Radio and X-ray emission from disc winds in radio-quiet quasars

It has been proposed that the radio spectra of radio-quiet quasars are produced by free–free emission in the optically thin part of an accretion disc wind. An important observational constraint on this model is the observed X-ray luminosity. We investigate this constraint using a sample of Palomar–Green (PG) radio-quiet quasars for which XMM–Newton European Photon Imaging Camera (EPIC) spectra are available. Comparing the predicted and measured luminosities for 0.5, 2 and 5 keV, we conclude that all of the studied PG quasars require a large hydrogen column density absorber, requiring these quasars to be close to or Compton thick. Such a large column density can be directly excluded for PG 0050+124, for which a highresolution reflection grating spectrometer spectrum exists. Further constraint on the column density for a further 19 out of the 21 studied PG quasars comes from the EPIC spectrum characteristics such as hard X-ray power-law photon index and the equivalent width of the Fe Kα line; and the small equivalent width of the C IV absorber present in ultraviolet spectra. For two sources, PG 1001+054 and PG 1411+442, we cannot exclude that they are indeed Compton thick, and the radio and X-ray luminosity are due to a wind originating close to the supermassive black hole. We conclude that for 20 out of 22 PG quasars studied, free–free emission from a wind emanating from the accretion disc cannot mutually explain the observed radio and X-ray luminosity.

[1]  Psu,et al.  The quasar PG 0844+349 in an X-ray weak state , 2010, 1010.4453.

[2]  K. Korista,et al.  XMM-Newton RGS observation of the warm absorber in Mrk 279 , 2010, 1006.2027.

[3]  E. Behar.  DENSITY PROFILES IN SEYFERT OUTFLOWS , 2009, 0908.0539.

[4]  A. Fabian,et al.  Radio constraints on the volume filling factors of AGN winds , 2009, 0904.0209.

[5]  J. Kaastra,et al.  High-resolution X-ray spectroscopy of the low and high states of the Seyfert 1 galaxy NGC 4051 with Chandra LETGS , 2009, 0901.3108.

[6]  T. Dwelly,et al.  Properties of X‐ray‐selected broad absorption‐line quasars★ , 2008, 0808.2414.

[7]  A. Laor,et al.  On the origin of radio emission in radio-quiet quasars , 2008, 0808.0637.

[8]  K. Blundell,et al.  On the Origin of Radio Core Emission in Radio-quiet Quasars , 2007, 0708.2929.

[9]  S. Kaspi,et al.  Absorption Measure Distribution of the Outflow in IRAS 13349+2438: Direct Observation of Thermal Instability? , 2007, astro-ph/0703351.

[10]  Psu,et al.  A longer XMM–Newton look at I Zwicky 1: physical conditions and variability of the ionized absorbers , 2007, astro-ph/0702553.

[11]  N. Murray,et al.  Large-Scale Parker Winds in Active Galactic Nuclei , 2006, astro-ph/0610757.

[12]  Technion,et al.  X-ray/ultraviolet observing campaign of the Markarian 279 active galactic nucleus outflow : a close look at the absorbing/emitting gas with Chandra-LETGS , 2006, astro-ph/0609385.

[13]  R. Goosmann,et al.  Modeling the warm absorber in active galactic nuclei , 2006 .

[14]  D. Grupe,et al.  PG 0844+349 revisited - is there any outflow? , 2006 .

[15]  P. Schady,et al.  XMM-Newton Observations of the Laor et al. Sample of PG Quasars , 2006 .

[16]  H. Marshall,et al.  The High-Resolution X-Ray Spectrum of MR 2251–178 Obtained with the Chandra HETGS , 2005 .

[17]  D. Lemze,et al.  XMM-Newton Spectroscopy of the Starburst-Dominated Ultraluminous Infrared Galaxy NGC 6240 , 2005, astro-ph/0505016.

[18]  D. Chelouche.  Gravitational Microlensing and the Structure of Quasar Outflows , 2005, astro-ph/0504260.

[19]  N. Schartel,et al.  The XMM-Newton view of three X-ray weak quasars: Iron emission and strong ionized absorption , 2005 .

[20]  R. V. Meer,et al.  Simultaneous X-ray and UV spectroscopy of the Seyfert galaxy NGC 5548 - II. Physical conditions in the X-ray absorber , 2005, astro-ph/0501122.

[21]  R. Antonucci,et al.  VLBA Imaging of Central Engines in Radio-Quiet Quasars , 2004, astro-ph/0411678.

[22]  M. Page,et al.  The nature and origin of Seyfert warm absorbers , 2004, astro-ph/0411297.

[23]  N. Schartel,et al.  The XMM-Newton view of PG quasars - I. X-ray continuum and absorption , 2004, astro-ph/0411051.

[24]  J. Lehár,et al.  Radio Variability of Radio-quiet and Radio-loud Quasars , 2004, astro-ph/0409554.

[25]  K. Mason,et al.  XMM-Newton observations of warm absorbers in PG quasars , 2004, astro-ph/0408160.

[26]  Stsci,et al.  X-Ray/Ultraviolet Campaign on the Mrk 279 AGN Outflow: Constraining Inhomogeneous Absorber Models , 2004, astro-ph/0406200.

