. doi:10.1086/170257

    ADS  Google Scholar 

  • Larsson J, Miniutti G, Fabian AC, Miller JM, Reynolds CS, Ponti G (2008) Suzaku observations of Markarian 335: evidence for a distributed reflector. Mon Not RAS 384: 1316–1326. doi:10.1111/j.1365-2966.2008.12844.x 0712.1906

    ADS  Google Scholar 

  • Lawrence A, Elvis M (1982) Obscuration and the various kinds of Seyfert galaxies. Astrophys J 256: 410–426. doi:10.1086/159918

    ADS  Google Scholar 

  • Lawrence A, Watson MG, Pounds KA, Elvis M (1985) Continuous rapid X-ray variability and spectral changes in NGC 4051. Mon Not RAS 217: 685–699

    ADS  Google Scholar 

  • Leahy DA, Creighton J (1993) Montecarlo simulations of X-ray spectra for internally illuminated spherical matter distributions. Mon Not RAS 263: 314–322

    ADS  Google Scholar 

  • Lee JC, Ogle PM, Canizares CR, Marshall HL, Schulz NS, Morales R, Fabian AC, Iwasawa K (2001) Revealing the dusty warm absorber in MCG-6-30-15 with the Chandra high-energy transmission grating. Astrophys J Lett 554: L13–L17. doi:10.1086/320912 arXiv:astro-ph/0101065

    ADS  Google Scholar 

  • Lee JC, Iwasawa K, Houck JC, Fabian AC, Marshall HL, Canizares CR (2002) The shape of the relativistic iron Kα line from MCG-6-30-15 measured with the Chandra high energy transmission grating spectrometer and the Rossi X-ray timing explorer. Astrophys J Lett 570: L47–L50. doi:10.1086/340992

    ADS  Google Scholar 

  • Leighly KM (1999) A comprehensive spectral and variability study of narrow-line Seyfert 1 galaxies observed by ASCA. I. Observations and time series analysis. Astrophys J Suppl 125: 297–316. doi:10.1086/313277 arXiv:astro-ph/9907294

    ADS  Google Scholar 

  • Leighly KM, Pounds KA, Turner TJ (1989) A search for iron features in the EXOSAT spectral survey sources. In: Hunt J, Battrick B (eds) Two topics in X-ray astronomy, X-ray binaries, vol 1. AGN and the X-ray background, vol 2. ESA Special Publication, vol 296, pp 961–967

  • Liedahl DA (2005) Resonant Auger Destruction and Iron Kα Spectra in Compact X-ray Sources. In: Smith R (ed) X-ray diagnostics of astrophysical plasmas: theory, experiment, and observation. American Institute of Physics Conference Series, vol 774, pp 99–108. doi:10.1063/1.1960918

  • Lightman AP, White TR (1988) Effects of cold matter in active galactic nuclei - A broad hump in the X-ray spectra. Astrophys J 335: 57–66. doi:10.1086/166905

    ADS  Google Scholar 

  • Longinotti AL, Nandra K, Petrucci PO, O’Neill PM (2004) On the variability of the iron Kα line in Mrk 841. Mon Not RAS 355: 929–934. doi:10.1111/j.1365-2966.2004.08369.x arXiv:astro-ph/0409459

    ADS  Google Scholar 

  • Longinotti AL, Sim SA, Nandra K, Cappi M (2007) Evidence for relativistic features in the X-ray spectrum of Mrk 335. Mon Not RAS 374: 237–247. doi:10.1111/j.1365-2966.2006.11138.x arXiv:astro-ph/0609414

    ADS  Google Scholar 

  • Magdziarz P, Zdziarski AA (1995) Angle-dependent Compton reflection of X-rays and gamma-rays. Mon Not RAS 273: 837–848

    ADS  Google Scholar 

  • Magorrian J, Tremaine S, Richstone D, Bender R, Bower G, Dressler A, Faber SM, Gebhardt K, Green R, Grillmair C, Kormendy J, Lauer T (1998) The demography of massive dark objects in galaxy centers. Astron J 115: 2285–2305. doi:10.1086/300353 arXiv:astro-ph/9708072

    ADS  Google Scholar 

  • Marconi A, Hunt LK (2003) The relation between black hole mass, bulge mass, and near-infrared luminosity. Astrophys J Lett 589: L21–L24. doi:10.1086/375804 arXiv:astro-ph/0304274

    ADS  Google Scholar 

  • Marconi A, Risaliti G, Gilli R, Hunt LK, Maiolino R, Salvati M (2004) Local supermassive black holes, relics of active galactic nuclei and the X-ray background. Mon Not RAS 351: 169–185. doi:10.1111/j.1365-2966.2004.07765.x arXiv:astro-ph/0311619

    ADS  Google Scholar 

  • Markowitz A, Reeves JN, Braito V (2006) Fe K emission and absorption in the XMM-EPIC spectrum of the Seyfert Galaxy IC 4329a. Astrophys J 646: 783–800. doi:10.1086/505107 arXiv:astro-ph/0604353

    ADS  Google Scholar 

  • Marshall N, Warwick RS, Pounds KA (1981) The variability of X-ray emission from active galaxies. Mon Not RAS 194: 987–1002

    ADS  Google Scholar 

  • Matsumoto C, Inoue H, Fabian AC, Iwasawa K (2003) Iron line properties of the Seyfert 1 galaxy MCG-6-30-15 observed with ASCA. Publ ASJ 55: 615–623

    ADS  Google Scholar 

  • Matsuoka M, Piro L, Yamauchi M, Murakami T (1990) X-ray spectral variability and complex absorption in the Seyfert 1 galaxies NGC 4051 and MCG-6-30-15. Astrophys J 361: 440–458. doi:10.1086/169209

    ADS  Google Scholar 

  • Matsuoka M, Yamauchi M, Piro L (1991) A spectral signature of thick matter in the X-ray spectrum from the Seyfert 1 galaxy, IC4329A. Adv Space Res 11: 41–43. doi:10.1016/0273-1177(91)90147-C

    ADS  Google Scholar 

  • Matt G (1994) Iron K-alpha resonant absorption in warm absorbers around active galactic nuclei. Mon Not RAS 267: L17–L20

    ADS  Google Scholar 

  • Matt G, Perola GC, Piro L (1991) The iron line and high energy bump as X-ray signatures of cold matter in Seyfert 1 galaxies. Astron Astrophys 247: 25–34

    ADS  Google Scholar 

  • Matt G, Fabian AC, Reynolds CS (1997) Geometrical and chemical dependence of K-shell X-ray features. Mon Not RAS 289: 175–184

