The XMM deep survey in the CDF-S

VIII. X-ray properties of the two brightest sources

¹ ICREA and Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès, 1, 08028 Barcelona, Spain
e-mail: kazushi.iwasawa@icc.ub.edu
² INAF – Osservatorio Astronomico di Bologna, via Ranzani, 1, 40127 Bologna, Italy
³ Università di Bologna – Dipartimento di Astronomia, via Ranzani, 1, 40127 Bologna, Italy
⁴ Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802, USA
⁵ Instituto de Física de Cantabria (CSIC-UC), Avenida de los Castros, 39005 Santander, Spain
⁶ University Federico II, via Cintia, Building 6, 80126 Napoli, Italy
⁷ INFN Napoli, via Cintia, 80126 Napoli, Italy
⁸ Dipartimento di Fisica, Università di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma, Italy

Received: 30 September 2014
Accepted: 11 December 2014

Abstract

We present results from the deep XMM-Newton observations of the two brightest X-ray sources in the Chandra Deep Field South (CDFS), PID 203 (z = 0.544) and PID 319 (z = 0.742). The long exposure of 2.5 Ms over a 10 year period (net 4 yr with a 6 yr gap) makes it possible to obtain high quality X-ray spectra of these two Type I AGN with X-ray luminosity of 10⁴⁴ erg s^-1, which is the typical luminosity for low-redshift PG quasars, and track their X-ray variability both in flux and spectral shape. Both sources showed X-ray flux variability of ~10−20% in rms, which is similar in the soft (0.5−2 keV) and hard (2−7 keV) bands. PID 203, which has evidence for optical extinction, shows modest amount of absorption (N_H≤ 1 × 10²¹ cm^-2) in the X-ray spectrum. Fe K emission is strongly detected in both objects with EW ~ 0.2 keV. The lines in both objects are moderately broad and exhibit marginal evidence for variability in shape and flux, indicating that the bulk of the line emission comes from their accretion disks rather than distant tori.