• ESA uses cookies to track visits to our website only, no personal information is collected.
    By continuing to use the site you are agreeing to our use of cookies. OK
    Find out more about our cookie policy.
    • → European Space Agency

    • About Science & Technology

    • For Public

    • For Educators

    • ESA

    • Science & Technology

    • INTEGRAL

    • Missions
    • Show All Missions
    • Mission Home
    • Summary
    • Fact Sheet
    • Objectives
    • Mission Team
    • Industrial Team
    • Spacecraft
    • Spacecraft
    • 3D Model
    • Instruments
    • Mission Operations
    • Mission Operations
    • Launch Vehicle
    • Launch Campaign
    • Orbit/Navigation
    • Science Operations
    • ISDC
    • ISOC
    • Data Archive (ISDC)
    • Resources
    • News Archive
    • Multimedia Gallery
    • Publication Archive
    • Calendar of Events
    • Services
    • Contact Us
    • Subscribe
    • RSS feed
    • Terms and Conditions

    A deep INTEGRAL hard X-ray survey of the 3C 273/Coma region

    Publication date: 15 July 2008

    Authors: Paltani, S. et al.

    Journal: Astronomy & Astrophysics
    Volume: 485
    Issue: 3
    Page: 707-718
    Year: 2008

    Copyright: ESO

    We present an analysis of the deepest hard X-ray survey to date of about 2500 deg² performed by the IBIS instrument on board INTEGRAL in the 20-60 keV band, with a total exposure time of 4 Ms. We find 34 candidate sources, for which we try to find counterparts at other wavelengths. The ratio of Seyfert 1 to Seyfert 2 is significantly more than the ratio found in the optical. This effect may be explained in the framework of the receding-torus model, but could also be due to absorption columns large enough to affect the 20-60 keV band. None of the predicted Compton-thick objects with 1024 < NH < 1025 cm-2 is detected unambiguously; when taking lower limits on NH into account, the fraction of these objects is found to be lower than 24%. We do not see, but cannot exclude, a relationship between absorption and luminosity similar to what is seen in the 2-10 keV band. Our data suggests the possibility of a lack of objects with 1021 <= NH <= 1022 cm-2, which could be expected if absorption has two origins, for instance a torus-like structure and the host galaxy. We find that the Log N-Log S diagram of our sources is compatible with those obtained in other surveys in hard X-rays. Compared to models of the AGN population selected in the 2-10 keV band, the Log N-Log S diagram is generally in good agreement, but the NH distribution is significantly different, with significantly less unabsorbed sources (NH < 1022 cm-2) at a given flux limit compared to the models. In this survey, we resolve about 2.5% of the cosmic X-ray background in the 20-60 keV band. -- Remainder of abstract is truncated --

    Link to Publication

    Last Update: 01 August 2008

    • Shortcut URL
    • http://sci.esa.int/jump.cfm?oid=43184

    Connect with us

    • RSS
    • Youtube
    • Twitter
    •  Flickr
    • Google+
    • Livestream
    • Subscribe
    • Appstore
    • Twitter-2

    Follow ESA science