    ADS  Google Scholar 

  • Matt G, Pompilio F, La Franca F (1999) X-ray spectra transmitted through Compton-thick absorbers. New Astron 4: 191–195. doi:10.1016/S1384-1076(99)00021-4 arXiv:astro-ph/9904341

    ADS  Google Scholar 

  • McKernan B, Yaqoob T (1998) Occultation mapping of the central engine in the active galaxy MCG-6-30-15. Astrophys J Lett 501: L29–L32. doi:10.1086/311457 arXiv:astro-ph/9804265

    ADS  Google Scholar 

  • McKernan B, Yaqoob T, Reynolds CS (2005) Constraints on hot metals in the vicinity of the Galaxy. Mon Not RAS 361: 1337–1344. doi:10.1111/j.1365-2966.2005.09291.x arXiv:astro-ph/0506346

    ADS  Google Scholar 

  • McKernan B, Yaqoob T, Reynolds CS (2007) A soft X-ray study of type I active galactic nuclei observed with Chandra high-energy transmission grating spectrometer. Mon Not RAS 379: 1359–1372. doi:10.1111/j.1365-2966.2007.11993.x

    ADS  Google Scholar 

  • Merloni A, Malzac J, Fabian AC, Ross RR (2006) On the X-ray spectra of luminous, inhomogeneous accretion flows. Mon Not RAS 370: 1699–1712. doi:10.1111/j.1365-2966.2006.10676.x arXiv:astro-ph/0606262

    ADS  Google Scholar 

  • Middleton M, Done C, Gierliński M (2007) An absorption origin for the soft excess in Seyfert 1 active galactic nuclei. Mon Not RAS 381: 1426–1436. doi:10.1111/j.1365-2966.2007.12341.x 0704.2970

    ADS  Google Scholar 

  • Mihara T, Matsuoka M, Mushotzky RF, Kunieda H, Otani C, Miyamoto S, Yamauchi M (1994) Soft X-ray spectral features in the Seyfert 1 Galaxy NGC4051. Publ ASJ 46: L137–L140

    ADS  Google Scholar 

  • Miller L, Turner TJ, Reeves JN, George IM, Porquet D, Nandra K, Dovciak M (2006) Variable iron-line emission near the black hole of Markarian 766. Astron Astrophys 453: L13–L16. doi:10.1051/0004-6361:20065276 arXiv:astro-ph/0605130

    ADS  Google Scholar 

  • Miller L, Turner TJ, Reeves JN, George IM, Kraemer SB, Wingert B (2007) The variable X-ray spectrum of Markarian 766. I. Principal components analysis. Astron Astrophys 463: 131–143. doi:10.1051/0004-6361:20066548 arXiv:astro-ph/0611673

    ADS  Google Scholar 

  • Miller L, Turner TJ, Reeves JN (2008) An absorption origin for the X-ray spectral variability of MCG-6-30-15. Astron Astrophys 483: 437–452. doi:10.1051/0004-6361:200809590 0803.2680

    ADS  Google Scholar 

  • Mineshige S, Kawaguchi T, Takeuchi M, Hayashida K (2000) Slim-disk model for soft X-ray excess and variability of narrow-line Seyfert 1 galaxies. Publ ASJ 52: 499–508 arXiv:astro-ph/0003017

    ADS  Google Scholar 

  • Miniutti G, Fabian AC (2004) A light bending model for the X-ray temporal and spectral properties of accreting black holes. Mon Not RAS 349: 1435–1448. doi:10.1111/j.1365-2966.2004.07611.x arXiv:astro-ph/0309064

    ADS  Google Scholar 

  • Miniutti G, Fabian AC, Goyder R, Lasenby AN (2003) The lack of variability of the iron line in MCG-6-30-15: general relativistic effects. Mon Not RAS 344: L22–L26. doi:10.1046/j.1365-8711.2003.06988.x arXiv:astro-ph/0307163

    ADS  Google Scholar 

  • Miniutti G, Fabian AC, Anabuki N, Crummy J, Fukazawa Y, Gallo L, Haba Y, Hayashida K, Holt S, Kunieda H, Larsson J, Markowitz A, Matsumoto C, Ohno M, Reeves JN, Takahashi T, Tanaka Y, Terashima Y, Torii K, Ueda Y, Ushio M, Watanabe S, Yamauchi M, Yaqoob T (2007) Suzaku observations of the hard X-ray variability of MCG-6-30-15: the effects of strong gravity around a Kerr black hole. Publ ASJ 59: 315–325 arXiv:astro-ph/0609521

    Google Scholar 

  • Mitsuda K, Bautz M, Inoue H, Kelley RL, Koyama K, Kunieda H, Makishima K, Ogawara Y, Petre R, Takahashi T, Tsunemi H, White NE, Anabuki N, Angelini L, Arnaud K, Awaki H, Bamba A, Boyce K, Brown GV, Chan KW, Cottam J, Dotani T, Doty J, Ebisawa K, Ezoe Y, Fabian AC, Figueroa E, Fujimoto R, Fukazawa Y, Furusho T, Furuzawa A, Gendreau K, Griffiths RE, Haba Y, Hamaguchi K, Harrus I, Hasinger G, Hatsukade I, Hayashida K, Henry PJ, Hiraga JS, Holt SS, Hornschemeier A, Hughes JP, Hwang U, Ishida M, Ishisaki Y, Isobe N, Itoh M, Iyomoto N, Kahn SM, Kamae T, Katagiri H, Kataoka J, Katayama H, Kawai N, Kilbourne C, Kinugasa K, Kissel S, Kitamoto S, Kohama M, Kohmura T, Kokubun M, Kotani T, Kotoku J, Kubota A, Madejski GM, Maeda Y, Makino F, Markowitz A, Matsumoto C, Matsumoto H, Matsuoka M, Matsushita K, McCammon D, Mihara T, Misaki K, Miyata E, Mizuno T, Mori K, Mori H, Morii M, Moseley H, Mukai K, Murakami H, Murakami T, Mushotzky R, Nagase F, Namiki M, Negoro H, Nakazawa K, Nousek JA, Okajima T, Ogasaka Y, Ohashi T, Oshima T, Ota N, Ozaki M, Ozawa H, Parmar AN, Pence WD, Porter FS, Reeves JN, Ricker GR, Sakurai I, Sanders WT, Senda A, Serlemitsos P, Shibata R, Soong Y, Smith R, Suzuki M, Szymkowiak AE, Takahashi H, Tamagawa T, Tamura K, Tamura T, Tanaka Y, Tashiro M, Tawara Y, Terada Y, Terashima Y, Tomida H, Torii K, Tsuboi Y, Tsujimoto M, Tsuru TG, Turner MJL, Ueda Y, Ueno S, Ueno M, Uno S, Urata Y, Watanabe S, Yamamoto N, Yamaoka K, Yamasaki NY, Yamashita K, Yamauchi M, Yamauchi S, Yaqoob T, Yonetoku D, Yoshida A (2007) The X-ray observatory Suzaku. Publ ASJ 59: 1–7

