Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-11-03
Mon.Not.Roy.Astron.Soc. 347 (2004) L41
Astronomy and Astrophysics
Astrophysics
5 pages, 3 figures. MNRAS, in press
Scientific paper
10.1111/j.1365-2966.2004.07311.x
We present followup observations of five hard X-ray sources from the ASCA 5-10 keV SHEEP survey, which has a limiting flux of $\sim 10^{-13}$ erg cm$^{-2}$ s$^{-1}$. Chandra data have been obtained to improve the X-ray positions from a few arcmin to $<1''$, which allows unambiguous optical identification. While the objects almost certainly house AGN based on their X-ray luminosity, optical spectroscopy reveals a variety of properties. The identifications indicate that the SHEEP survey samples the same populations as deeper surveys which probe the origin of the X-ray background, but because the SHEEP sources are far brighter, they are more amenable to detailed followup work. We find a variety of classifications and properties, including a type II QSO, a galaxy undergoing star formation, and a broad-line AGN which has a very hard X-ray spectrum, indicating substantial absorption in the X-ray but none in the optical. Two objects have X-ray/optical flux ratios which, were they at an X-ray flux level typical of objects in Chandra deep surveys, would place them in the ``optically faint'' category. They are both identified with broad line QSOs at z$\sim 1$. Clearly this survey - which is relatively unbiased against obscured objects - is revealing a set of remarkable objects quite different to the familiar classes of AGN found in previous optical and soft X-ray surveys.
Brotherton Michael
Georgantopoulos Ioannis
Nandra Kirpal
Papadakis Iossif E.
No associations
LandOfFree
X-ray and optical counterparts of hard X-ray selected sources from the SHEEP survey: first results does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with X-ray and optical counterparts of hard X-ray selected sources from the SHEEP survey: first results, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and X-ray and optical counterparts of hard X-ray selected sources from the SHEEP survey: first results will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-231917