OPTICAL SPECTROSCOPY OF X-RAY SOURCES IN THE EXTENDED CHANDRA DEEP FIELD SOUTH

Treister, E.; Virani, S; Gawiser, E; URRY, CM; Lira, P; Francke, I; Blanc, GA; Cardamone, CN; Damen, M; Taylor, EN; Schawinski, K

Abstract

We present the first results of our optical spectroscopy program aimed to provide redshifts and identifications for the X-ray sources in the Extended Chandra Deep Field South. A total of 339 sources were targeted using the IMACS spectrograph at the Magellan telescopes and the VIMOS spectrograph at the VLT. We measured redshifts for 186 X-ray sources, including archival data and a literature search. We find that the active galactic nucleus (AGN) host galaxies have on average redder rest-frame optical colors than nonactive galaxies, and that they live mostly in the "green valley." The dependence of the fraction of AGNs that are obscured on both luminosity and redshift is confirmed at high significance and the observed AGN spatial density is compared with the expectations from existing luminosity functions. These AGNs show a significant difference in the mid-IR to X-ray flux ratio for obscured and unobscured AGNs, which can be explained by the effects of dust self-absorption on the former. This difference is larger for lower luminosity sources, which is consistent with the dust opening angle depending on AGN luminosity. © 2009. The American Astronomical Society. All rights reserved..

Más información

Título según WOS: OPTICAL SPECTROSCOPY OF X-RAY SOURCES IN THE EXTENDED CHANDRA DEEP FIELD SOUTH
Título según SCOPUS: Optical spectroscopy of X-ray sources in the extended chandra deep field south
Título de la Revista: ASTROPHYSICAL JOURNAL
Volumen: 693
Número: 2
Editorial: IOP PUBLISHING LTD
Fecha de publicación: 2009
Página de inicio: 1713
Página final: 1727
Idioma: English
URL: http://stacks.iop.org/0004-637X/693/i=2/a=1713?key=crossref.3b71fe75ff542e86922333067362b307
DOI:

10.1088/0004-637X/693/2/1713

Notas: ISI, SCOPUS