    ADS  Google Scholar 

  • Miyoshi S, Hayakawa S, Kunieda H, Nagase F, Tawara Y (1986) X-ray observation of AGN’s from TENMA. Astrophys Space Sci 119: 185–190

    ADS  Google Scholar 

  • Morales R, Fabian AC (2002) Weighing black holes with warm absorbers. Mon Not RAS 329: 209–220. doi:10.1046/j.1365-8711.2002.04951.x arXiv:astro-ph/0109050

    ADS  Google Scholar 

  • Murray N, Chiang J (1998) Photoionization of disk winds. Astrophys J 494: 125–138. doi:10.1086/305183

    ADS  Google Scholar 

  • Mushotzky RF (1976) Observations of hard X-rays from extra-galactic objects. PhD thesis, AA (California University, San Diego)

  • Mushotzky RF (1984) X-ray spectra and time variability of active galactic nuclei. Adv Space Res 3: 157–165. doi:10.1016/0273-1177(84)90081-4

    ADS  Google Scholar 

  • Mushotzky RF, Holt SS, Serlemitsos PJ (1978) X-ray observations of a flare in NGC 4151 from OSO 8. Astrophys J Lett 225: L115–L118. doi:10.1086/182806

    ADS  Google Scholar 

  • Nandra K (2006) On the origin of the iron Kα line cores in active galactic nuclei. Mon Not RAS 368: L62–L66. doi:10.1111/j.1745-3933.2006.00158.x arXiv:astro-ph/0602081

    ADS  Google Scholar 

  • Nandra K, George IM (1994) X-ray reprocessing by cold clouds in active galactic nuclei. Mon Not RAS 267: 974–980

    ADS  Google Scholar 

  • Nandra K, Pounds KA (1992) Highly ionized gas in the nucleus of the active galaxy MCG-6-30-15. Nature 359: 215–216. doi:10.1038/359215a0

    ADS  Google Scholar 

  • Nandra K, Pounds KA (1994) GINGA observations of the X-ray spectra of Seyfert galaxies. Mon Not RAS 268: 405–429

    ADS  Google Scholar 

  • Nandra K, Pounds KA, Stewart GC, Fabian AC, Rees MJ (1989) Detection of iron features in the X-ray spectrum of the Seyfert I galaxy MCG-6-30-15. Mon Not RAS 236: 39P–46P

    ADS  Google Scholar 

  • Nandra K, Fabian AC, George IM, Branduardi-Raymont G, Lawrence A, Mason KO, McHardy IM, Pounds KA, Stewart GC, Ward MJ, Warwick RS (1993) A ROSAT observation of NGC 5548. Mon Not RAS 260: 504–512

    ADS  Google Scholar 

  • Nandra K, George IM, Mushotzky RF, Turner TJ, Yaqoob T (1997) ASCA observations of Seyfert 1 galaxies. II. Relativistic iron K alpha emission. Astrophys J 477: 602–622. doi:10.1086/303721 arXiv:astro-ph/9606169

    ADS  Google Scholar 

  • Nandra K, O’Neill PM, George IM, Reeves JN (2007) An XMM-Newton survey of broad iron lines in Seyfert galaxies. Mon Not RAS 382: 194–228. doi:10.1111/j.1365-2966.2007.12331.x 0708.1305

    ADS  Google Scholar 

  • Narayan R, Yi I (1994) Advection-dominated accretion: a self-similar solution. Astrophys J Lett 428: L13–L16. doi:10.1086/187381 arXiv:astro-ph/9403052

    ADS  Google Scholar 

  • Nayakshin S, Kazanas D (2002) On time-dependent X-ray reflection by photoionized accretion disks: implications for Fe Kα line reverberation studies of active galactic nuclei. Astrophys J 567: 85–96. doi:10.1086/338333 arXiv:astro-ph/0106450

    ADS  Google Scholar 

  • Nayakshin S, Kazanas D, Kallman TR (2000) Thermal instability and photoionized X-ray reflection in accretion disks. Astrophys J 537: 833–852. doi:10.1086/309054 arXiv:astro-ph/9909359

    ADS  Google Scholar 

  • Netzer H (1993) Ionized absorbers, ionized emitters, and the X-ray spectrum of active galactic nuclei. Astrophys J 411: 594–601. doi:10.1086/172861

    ADS  Google Scholar 

  • Netzer H (1996) X-ray lines in active galactic nuclei and photoionized gases. Astrophys J 473: 781–796. doi:10.1086/178190

    ADS  Google Scholar 

  • Netzer H, Chelouche D, George IM, Turner TJ, Crenshaw DM, Kraemer SB, Nandra K (2002) The density and location of the X-ray-absorbing gas in NGC 3516. Astrophys J 571: 256–264. doi:10.1086/338967 arXiv:astro-ph/0112027

    ADS  Google Scholar 

  • Netzer H, Kaspi S, Behar E, Brandt WN, Chelouche D, George IM, Crenshaw DM, Gabel JR, Hamann FW, Kraemer SB, Kriss GA, Nandra K, Peterson BM, Shields JC, Turner TJ (2003) The ionized gas and nuclear environment in NGC 3783. IV. Variability and modeling of the 900 kilosecond chandra spectrum. Astrophys J 599: 933–948. doi:10.1086/379508 arXiv:astro-ph/0309096

    ADS  Google Scholar 

  • Nicastro F, Fiore F, Matt G (1999) Resonant absorption in the active galactic nucleus spectra emerging from photoionized gas: differences between steep and flat ionizing continua. Astrophys J 517: 108–122. doi:10.1086/307187 arXiv:astro-ph/9812392

    ADS  Google Scholar 

  • Onken CA, Ferrarese L, Merritt D, Peterson BM, Pogge RW, Vestergaard M, Wandel A (2004) Supermassive black holes in active galactic nuclei. II. Calibration of the black hole mass-velocity dispersion relationship for active galactic nuclei. Astrophys J 615: 645–651. doi:10.1086/424655 arXiv:astro-ph/0407297

    ADS  Google Scholar 

  • Orr A, Molendi S, Fiore F, Grandi P, Parmar AN, Owens A (1997) Soft X-ray observations of the complex warm absorber in MCG-6-30-15 with BeppoSAX. Astron Astrophys 324: L77–L80 arXiv:astro-ph/9706133

