The power output of local obscured and unobscured AGN: crossing the absorption barrier with Swift/ BAT and IRAS

The Swift/Burst Alert Telescope (BAT) 9-month catalogue of active galactic nuclei (AGN) provides an unbiased census of local supermassive black hole accretion, and probes to all but the highest levels of absorption in AGN. We explore a method for characterizing the bolometric output of both obscured and unobscured AGN by combining the hard X-ray data from the Swift/BAT instrument (14-195keV) with the reprocessed infrared (IR) emission as seen with the Infrared Astronomical Satellite (IRAS) all-sky surveys. This approach bypasses the complex modifications to the spectral energy distribution introduced by absorption in the optical, UV and 0.1-10 keV regimes and provides a long-term, average picture of the bolometric output of these sources. We broadly follow the approach of Pozzi et al. for calculating the bolometric luminosities by adding nuclear IR and hard X-ray luminosities, and consider different approaches for removing non-nuclear contamination in the large-aperture IRAS fluxes. Using mass estimates from the black hole mass-host galaxy bulge luminosity relation, we present the Eddington ratios λ Edd and 2-10 keV bolometric corrections for a subsample of 63 AGN (35 obscured and 28 unobscured) from the Swift/BAT catalogue, and confirm previous indications of a low Eddington ratio distribution for both samples. Importantly, we find a tendency for low bolometric corrections (typically 10-30) for the obscured AGN in the sample (with a possible rise from ∼15 for λ Edd < 0.03 to ∼32 above this), providing a hitherto unseen window on to accretion processes in this class of AGN. This finding is of key importance in calculating the expected local black hole mass density from the X-ray background since it is composed of emission from a significant population of such obscured AGN. Analogous studies with high-resolution IR data and a range of alternative models for the torus emission will form useful future extensions to this work.

[1]  A. Fabian,et al.  Optical-to-X-ray emission in low-absorption AGN: results from the Swift–BAT 9-month catalogue , 2009, 0907.2272.

[2]  B. Skiff,et al.  VizieR Online Data Catalog , 2009 .

[3]  J. M. Rodríguez Espinosa,et al.  THE INFRARED NUCLEAR EMISSION OF SEYFERT GALAXIES ON PARSEC SCALES: TESTING THE CLUMPY TORUS MODELS , 2009, Proceedings of the International Astronomical Union.

[4]  K. Nandra,et al.  AGN dust tori: the X-ray-infrared connection , 2009, 0905.4389.

[5]  S. Bianchi,et al.  The bolometric luminosity of type 2 AGN from extinction-corrected [OIII]. No evidence of Eddington-l , 2009, 0905.4439.

[6]  S. Uddin,et al.  DUST EMISSION FROM UNOBSCURED ACTIVE GALACTIC NUCLEI , 2009, 0903.2422.

[7]  W. Duschl,et al.  Resolving the mid-infrared cores of local Seyferts , 2009, 0902.2777.

[8]  S. Bianchi,et al.  VARIABLE PARTIAL COVERING AND A RELATIVISTIC IRON LINE IN NGC 1365 , 2009, 0901.4809.

[9]  B. McKernan,et al.  Frying doughnuts: what can the reprocessing of X‐rays to IR tell us about the AGN environment? , 2008, 0812.0984.

[10]  A. Fabian,et al.  Simultaneous X-ray/optical/UV snapshots of active galactic nuclei from XMM–Newton: spectral energy distributions for the reverberation mapped sample , 2008, 0810.3777.

[11]  Y. Terashima,et al.  STUDY ON X-RAY SPECTRA OF OBSCURED ACTIVE GALACTIC NUCLEI BASED ON MONTE CARLO SIMULATION—AN INTERPRETATION OF OBSERVED WIDE-BAND SPECTRA , 2008, 0810.3950.

[12]  H. Schmitt,et al.  Constraining the Active Galactic Nucleus Contribution in a Multiwavelength Study of Seyfert Galaxies , 2008, 0808.4154.

[13]  L. Winter,et al.  X-RAY SPECTRAL PROPERTIES OF THE BAT AGN SAMPLE , 2008, 0808.0461.

[14]  G. Weigelt,et al.  Probing the dusty environment of the Seyfert 1 nucleus in NGC 3783 with MIDI/VLTI interferometry , 2008, 0806.0531.

[15]  Ž. Ivezić,et al.  AGN Dusty Tori. II. Observational Implications of Clumpiness , 2008, 0806.0512.

[16]  Zeljko Ivezic,et al.  AGN Dusty Tori. I. Handling of Clumpy Media , 2008, 0806.0511.

[17]  Alain Smette,et al.  The mid IR - hard X-ray correlation in AGN and its implications for dusty torus models , , 2007, 0711.3734.

[18]  S. Barthelmy,et al.  Swift BAT Survey of AGNs , 2007, 0711.4130.

