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Astron. Astrophys. 361, 444-450 (2000)

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Multiwavelength observations of the field HS47.5/22 in Ursa Major *

II. AGN statistics

K. Molthagen

1 Max-Planck-Institut für Extraterrestrische Physik, 85740 Garching, Germany
2 Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany

Received 3 June 1999 / Accepted 12 July 2000


An analysis is given of the AGN found in the medium deep X-ray survey in the HQS field HS 47.5/22 . The [FORMULA] curve is in good agreement with values in the literature above [FORMULA] ergs cm-2 s- 1. Redshifts are now determined for 71 AGN detected in the X-ray survey. Complete optically and X-ray selected samples were derived. In the optical range, we find a completeness limit of [FORMULA], resulting in a complete optical sample of not more than 18 AGN. X-ray completeness is primarily determined by the identification status. Below [FORMULA] ergs cm- 2 s-1, more than 10% of the X-ray sources remain unidentified giving a complete sample of 26 AGN. Both the optical number-magnitude relation and the X-ray luminosity functions are in agreement with previous determinations. Thus we found no supporting evidence that this area in the sky shows a non-random AGN distribution. A few individual objects are described in detail, among them RX J1001.5+4659 - a possibly extended source connected to a small group of galaxies, and RX J0957.1+4815 - an X-ray selected QSO with deep absorption lines, perhaps a BAL.

Key words: galaxies: quasars: general – galaxies: quasars: individual: RX J0957.1+4815 – galaxies: quasars: individual: RX J0953.9+4617 – X-rays: galaxies

* Partly based on observations from the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institut für Astronomie, Heidelberg, jointly with the Spanish National Commission for Astronomy

Send offprint requests to: H.J. Wendker, Hamburger Sternwarte (hjwendker@hs.uni-hamburg.de)

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© European Southern Observatory (ESO) 2000

Online publication: October 2, 2000