    ADS  Google Scholar 

  • Osterbrock DE, Ferland GJ (2006) Astrophysics of gaseous nebulae and active galactic nuclei. In: Osterbrock DE, Ferland GJ (eds) Astrophysics of gaseous nebulae and active galactic nuclei, 2nd edn. University Science Books, Sausalito, CA

  • Osterbrock DE, Pogge RW (1985) The spectra of narrow-line Seyfert 1 galaxies. Astrophys J 297: 166–176. doi:10.1086/163513

    ADS  Google Scholar 

  • Otani C, Kii T, Reynolds CS, Fabian AC, Iwasawa K, Hayashida K, Inoue H, Kunieda H, Makino F, Matsuoka M, Tanaka Y (1996) The variable O, VIII warm absorber in MCG-6-30-15. Publ ASJ 48: 211–218 arXiv:astro-ph/9511063

    ADS  Google Scholar 

  • Padovani P, Rafanelli P (1988) Mass-luminosity relationships and accretion rates for Seyfert 1 galaxies and quasars. Astron Astrophys 205: 53–70

    ADS  Google Scholar 

  • Page KL, Pounds KA, Reeves JN, O’Brien PT (2002) The highly variable X-ray spectrum of the luminous Seyfert 1 galaxy 1H 0419-577. Mon Not RAS 330: L1–L5. doi:10.1046/j.1365-8711.2002.05184.x arXiv:astro-ph/0112215

    ADS  Google Scholar 

  • Palmeri P, Mendoza C, Kallman TR, Bautista MA, Meléndez M (2003) Modeling of iron K lines: radiative and Auger decay data for Fe II–Fe IX. Astron Astrophys 410: 359–364. doi:10.1051/0004-6361:20031262 arXiv:astro-ph/0306321

    ADS  Google Scholar 

  • Pan HC, Stewart GC, Pounds KA (1990) The variable X-ray absorption and soft X-ray excess of the QSO MR2251 - 178. Mon Not RAS 242: 177–187

    ADS  Google Scholar 

  • Panessa F, Bassani L (2002) Unabsorbed Seyfert 2 galaxies. Astron Astrophys 394: 435–442. doi:10.1051/0004-6361:20021161 arXiv:astro-ph/0208496

    ADS  Google Scholar 

  • Papadakis IE, Petrucci PO, Maraschi L, McHardy IM, Uttley P, Haardt F (2002) Long-term spectral variability of seyfert galaxies from Rossi X-ray timing explorer color-flux diagrams. Astrophys J 573: 92–104. doi:10.1086/340497 arXiv:astro-ph/0202498

    ADS  Google Scholar 

  • Peterson BM (1993) Reverberation mapping of active galactic nuclei. Publ ASP 105: 247–268

    ADS  Google Scholar 

  • Peterson BM, Wandel A (2000) Evidence for supermassive black holes in active galactic nuclei from emission-line reverberation. Astrophys J Lett 540: L13–L16. doi:10.1086/312862 arXiv:astro-ph/0007147

    ADS  Google Scholar 

  • Peterson BM, Ferrarese L, Gilbert KM, Kaspi S, Malkan MA, Maoz D, Merritt D, Netzer H, Onken CA, Pogge RW, Vestergaard M, Wandel A (2004) Central masses and broad-line region sizes of active galactic nuclei. II. A homogeneous analysis of a large reverberation-mapping database. Astrophys J 613: 682–699. doi:10.1086/423269 arXiv:astro-ph/0407299

    ADS  Google Scholar 

  • Petrucci PO, Henri G, Maraschi L, Ferrando P, Matt G, Mouchet M, Perola C, Collin S, Dumont AM, Haardt F, Koch-Miramond L (2002) A rapidly variable narrow X-ray iron line in Mkn 841. Astron Astrophys 388: L5–L8. doi:10.1051/0004-6361:20020534 arXiv:astro-ph/0204095

    ADS  Google Scholar 

  • Piro L, Massaro E, Perola GC, Molteni D (1988) An exceptional change in the X-ray flux and spectrum of the Seyfert 1 galaxy E1615 + 061. Astrophys J Lett 325: L25–L28. doi:10.1086/185102

    ADS  Google Scholar 

  • Piro L, Yamauchi M, Matsuoka M (1990) X-ray spectral signatures of very thick cold matter in the spectra of the Seyfert 1 galaxies NGC 7469 and IC 4329A. Astrophys J Lett 360: L35–L38. doi:10.1086/185806

    ADS  Google Scholar 

  • Piro L, Yamauchi M, Matsuoka M (1992) X-ray spectral signatures of very thick cold matter in the spectra of Seyfert galaxies. Nuovo Cimento C Geophys Space Phys C 15: 811–818

    ADS  Google Scholar 

  • Ponti G, Cappi M, Dadina M, Malaguti G (2004) Mapping the inner regions of MCG-6-30-15 with XMM-Newton. Astron Astrophys 417: 451–459. doi:10.1051/0004-6361:20031758 arXiv:astro-ph/0312250

    ADS  Google Scholar 

  • Porquet D, Dubau J (2000) X-ray photoionized plasma diagnostics with helium-like ions. Application to warm absorber-emitter in active galactic nuclei. Astron Astrophys Suppl 143: 495–514. doi:10.1051/aas:2000192 arXiv:astro-ph/0002319

    ADS  Google Scholar 

  • Pounds KA, Reeves JN (2008) Resolving a broad PCygni line profile to quantify the fast outflow in the luminous Seyfert galaxy PG1211+143. ArXiv e-prints 0811.3108

  • Pounds KA, Turner TJ, Warwick RS (1986) Rapid X-ray variability of the Seyfert galaxy MCG-6-30-15. Mon Not RAS 221: 7P–12P

    ADS  Google Scholar 

  • Pounds KA, Nandra K, Stewart GC, Leighly K (1989) Iron features in the X-ray spectra of three Seyfert galaxies.. Mon Not RAS 240: 769–783

    ADS  Google Scholar 

  • Pounds KA, Nandra K, Stewart GC, George IM, Fabian AC (1990) X-ray reflection from cold matter in the nuclei of active galaxies. Nature 344: 132–133. doi:10.1038/344132a0

    ADS  Google Scholar 

  • Pounds KA, Nandra K, Fink HH, Makino F (1994) Constraining the complexities in Seyfert X-ray spectra—an analysis of simultaneous observations with GINGA and ROSAT. Mon Not RAS 267: 193–208

    ADS  Google Scholar 

  • Pounds KA, Done C, Osborne JP (1995) RE 1034+39: a high-state Seyfert galaxy?. Mon Not RAS 277: L5–L10

