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The SHEEP survey: Observing the hardest of the hard with Chandra
Author(s) -
Georgantopoulos I.,
Nandra K.,
Brotherton M.,
Ptak A.,
Zezas A.,
Papadakis I.
Publication year - 2003
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.200310009
Subject(s) - rosat , qsos , physics , astrophysics , redshift , galaxy , astronomy , limiting , flux (metallurgy) , mechanical engineering , materials science , engineering , metallurgy
Abstract Our ASCA hard (5‐10 keV) SHEEP (Survey High Energy Extragalactic Populations) survey covers 39 deg 2 and contains 69 sources down to a limiting flux of 10 –13 erg cm –2 s –1 . 35 of the sources have ROSAT counterparts and therefore reliable optical identifications. The ‘soft’ SHEEP/ROSAT sample appears to be dominated by QSOs and Seyfert‐1 galaxies. For the remaining 34 sources we are obtaining Chandra snapshot (5 ksec) and KPNO spectroscopic observations. Here, we report some preliminary results from this campaign. Although the sample with spectroscopic identifications is still very limited, it appears that we are observing a mixture of QSOs (one at a redshift of z = 0.5 is heavily obscured) and Narrow Line Galaxies.