Bolometric luminosities and Eddington ratios of X-ray selected active galactic nuclei in the XMM-COSMOS survey

E. Lusso, A. Comastri, B. D. Simmons, M. Mignoli, G. Zamorani, C. Vignali, M. Brusa, F. Shankar, D. Lutz, J. R. Trump, R. Maiolino, R. Gilli, M. Bolzonella, S. Puccetti, M. Salvato, C. D. Impey, F. Civano, M. Elvis, V. Mainieri, J. D. SilvermanA. M. Koekemoer, A. Bongiorno, A. Merloni, S. Berta, E. Le Floc'h, B. Magnelli, F. Pozzi, L. Riguccini

Research output: Contribution to journalArticlepeer-review

319 Scopus citations

Abstract

Bolometric luminosities and Eddington ratios of both X-ray selected broad-line (Type-1) and narrow-line (Type-2) active galactic nuclei (AGN) from the XMM-Newton survey in the Cosmic Evolution Survey field are presented. The sample is composed of 929 AGN (382 Type-1 AGN and 547 Type-2 AGN) and it covers a wide range of redshifts, X-ray luminosities and absorbing column densities. About 65per cent of the sources are spectroscopically identified as either Type-1 or Type-2 AGN (83 and 52per cent, respectively), while accurate photometric redshifts are available for the rest of the sample. The study of such a large sample of X-ray selected AGN with a high-quality multiwavelength coverage from the far-infrared (now with the inclusion of Herschel data at 100 and 160 μm) to the optical-ultraviolet allows us to obtain accurate estimates of bolometric luminosities, bolometric corrections and Eddington ratios. The k bol - L bol relations derived in this work are calibrated for the first time against a sizable AGN sample, and rely on observed redshifts, X-ray luminosities and column density distributions. We find that k bol is significantly lower at high L bol with respect to previous estimates by Marconi et al. and Hopkins et al. Black hole (BH) masses and Eddington ratios are available for 170 Type-1 AGN, while BH masses for Type-2 AGN are computed for 481 objects using the BH mass-stellar mass relation and the morphological information. We confirm a trend between k bol and λ Edd, with lower hard X-ray bolometric corrections at lower Eddington ratios for both Type-1 and Type-2 AGN. We find that, on average, the Eddington ratio increases with redshift for all types of AGN at any given M BH, while no clear evolution with redshift is seen at any given L bol.

Original languageEnglish (US)
Pages (from-to)623-640
Number of pages18
JournalMonthly Notices of the Royal Astronomical Society
Volume425
Issue number1
DOIs
StatePublished - Sep 1 2012

Keywords

  • Galaxies: active
  • Galaxies: evolution
  • Methods: statistical
  • Quasars: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint Dive into the research topics of 'Bolometric luminosities and Eddington ratios of X-ray selected active galactic nuclei in the XMM-COSMOS survey'. Together they form a unique fingerprint.

Cite this