    ADS  Google Scholar 

  • Pounds KA, Reeves JN, King AR, Page KL, O’Brien PT, Turner MJL (2003) A high-velocity ionized outflow and XUV photosphere in the narrow emission line quasar PG1211+143. Mon Not RAS 345: 705–713. doi:10.1046/j.1365-8711.2003.07006.x arXiv:astro-ph/0303603

    ADS  Google Scholar 

  • Pounds KA, Reeves JN, Page KL, O’Brien PT (2004a) An XMM-Newton observation of the Seyfert 1 galaxy 1H 0419-577 in an extreme low state. Astrophys J 605: 670–676. doi:10.1086/382678 arXiv:astro-ph/0401026

    ADS  Google Scholar 

  • Pounds KA, Reeves JN, Page KL, O’Brien PT (2004b) Resolving the large-scale spectral variability of the luminous Seyfert 1 galaxy 1H 0419-577: evidence for a new emission component and absorption by cold dense matter. Astrophys J 616: 696–706. doi:10.1086/424992 arXiv:astro-ph/0407045

    ADS  Google Scholar 

  • Press WH, Teukolsky SA, Vetterling WT, Flannery BP (1992) Numerical recipes in FORTRAN. The art of scientific computing, 2nd edn. Cambridge University Press, Cambridge

  • Proga D, Kallman TR (2004) Dynamics of line-driven disk winds in active galactic nuclei. II. Effects of disk radiation. Astrophys J 616: 688–695. doi:10.1086/425117 arXiv:astro-ph/0408293

    ADS  Google Scholar 

  • Proga D, Stone JM, Kallman TR (2000) Dynamics of line-driven disk winds in active galactic nuclei. Astrophys J 543: 686–696. doi:10.1086/317154 arXiv:astro-ph/0005315

    ADS  Google Scholar 

  • Proga D, Ostriker JP, Kurosawa R (2008) Dynamics of rotating accretion flows irradiated by a quasar. Astrophys J 676: 101–112. doi:10.1086/527535 0708.4037

    ADS  Google Scholar 

  • Ptak A, Yaqoob T, Serlemitsos PJ, Mushotzky R, Otani C (1994) Rapid X-ray spectral variability in NGC 3227. Astrophys J Lett 436: L31–L34. doi:10.1086/187626

    ADS  Google Scholar 

  • Puccetti S, Risaliti G, Fiore F, Elvis M, Nicastro F, Perola GC, Capalbi M (2004) Rapid N H changes in NGC 4151. Nucl Phys B Proc Suppl 132: 225–228. doi:10.1016/j.nuclphysbps.2004.04.039 arXiv:astro-ph/0311446

    ADS  Google Scholar 

  • Rees MJ (1977) George DARWIN Lecture 1976—Quasars and young galaxies. Quart J RAS 18: 429–442

    ADS  Google Scholar 

  • Reeves J, Done C, Pounds K, Terashima Y, Hayashida K, Anabuki N, Uchino M, Turner M (2008) On why the iron K-shell absorption in AGN is not a signature of the local warm/hot intergalactic medium. Mon Not RAS 385: L108–L112. doi:10.1111/j.1745-3933.2008.00443.x 0801.1587

    ADS  Google Scholar 

  • Reeves JN, Wynn G, O’Brien PT, Pounds KA (2002) Extreme X-ray variability in the luminous quasar PDS 456. Mon Not RAS 336: L56–L60. doi:10.1046/j.1365-8711.2002.06038.x arXiv:astro-ph/0209120

    ADS  Google Scholar 

  • Reeves JN, O’Brien PT, Ward MJ (2003) A massive X-ray outflow from the quasar PDS 456. Astrophys J Lett 593: L65–L68. doi:10.1086/378218 arXiv:astro-ph/0307127

    ADS  Google Scholar 

  • Reeves JN, Nandra K, George IM, Pounds KA, Turner TJ, Yaqoob T (2004) The XMM-Newton iron line profile of NGC 3783. Astrophys J 602: 648–658. doi:10.1086/381091 arXiv:astro-ph/0310820

    ADS  Google Scholar 

  • Reeves JN, Awaki H, Dewangan GC, Fabian AC, Fukazawa Y, Gallo L, Griffiths R, Inoue H, Kunieda H, Markowitz A, Miniutti G, Mizuno T, Mushotzky R, Okajima T, Ptak A, Takahashi T, Terashima Y, Ushio M, Watanabe S, Yamasaki T, Yamauchi M, Yaqoob T (2007) Revealing the high energy emission from the obscured Seyfert galaxy MCG-5-23-16 with Suzaku. Publ ASJ 59: 301–314 arXiv:astro-ph/0610434

    ADS  Google Scholar 

  • Reichert GA, Mushotzky RF, Holt SS, Petre R (1985) Soft X-ray spectral observations of low-luminosity active galaxies. Astrophys J 296: 69–89. doi:10.1086/163421

    ADS  Google Scholar 

  • Reynolds CS (1997) An X-ray spectral study of 24 type 1 active galactic nuclei. Mon Not RAS 286: 513–537 arXiv:astro-ph/9610127

    ADS  Google Scholar 

  • Reynolds CS, Fabian AC (1997) Special relativistic effects on the strength of the fluorescent Kalpha iron line from black hole accretion discs. Mon Not RAS 290: L1–L5 arXiv:astro-ph/9707082

    ADS  Google Scholar 

  • Reynolds CS, Nowak MA (2003) Fluorescent iron lines as a probe of astrophysical black hole systems. Phys Rep 377: 389–466 arXiv:astro-ph/0212065

    ADS  Google Scholar 

  • Reynolds CS, Wilms J (2000) On the inability of comptonization to produce the broad X-ray iron lines observed in Seyfert nuclei. Astrophys J 533: 821–825. doi:10.1086/308712 arXiv:astro-ph/9912120

    ADS  Google Scholar 

  • Reynolds CS, Fabian AC, Inoue H (1995) ASCA observations of the Seyfert 1 galaxies MRK 1040 and MS 0225.5+3121. Mon Not RAS 276: 1311–1319 arXiv:astro-ph/9504095

    ADS  Google Scholar 

  • Reynolds CS, Wilms J, Begelman MC, Staubert R, Kendziorra E (2004) On the deep minimum state in the Seyfert galaxy MCG-6-30-15. Mon Not RAS 349: 1153–1166. doi:10.1111/j.1365-2966.2004.07596.x arXiv:astro-ph/0401305

