Τίτλος:
Searching for luminous absorbed sources in the WISE AGN catalogue
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Mid-infrared (IR) colour selection techniques have proved to be very efficient in finding active galactic nuclei (AGN). This is because the AGN heats the surrounding dust producing warm mid-IR colours. Using the Wide-field Infrared Survey Explorer 3.6, 4.5 and 12 μm colours, the largest sample of IR selected AGN has already been produced containing 1.4 million AGN over the whole sky. Here, we explore the X-ray properties of this AGN sample by cross-correlating it with the subsample of the 3XMM X-ray catalogue that has available X-ray spectra and at the same time optical spectroscopy from Sloan Digital Sky Survey (SDSS). Our goal is to find rare luminous obscured AGN. Our final sample contains 65 QSOs with log vLv ≥ 46.2 erg s-1. This IR luminosity cut corresponds to log LX ≈ 45 erg s-1, at the median redshift of our sample (z = 2.3), that lies at the bright end of the X-ray luminosity function at z > 2. The X-ray spectroscopic analysis reveals seven obscured AGN having a column density NH > 1022 cm-2. Six of them show evidence for broad [C IV] absorption lines and five are classified as broad absorption line QSOs. We fit the optical spectra of our X-ray absorbed sources to estimate the optical reddening.We find that none of these show any obscuration according to the optical continuum. These sources add to the growing evidence for populations of luminous QSOs with evidence for substantial absorption by outflowing ionized material, similar to those expected to be emerging from their absorbing cocoons in the framework of AGN/galaxy co-evolution. © 2017 The Authors.
Συγγραφείς:
Mountrichas, G.
Georgantopoulos, I.
Secrest, N.J.
Ordovás-Pascual, I.
Corral, A.
Akylas, A.
Mateos, S.
Carrera, F.J.
Batziou, E.
Περιοδικό:
Monthly Notices of the Royal Astronomical Society
Εκδότης:
Oxford University Press
DOI:
10.1093/mnras/stx572
