The bolometric output and host-galaxy properties of obscured AGN in the XMM-COSMOS survey

  • E. Lusso
  • , A. Comastri
  • , C. Vignali
  • , G. Zamorani
  • , E. Treister
  • , D. Sanders
  • , M. Bolzonella
  • , A. Bongiorno
  • , M. Brusa
  • , F. Civano
  • , R. Gilli
  • , V. Mainieri
  • , P. Nair
  • , M. C. Aller
  • , M. Carollo
  • , A. M. Koekemoer
  • , A. Merloni
  • , J. R. Trump

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

We present a study of the multi-wavelength properties, from the mid-infrared to the hard X-rays, of a sample of 255 spectroscopically identified X-ray selected type-2 AGN from the XMM-COSMOS survey. Most of them are obscured and the X-ray absorbing column density is determined by either X-ray spectral analyses (for 45% of the sample), or from hardness ratios. Spectral energy distributions (SEDs) are computed for all sources in the sample. The average SEDs in the optical band are dominated by the host-galaxy light, especially at low X-ray luminosities and redshifts. There is also a trend between X-ray and mid-infrared luminosity: the AGN contribution in the infrared is higher at higher X-ray luminosities. We calculate bolometric luminosities, bolometric corrections, stellar masses and star formation rates (SFRs) for these sources using a multi-component modeling to properly disentangle the emission associated to stellar light from that due to black hole accretion. For 90% of the sample we also have the morphological classifications obtained with an upgraded version of the Zurich estimator of structural types (ZEST+). We find that on average type-2 AGN have lower bolometric corrections than type-1 AGN. Moreover, we confirm that the morphologies of AGN host-galaxies indicate that there is a preference for these type-2 AGN to be hosted in bulge-dominated galaxies with stellar masses greater than 1010 solar masses.

Original languageEnglish
Article numberA110
JournalAstronomy and Astrophysics
Volume534
DOIs
StatePublished - 2011

Scopus Subject Areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Galaxies: active
  • Galaxy: general
  • Methods: statistical
  • Quasars: general
  • X-rays: general

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