    ADS  Google Scholar 

  • Richards GT, Vanden Berk DE, Reichard TA, Hall PB, Schneider DP, SubbaRao M, Thakar AR, York DG (2002) Broad emission-line shifts in quasars: an orientation measure for radio-quiet quasars?. Astron J 124: 1–17. doi:10.1086/341167 arXiv:astro-ph/0204162

    ADS  Google Scholar 

  • Risaliti G, Bianchi S, Matt G, Baldi A, Elvis M, Fabbiano G, Zezas A (2005) Highly ionized iron absorption lines from outflowing gas in the X-ray spectrum of NGC 1365. Astrophys J Lett 630: L129–L132. doi:10.1086/491646 arXiv:astro-ph/0508608

    ADS  Google Scholar 

  • Risaliti G, Elvis M, Fabbiano G, Baldi A, Zezas A, Salvati M (2007) Occultation measurement of the size of the X-ray-emitting region in the active galactic nucleus of NGC 1365. Astrophys J Lett 659: L111–L114. doi:10.1086/517884 arXiv:astro-ph/0703173

    ADS  Google Scholar 

  • Ross RR, Fabian AC (2005) A comprehensive range of X-ray ionized-reflection models. Mon Not RAS 358: 211–216. doi:10.1111/j.1365-2966.2005.08797.x arXiv:astro-ph/0501116

    ADS  Google Scholar 

  • Ross RR, Fabian AC, Young AJ (1999) X-ray reflection spectra from ionized slabs. Mon Not RAS 306: 461–466 arXiv:astro-ph/9902325

    ADS  Google Scholar 

  • Sako M, Kahn SM, Behar E, Kaastra JS, Brinkman AC, Boller T, Puchnarewicz EM, Starling R, Liedahl DA, Clavel J, Santos-Lleo M (2001) Complex resonance absorption structure in the X-ray spectrum of IRAS 13349+2438. Astron Astrophys 365: L168–L173. doi:10.1051/0004-6361:20000081 arXiv:astro-ph/0010660

    ADS  Google Scholar 

  • Schurch NJ, Done C (2007) The impact of accretion disc winds on the X-ray spectrum of AGN. I. XSCORT. Mon Not RAS 381: 1413–1425. doi:10.1111/j.1365-2966.2007.12336.x 0706.1885

    ADS  Google Scholar 

  • Schurch NJ, Done C (2008) Funnel wall jets and the nature of the soft X-ray excess. Mon Not RAS 386: L1–L4. doi:10.1111/j.1745-3933.2007.00395.x 0709.2650

    ADS  Google Scholar 

  • Schurch NJ, Done C, Proga D (2008) The impact of accretion disk winds on the X-ray spectrum of AGN. Part 2. XSCORT + Hydrodynamic Simulations. ArXiv e-prints 0810.0884

  • Shakura NI, Syunyaev RA (1973) Black holes in binary systems. Observational appearance. Astron Astrophys 24: 337–355

    ADS  Google Scholar 

  • Sim SA, Long KS, Miller L, Turner TJ (2008) Multidimensional modelling of X-ray spectra for AGN accretion disc outflows. Mon Not RAS 388: 611–624. doi:10.1111/j.1365-2966.2008.13466.x 0805.2251

    ADS  Google Scholar 

  • Smith RAN, Page MJ, Branduardi-Raymont G (2007) The XMM-Newton RGS spectrum of the high luminosity Seyfert 1 galaxy Markarian 509. Astron Astrophys 461: 135–142. doi:10.1051/0004-6361:20065348 arXiv:astro-ph/0609746

    ADS  Google Scholar 

  • Sobolewska MA, Done C (2007) What is the origin of the soft excess in active galactic nuclei?. Mon Not RAS 374: 150–158. doi:10.1111/j.1365-2966.2006.11117.x arXiv:astro-ph/0609223

    ADS  Google Scholar 

  • Soltan A (1982) Masses of quasars. Mon Not RAS 200: 115–122

    ADS  Google Scholar 

  • Steenbrugge KC, Kaastra JS, Crenshaw DM, Kraemer SB, Arav N, George IM, Liedahl DA, van der Meer RLJ, Paerels FBS, Turner TJ, Yaqoob T (2005) Simultaneous X-ray and UV spectroscopy of the Seyfert galaxy NGC 5548. II. Physical conditions in the X-ray absorber. Astron Astrophys 434: 569–584. doi:10.1051/0004-6361:20047138 arXiv:astro-ph/0501122

    ADS  Google Scholar 

  • Sulentic JW, Marziani P, Zwitter T, Calvani M, Dultzin-Hacyan D (1998) On the origin of broad Fe K alpha and H i H alpha lines in active galactic nuclei. Astrophys J 501: 54–68. doi:10.1086/305795 arXiv:astro-ph/9712336

    ADS  Google Scholar 

  • Takahashi T, Abe K, Endo M, Endo Y, Ezoe Y, Fukazawa Y, Hamaya M, Hirakuri S, Hong S, Horii M, Inoue H, Isobe N, Itoh T, Iyomoto N, Kamae T, Kasama D, Kataoka J, Kato H, Kawaharada M, Kawano N, Kawashima K, Kawasoe S, Kishishita T, Kitaguchi T, Kobayashi Y, Kokubun M, Kotoku J, Kouda M, Kubota A, Kuroda Y, Madejski G, Makishima K, Masukawa K, Matsumoto Y, Mitani T, Miyawaki R, Mizuno T, Mori K, Mori M, Murashima M, Murakami T, Nakazawa K, Niko H, Nomachi M, Okada Y, Ohno M, Oonuki K, Ota N, Ozawa H, Sato G, Shinoda S, Sugiho M, Suzuki M, Taguchi K, Takahashi H, Takahashi I, Takeda S, Tamura KI, Tamura T, Tanaka T, Tanihata C, Tashiro M, Terada Y, Tominaga S, Uchiyama Y, Watanabe S, Yamaoka K, Yanagida T, Yonetoku D (2007) Hard X-ray detector (HXD) on Board Suzaku. Publ ASJ 59: 35–51 arXiv:astro-ph/0611232

    Google Scholar 

  • Tanaka Y, Inoue H, Holt SS (1994) The X-ray astronomy satellite ASCA. Publ ASJ 46: L37–L41

    ADS  Google Scholar 

  • Tanaka Y, Nandra K, Fabian AC, Inoue H, Otani C, Dotani T, Hayashida K, Iwasawa K, Kii T, Kunieda H, Makino F, Matsuoka M (1995) Gravitationally redshifted emission implying an accretion disk and massive black-hole in the active galaxy MCG-6-30-15. Nature 375: 659–661. doi:10.1038/375659a0

    ADS  Google Scholar 

  • Tarter CB, Tucker WH, Salpeter EE (1969) The interaction of X-ray sources with optically thin environments. Astrophys J 156: 943–951

