X-Ray Line-emitting Objects in XMM-Newton Observations: The Tip of the Iceberg

Abstract

We present preliminary results from a novel search for X-ray line-emitting objects (XLEOs) in XMM-Newton images. Three sources have been detected in a test-run analysis of 13 XMM-Newton observations. The three objects found are most likely extremely absorbed active galactic nuclei characterized by a column density N_H~10²⁴ cm^-2. Their redshift has been directly determined from the X-ray data, by interpreting the detected emission line as the 6.4 keV Fe line. The measured equivalent width of the X-ray line is, in all three cases, several keV. This pilot study demonstrates the success of our search method and implies that a large sample of XLEOs can be obtained from the public XMM-Newton data archive.