[19]  M. J. Page,et al.  The XMM large scale structure survey: Optical vs. X-ray classifications of active galactic nuclei and the unified scheme , 2007, 0709.2077.

[20]  Observatoire de la Cote d'Azur,et al.  Resolving the complex structure of the dust torus in the active nucleus of the Circinus galaxy , 2007, 0709.0209.

[21]  A. Fabian,et al.  Piecing together the X-ray background : bolometric corrections for active galactic nuclei , 2007, 0708.4308.

[22]  A. Markowitz,et al.  Wide-Band Spectroscopy of the Compton Thick Seyfert2 Galaxy Markarian 3 with Suzaku , 2007, 0707.2425.

[23]  菅沼 正洋,et al.  日本天文学会 早川幸男基金による渡航報告書 : The Central Engine of Active Galactic Nuclei , 2007 .

[24]  G. Zamorani,et al.  The HELLAS2XMM survey X. The bolometric output of luminous obscured quasars: The Spitzer perspective , 2007, 0704.0735.

[25]  A. Comastri,et al.  The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era , 2006, astro-ph/0610939.

[26]  A. Markowitz,et al.  Suzaku Observations of the Hard X-ray Variability of MCG-6-30-15: the Effects of Strong Gravity Around a Kerr Black Hole , 2006, astro-ph/0609521.

[27]  W. Duschl,et al.  The small dispersion of the mid IR - hard X-ray correlation in active galactic nuclei , 2006, astro-ph/0608358.

[28]  Dimitra Rigopoulou,et al.  Infrared Power-Law Galaxies in the Chandra Deep Field-South: Active Galactic Nuclei and Ultraluminous Infrared Galaxies , 2006 .

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

[30]  G. Weigelt,et al.  Radiative transfer modeling of three-dimensional clumpy AGN tori and its application to NGC 1068 , 2006, astro-ph/0602494.

[31]  A. Streblyanska,et al.  XMM-Newton observations of the Lockman Hole IV: spectra of the brightest AGN , , 2005, astro-ph/0506718.

[32]  J. Silverman,et al.  Hard X-Ray-emitting Active Galactic Nuclei Selected by the Chandra Multiwavelength Project , 2004, astro-ph/0409337.

[33]  A. Barger.  Supermassive Black Holes in the Distant Universe , 2004 .

[34]  R. Mushotzky.  How are AGN Found , 2004, astro-ph/0405144.

[35]  M. Schoeller,et al.  The central dusty torus in the active nucleus of NGC 1068 , 2004, Nature.

[36]  Italy.,et al.  Connecting the cosmic infrared background to the X-ray background , 2004, astro-ph/0403381.

[37]  R. Della Ceca,et al.  Coevolution of Black Holes and Galaxies , 2004 .

[38]  Silvano Molendi,et al.  The HELLAS2XMM 1dF Survey: On the Nature of High X-Ray/Optical Flux Sources , 2004 .

[39]  P. Martini,et al.  Coevolution of Black Holes and Galaxies , 2004 .

[40]  A. Marconi,et al.  The Relation between Black Hole Mass, Bulge Mass, and Near-Infrared Luminosity , 2003, astro-ph/0304274.

[41]  A. Marconi,et al.  Spectroscopy of the near-nuclear regions of Cygnus A: estimating the mass of the supermassive black hole , 2003, astro-ph/0302513.

[42]  A. C. Fabian,et al.  X-ray background synthesis: the infrared connection , 2002, astro-ph/0211129.

[43]  J. C. Lee,et al.  A long hard look at MCG–6-30-15 with XMM-Newton , 2002, astro-ph/0311473.

[44]  M. S. Oey,et al.  Atlas of quasar energy distributions , 1994 .

[45]  L. Danese,et al.  Thick tori around active galactic nuclei: a comparison of model predictions with observations of the infrared continuum and silicate features , 1994 .

[46]  Hideyo Kunieda,et al.  X-Ray Evidence for Seyfert Activity Buried in the Infrared Galaxy NGC 4945 , 1993 .

[47]  Robert Antonucci,et al.  Unified models for active galactic nuclei and quasars , 1993 .

[48]  Julian H. Krolik,et al.  Infrared spectra of obscuring dust tori around active galactic nuclei. I - Calculational method and basic trends , 1992 .

[49]  A. Fabian,et al.  Electron-positron pairs, Compton reflection, and the X-ray spectra of active galactic nuclei , 1990 .

[50]  M. Malkan,et al.  Fitting improved accretion disk models to the multiwavelength continua of quasars and active galactic nuclei , 1989 .

[51]  R. Barvainis,et al.  Hot Dust and the Near-Infrared Bump in the Continuum Spectra of Quasars and Active Galactic Nuclei , 1987 .

[52]  Andrzej Soƚtan,et al.  Masses of quasars , 1982 .

[53]  G. Shields.  Thermal continuum from accretion disks in quasars , 1978, Nature.