    ADS  Google Scholar 

  • Terashima Y, Gallo LC, Inoue H, Markowitz AG, Reeves JN, Anabuki N, Fabian AC, Griffiths RE, Hayashida K, Itoh T, Kokubun N, Kubota A, Miniutti G, Takahashi T, Yamauchi M, Yonetoku D (2008) X-ray spectral variability of the Seyfert galaxy NGC 4051 observed with Suzaku. ArXiv e-prints 0811.0692

  • Titarchuk L, Kazanas D, Becker PA (2003) Broad redshifted line as a signature of outflow. Astrophys J 598: 411–418. doi:10.1086/378701 arXiv:astro-ph/0307486

    ADS  Google Scholar 

  • Titarchuk LG, Hua XM (1997) Comptonization models and spectroscopy of X-ray and gamma-ray sources. Adv Space Res 19: 99–108. doi:10.1016/S0273-1177(97)00043-4

    ADS  Google Scholar 

  • Tremaine S, Gebhardt K, Bender R, Bower G, Dressler A, Faber SM, Filippenko AV, Green R, Grillmair C, Ho LC, Kormendy J, Lauer TR, Magorrian J, Pinkney J, Richstone D (2002) The slope of the black hole mass versus velocity dispersion correlation. Astrophys J 574: 740–753. doi:10.1086/341002 arXiv:astro-ph/0203468

    ADS  Google Scholar 

  • Tucker W, Kellogg E, Gursky H, Giacconi R, Tananbaun H (1973) X-ray observations of NGC 5128 (centaurus a) from UHURU. Astrophys J 180: 715–724

    ADS  Google Scholar 

  • Tueller J, Mushotzky RF, Barthelmy S, Cannizzo JK, Gehrels N, Markwardt CB, Skinner GK, Winter LM (2008) Swift BAT survey of AGNs. Astrophys J 681: 113–127. doi:10.1086/588458 0711.4130

    ADS  Google Scholar 

  • Turner AK, Fabian AC, Vaughan S, Lee JC (2003) A softer look at MCG-6-30-15 with XMM-Newton. Mon Not RAS 346: 833–840. doi:10.1111/j.1365-2966.2003.07127.x arXiv:astro-ph/0303418

    ADS  Google Scholar 

  • Turner AK, Fabian AC, Lee JC, Vaughan S (2004a) The soft X-ray absorption lines of the Seyfert 1 galaxy MCG-6-30-15. Mon Not RAS 353: 319–328. doi:10.1111/j.1365-2966.2004.08075.x arXiv:astro-ph/0405570

    ADS  Google Scholar 

  • Turner TJ, Pounds KA (1988) Variability of the soft excess in the Seyfert I galaxy MKN 335. Mon Not RAS 232: 463–471

    ADS  Google Scholar 

  • Turner TJ, Pounds KA (1989) The EXOSAT spectral survey of AGN. Mon Not RAS 240: 833–880

    ADS  Google Scholar 

  • Turner TJ, George IM, Mushotzky RF (1993a) ROSAT position sensitive proportional counter spectra of six Seyfert 1 galaxies. Astrophys J 412: 72–81. doi:10.1086/172901

    ADS  Google Scholar 

  • Turner TJ, Nandra K, George IM, Fabian AC, Pounds KA (1993b) X-ray observations of the warm absorber in NGC 3783. Astrophys J 419: 127–135. doi:10.1086/173466

    ADS  Google Scholar 

  • Turner TJ, George IM, Nandra K, Mushotzky RF (1997) ASCA observations of type 2 Seyfert Galaxies. I. Data analysis results. Astrophys J Suppl 113: 23–67. doi:10.1086/313053

    ADS  Google Scholar 

  • Turner TJ, George IM, Nandra K, Turcan D (1999) On X-ray variability in Seyfert galaxies. Astrophys J 524: 667–673. doi:10.1086/307834 arXiv:astro-ph/9906050

    ADS  Google Scholar 

  • Turner TJ, Mushotzky RF, Yaqoob T, George IM, Snowden SL, Netzer H, Kraemer SB, Nandra K, Chelouche D (2002) Narrow components within the Fe Kα profile of NGC 3516: evidence of the importance of general relativistic effects?. Astrophys J Lett 574: L123–L127. doi:10.1086/342504 arXiv:astro-ph/0206223

    ADS  Google Scholar 

  • Turner TJ, Kraemer SB, Reeves JN (2004b) Transient relativistically shifted lines as a probe of black hole systems. Astrophys J 603: 62–66. doi:10.1086/381312 arXiv:astro-ph/0310885

    ADS  Google Scholar 

  • Turner TJ, Kraemer SB, George IM, Reeves JN, Bottorff MC (2005) Complex X-Ray Absorption and the Fe Kα profile in NGC 3516. Astrophys J 618: 155–166. doi:10.1086/425961 arXiv:astro-ph/0409091

    ADS  Google Scholar 

  • Turner TJ, Miller L, George IM, Reeves JN (2006) Evidence for orbital motion of material close to the central black hole of Mrk 766. Astron Astrophys 445: 59–67. doi:10.1051/0004-6361:20053042 arXiv:astro-ph/0506223

    ADS  Google Scholar 

  • Turner TJ, Miller L, Reeves JN, Kraemer SB (2007) The variable X-ray spectrum of Markarian 766. II. Time-resolved spectroscopy. Astron Astrophys 475: 121–131. doi:10.1051/0004-6361:20077947 0708.1338

    ADS  Google Scholar 

  • Turner TJ, Reeves JN, Kraemer SB, Miller L (2008) Tracing a disk wind in NGC 3516. Astron Astrophys 483: 161–169. doi:10.1051/0004-6361:20078808 0803.0080

    ADS  Google Scholar 

  • Urry CM, Padovani P (1995) Unified schemes for radio-loud active galactic nuclei. Publ ASP 107: 803–845 arXiv:astro-ph/9506063

    ADS  Google Scholar 

  • Vaughan S, Fabian AC (2004) A long hard look at MCG-6-30-15 with XMM-Newton- II. Detailed EPIC analysis and modelling. Mon Not RAS 348: 1415–1438. doi:10.1111/j.1365-2966.2004.07456.x arXiv:astro-ph/0311473

    Google Scholar 

  • Vaughan S, Uttley P (2008) On the evidence for narrow, relativistically shifted X-ray lines. ArXiv e-prints 0807.4806

  • Walter R, Fink HH (1993) The Ultraviolet to Soft X-ray bump of SEYFERT-1 type active galactic nuclei. Astron Astrophys 274: 105–122