[27]  K. Nandra,et al.  The Properties and Evolution of the Highly Ionized Gas in MR 2251–178 , 2004, astro-ph/0404565.

[28]  N. Schartel,et al.  Evidence for a multizone warm absorber in the XMM–Newton spectrum of Markarian 304 , 2004, astro-ph/0404263.

[29]  D. Crenshaw,et al.  Mass Loss from the Nuclei of Active Galaxies , 2003 .

[30]  I. Papadakis,et al.  Combined long and short timescale X-ray variability of NGC 4051 with RXTE and XMM-Newton , 2003, astro-ph/0311220.

[31]  J. Kaastra,et al.  XMM-NEWTON High resolution spectroscopy of NGC 5548 , 2003, astro-ph/0302493.

[32]  Shai Kaspi,et al.  The Ionized Gas and Nuclear Environment in NGC 3783. II. Averaged Hubble Space Telescope/STIS and Far Ultraviolet Spectroscopic Explorer Spectra , 2003, astro-ph/0506323.

[33]  P. Hewett,et al.  The Frequency and Radio Properties of Broad Absorption Line Quasars , 2003, astro-ph/0301191.

[34]  R. V. Meer,et al.  X-ray spectroscopy of NGC 5548 , 2002, astro-ph/0202481.

[35]  et al,et al.  Optical and Radio Properties of Extragalactic Sources Observed by the FIRST Survey and the Sloan Digital Sky Survey , 2002, astro-ph/0202408.

[36]  P. Uttley,et al.  Measuring the broad-band power spectra of active galactic nuclei with RXTE , 2002, astro-ph/0201134.

[37]  Gerard A. Kriss,et al.  Warm Absorbers in Active Galactic Nuclei: A Multitemperature Wind , 2001 .

[38]  Shai Kaspi,et al.  High-Resolution X-Ray Spectroscopy and Modeling of the Absorbing and Emitting Outflow in NGC 3783 , 2001, astro-ph/0101540.

[39]  Boulder,et al.  Dynamics of Line-driven Disk Winds in Active Galactic Nuclei. II. Effects of Disk Radiation , 2000, astro-ph/0005315.

[40]  B. Wills,et al.  Hβ line width and the UV–X-ray spectra of luminous AGN , 2000, astro-ph/0005146.

[41]  M. Elvis.  A Structure for Quasars , 2000, astro-ph/0008064.

[42]  Z. Kuncic.  Broad Absorption Line Quasars and the Radio‐Loud/Radio‐Quiet Dichotomy , 1999, astro-ph/9905092.

[43]  G. Matt,et al.  X-ray spectra transmitted through Compton-thick absorbers , 1999, astro-ph/9904341.

[44]  J. Krolik.  Active Galactic Nuclei , 1998 .

[45]  K. Blundell,et al.  The central engines of radio-quiet quasars , 1998, astro-ph/9805169.

[46]  K. Nandra,et al.  ASCA Observations of Seyfert 1 Galaxies. III. The Evidence for Absorption and Emission Due to Photoionized Gas , 1997, astro-ph/9708046.

[47]  C. Reynolds,et al.  An X-ray spectral study of 24 type 1 active galactic nuclei , 1997 .

[48]  J. Chiang,et al.  Accretion Disk Winds from Active Galactic Nuclei , 1995 .

[49]  Maarten Schmidt,et al.  The radio structure of radio loud and radio quiet quasars in the Palomar Bright Quasar Survey , 1994 .

[50]  S. Rawlings,et al.  The radio and optical properties of the z<0.5 BQS quasars , 1993 .

[51]  T. Boroson,et al.  The Emission-Line Properties of Low-Redshift Quasi-stellar Objects , 1992 .

[52]  Simon L. Morris,et al.  Comparisons of the Emission-Line and Continuum Properties of Broad Absorption Line and Normal Quasi-stellar Objects , 1991 .

[53]  Maarten Schmidt,et al.  VLA observations of objects in the Palomar Bright Quasar Survey , 1989 .

[54]  F. Briggs,et al.  The broad absorption lines in the spectrum of the QSO PKS 1157+014 - A possible link between broad absorption line QSOs, metal enrichment, and the formation of galaxies , 1984 .

[55]  D. Osterbrock.  Active Galactic Nuclei a , 1984 .

[56]  Richard F. Green,et al.  Quasar evolution derived from the Palomar bright quasar survey and other complete quasar surveys. , 1983 .

[57]  J. J. Wittels,et al.  The very flat radio spectrum of 0735 plus 178 - A cosmic conspiracy , 1980 .

[58]  M. Voit,et al.  RADIATIVE PROCESSES , 2012 .

[59]  Dan McCammon,et al.  The Soft X-Ray Background and Its Origins , 1990 .

[60]  N. Grevesse,et al.  Abundances of the elements: Meteoritic and solar , 1989 .

[61]  G. Rybicki,et al.  Radiative processes in astrophysics , 1979 .

[62]  M. Barlow,et al.  The Radio and Infrared Spectrum of Early-type Stars Undergoing Mass Loss , 1975 .