The Composite Nature of Dust-obscured Galaxies (DOGs) at z similar to 2-3 in the COSMOS Field. II. The AGN Fraction

Riguccini L.A.; Treister E.; Menéndez-Delmestre K.; Cardamone C.; Civano F.; Gonçalves T.S.; Hasinger G.; Koekemoer A.M.; Lanzuisi G.; Floc'H E.L.; Lusso E.; Lutz D.; Marchesi S.; Miyaji T.; Pozzi F.; et. al.

Abstract

We present the X-ray properties of 108 Dust-Obscured Galaxies (DOGs; F-24 mu m/F-R > 1000) in the COSMOS field, all of which are detected in at least three far-infrared bands with the Herschel Observatory. Out of the entire sample, 22 are individually detected in the hard 2-8 keV X-ray band by the Chandra COSMOS Legacy survey, allowing us to classify them as AGN. Six (27%) of them are Compton-thick AGN candidates with column densities N-H > 10(24) cm(-2), while 15 are moderately obscured AGNs with 10(22) < N-H < 10(24) cm(-2). Additionally, we estimate AGN contributions to the IR luminosity (8-1000 mu m rest-frame) greater than 20% for 19 DOGs based on SED decomposition using Spitzer/MIPS 24 mu m and the five Herschel bands (100-500 mu m). Only 7 of these are detected in X-rays individually. We performed an X-ray stacking analysis for the 86 undetected DOGs. We find that the AGN fraction in DOGs increases with 24 mu m flux and that it is higher than that of the general 24 mu m population. However, no significant difference is found when considering only X-ray detections. This strongly motivates the combined use of X-ray and far-IR surveys to successfully probe a wider population of AGNs, particularly for the most obscured ones.

Más información

Título según WOS: The Composite Nature of Dust-obscured Galaxies (DOGs) at z similar to 2-3 in the COSMOS Field. II. The AGN Fraction
Título según SCOPUS: The Composite Nature of Dust-obscured Galaxies (DOGs) at z ? 2-3 in the COSMOS Field. II. The AGN Fraction
Título de la Revista: ASTRONOMICAL JOURNAL
Volumen: 157
Número: 6
Editorial: IOP PUBLISHING LTD
Fecha de publicación: 2019
Idioma: English
DOI:

10.3847/1538-3881/ab16cd

Notas: ISI, SCOPUS