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The XMM deep survey in the CDF-S: II. A 9-20 keV selection of heavily obscured active galaxies at z > 1.7

Abstract: ABSTRACT: We present results on a search of heavily obscured active galaxies z > 1.7 using the rest-frame 9?20 keV excess for X-ray sources detected in the deep XMM-CDFS survey. Out of 176 sources selected with the conservative detection criteria (>8?) in the first source catalogue of Ranalli et al. (in prep.), 46 objects lie in the redshift range of interest with the median redshift ?z 2.5. Their typical rest-frame 10?20 keV luminosity is 1044 erg s?1, as observed. Among optically faint objects that lack spectroscopic redshift, four were found to be strongly absorbed X-ray sources, and the enhanced Fe K emission or absorption features in their X-ray spectra were used to obtain X-ray spectroscopic redshifts. Using the X-ray colour?colour diagram based on the rest-frame 3?5 keV, 5?9 keV, and 9?20 keV bands, seven objects were selected for their 9?20 keV excess and were found to be strongly absorbed X-ray sources with column density of NH ? 0.6 × 1024 cm?2, including two possible Compton thick sources. While they are emitting at quasar luminosity, ?3/4 of the sample objects are found to be absorbed by NH > 1022 cm?2. A comparison with local AGN at the matched luminosity suggests an increasing trend of the absorbed source fraction for high-luminosity AGN towards high redshifts

Otras publicaciones de la misma revista o congreso con autores/as de la Universidad de Cantabria

 Autoría: Iwasawa K., Gilli R., Vignali C., Comastri A., Brandt W.N., Ranalli P., Vito F., Cappelluti N., Carrera F.J., Falocco S., Georgantopoulos I., Mainieri V., Paolillo M.,

 Fuente: Astronomy and Astrophysics, 2012, 546, A84

Editorial: EDP Sciences

 Fecha de publicación: 09/10/2012

Nº de páginas: 8

Tipo de publicación: Artículo de Revista

 DOI: 10.1051/0004-6361/201220036

ISSN: 0004-6361,1432-0746

Proyecto español: AYA2010-21782-C03-01

Url de la publicación: https://doi.org/10.1051/0004-6361/201220036

Autores/as

IWASAWA, K.

GILLI, R.

VIGNALI, C.

COMASTRI, A.

BRANDT, W.N.

RANALLI, P.

VITO, F.

CAPPELLUTI, N.

GEORGANTOPOULOS, I.

MAINIERI, V.

PAOLILLO, M.