X-Ray Spectral Study of AGN Sources Content in Some Deep Extragalactic XMM-Newton Fields |
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Authors: | M A Hassan B A Korany R Misra I A M Issa M K Ahmed F A Abdel-Salam |
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Institution: | (1) National Research Institute of Astronomy and Geophysics, Helwan, Cairo, Egypt;(2) The Faculty of Applied Science, Umm AL-Qura University, Makka, Saudi Arabia;(3) Inter-University Center for Astronomy and Astrophysics (IUCAA), Pune, India;(4) Faculty of Science, Cairo University, Cairo, Egypt;(5) Faculty of Science, Taibah University, Madina, Saudi Arabia; |
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Abstract: | We undertake a spectral study of a sample of bright X-ray sources taken from six XMM-Newton fields at high galactic latitudes,
where AGN are the most populous class. These six fields were chosen such that the observation had an exposure time more than
60 ksec, had data from the EPIC-pn detector in the full-Frame mode and lying at high galactic latitude |b|>25∘. The analysis started by fitting the spectra of all sources with an absorbed power-law model, and then we fitted all the
spectra with an absorbed power-law with a low energy black-body component model.The sources for which we added a black body
gave an F-test probability of 0.01 or less (i.e. at 99% confidence level), were recognized as sources that display soft excess. We
perform a comparative analysis of soft excess spectral parameters with respect to the underlying power-law one for sources
that satisfy this criterion. Those sources, that do not show evidence for a soft excess, based on the F-test probability at a 99% confidence level, were also fitted with the absorbed power-law with a low energy black-body component
model with the black-body temperature fixed at 0.1 and 0.2 keV. We establish upper limits on the soft excess flux for those
sources at these two temperatures. Finally we have made use of Aladdin interactive sky atlas and matching with NASA/IPAC Extragalactic
Database (NED) to identify the X-ray sources in our sample. For those sources which are identified in the NED catalogue, we
make a comparative study of the soft excess phenomenon for different types of systems. |
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