    ADS  Google Scholar 

  • Wandel A (2002) Black Holes of Active and Quiescent Galaxies. I. The Black Hole-Bulge Relation Revisited. Astrophysical Journal 565: 762–772. doi:10.1086/338134 arXiv:astro-ph/0108461

    ADS  Google Scholar 

  • Wandel A, Peterson BM, Malkan MA (1999) Central masses and broad-line region sizes of active galactic nuclei. I. Comparing the photoionization and reverberation techniques. Astrophy J 526: 579–591. doi:10.1086/308017 arXiv:astro-ph/9905224

    ADS  Google Scholar 

  • Wang JM, Qu JL, Xue SJ (2004) The additional line component within the iron Kα profile in MCG-6-30-15: evidence for blob ejection?. Astrophys J 609: 107–112. doi:10.1086/420892 arXiv:astro-ph/0407124

    ADS  Google Scholar 

  • Ward M, Elvis M, Fabbiano G, Carleton NP, Willner SP, Lawrence A (1987) The continuum of type 1 Seyfert galaxies. I. A single form modified by the effects of dust. Astrophys J 315: 74–91. doi:10.1086/165115

    ADS  Google Scholar 

  • Warwick RS, Pounds KA, Turner TJ (1988) Variable low-energy absorption in the X-ray spectrum of ESO 103-G35. Mon Not RAS 231: 1145–1152

    ADS  Google Scholar 

  • Weaver KA, Mushotzky RF, Arnaud KA, Serlemitsos PJ, Marshall FE, Petre R, Jahoda KM, Smale AP, Netzer H (1994) The complex soft X-ray excess in NGC 4151. Astrophys J 423: 621–632. doi:10.1086/173840

    ADS  Google Scholar 

  • Weymann RJ, Morris SL, Foltz CB, Hewett PC (1991) Comparisons of the emission-line and continuum properties of broad absorption line and normal quasi-stellar objects. Astrophys J 373: 23–53. doi:10.1086/170020

    ADS  Google Scholar 

  • Wilkes BJ, Elvis M (1987) Quasar energy distributions. I. Soft X-ray spectra of quasars. Astrophys J 323: 243–262. doi:10.1086/165822

    ADS  Google Scholar 

  • Wilms J, Reynolds CS, Begelman MC, Reeves J, Molendi S, Staubert R, Kendziorra E (2001) XMM-EPIC observation of MCG-6-30-15: direct evidence for the extraction of energy from a spinning black hole?. Mon Not RAS 328: L27–L31. doi:10.1046/j.1365-8711.2001.05066.x arXiv:astro-ph/0110520

    ADS  Google Scholar 

  • Woo JH, Urry CM (2002) Active galactic nucleus black hole masses and bolometric luminosities. Astrophys J 579: 530–544. doi:10.1086/342878 arXiv:astro-ph/0207249

    ADS  Google Scholar 

  • Wu XB, Liu FK (2004) Black Hole mass and accretion rate of active galactic nuclei with double-peaked broad emission lines. Astrophys J 614: 91–100. doi:10.1086/423446 arXiv:astro-ph/0406415

    ADS  Google Scholar 

  • Yaqoob T, Padmanabhan U (2004) The cores of the Fe K lines in seyfert 1 galaxies observed by the Chandra high energy grating. Astrophys J 604: 63–73. doi:10.1086/381731 arXiv:astro-ph/0311551

    ADS  Google Scholar 

  • Yaqoob T, Serlemitsos P (2005) Iron K features in the quasar E1821+643: evidence for gravitationally redshifted absorption. Astrophys J 623: 112–122. doi:10.1086/428432 arXiv:astro-ph/0502128

    ADS  Google Scholar 

  • Yaqoob T, Warwick RS, Pounds KA (1989) Variable X-ray absorption in NGC 4151. Mon Not RAS 236: 153–170

    ADS  Google Scholar 

  • Yaqoob T, Serlemitsos P, Mushotzky R, Madejski G, Turner TJ, Kunieda H (1994) X-ray spectrum and variability of the quasar PG 1211+143. Publ ASJ 46: L173–L177

    ADS  Google Scholar 

  • Yaqoob T, George IM, Nandra K, Turner TJ, Serlemitsos PJ, Mushotzky RF (2001) Physical diagnostics from a narrow Fe Kα emission line detected by Chandra in the Seyfert 1 galaxy NGC 5548. Astrophys J 546: 759–768. doi:10.1086/318315 arXiv:astro-ph/0008471

    ADS  Google Scholar 

  • Yaqoob T, George IM, Kallman TR, Padmanabhan U, Weaver KA, Turner TJ (2003) Fe XXV and Fe XXVI diagnostics of the black hole and accretion disk in active galaxies: Chandra time-resolved grating spectroscopy of NGC 7314. Astrophys J 596: 85–104. doi:10.1086/377687 arXiv:astro-ph/0306428

    ADS  Google Scholar 

  • Young AJ, Lee JC, Fabian AC, Reynolds CS, Gibson RR, Canizares CR (2005) A Chandra HETGS spectral study of the iron K bandpass in MCG-6-30-15: a narrow view of the broad iron line. Astrophys J 631: 733–740. doi:10.1086/432607 arXiv:astro-ph/0506082

    ADS  Google Scholar 

  • Yu Q, Tremaine S (2002) Observational constraints on growth of massive black holes. Mon Not RAS 335: 965–976. doi:10.1046/j.1365-8711.2002.05532.x arXiv:astro-ph/0203082

    ADS  Google Scholar 

  • Zamorani G, Henry JP, Maccacaro T, Tananbaum H, Soltan A, Avni Y, Liebert J, Stocke J, Strittmatter PA, Weymann RJ, Smith MG, Condon JJ (1981) X-ray studies of quasars with the Einstein Observatory II. Astrophys J 245: 357–374. doi:10.1086/158815

    ADS  Google Scholar 

  • Zdziarski AA, Fabian AC, Nandra K, Celotti A, Rees MJ, Done C, Coppi PS, Madejski GM (1994) Physical processes in the X-ray/gamma-ray source of IC4329A. Mon Not RAS 269: L55–L60

    ADS  Google Scholar 

  • Życki PT (2004) Modelling the variability of the Fe Kα line in accreting black holes. Mon Not RAS 351: 1180–1186. doi:10.1111/j.1365-2966.2004.07852.x arXiv:astro-ph/0403442

    ADS  Google Scholar 

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Turner, T.J., Miller, L. X-ray absorption and reflection in active galactic nuclei. Astron Astrophys Rev 17, 47–104 (2009). https://doi.org/10.1007/s00159-009-0017-1

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