ROSAT Extended Medium-Deep Sensitivity Survey: Source Counts for 130 Fields
Abstract
We present an analysis of serendipitous sources detected in 130 high Galactic latitude, long-exposure ROSA T PSPC observations. By application of an efficient source detection technique and analyzing a larger number of fields compared to previous studies, we have sufficiently increased the sky coverage of the survey and are able to investigate the X-ray source population over almost three decades of intensity, from approximately 1.2 × 10-15 to approximately 7.0 × 10-13 ergs s-1 cm-2 in the 0.5-2.0 keV energy band. Using the 2678 detected sources, we refine the extragalactic log N-log S and find that the differential number-flux relation is well described by a broken power law which flattens from α = 2.55±0.08 above a flux of 2.2±0.2 x 10-14 s-1 cm-2 to 1.86±0.06 at fainter fluxes, which is in a good agreement with previous studies. At our limiting flux of 1.2 × 10-15 ergs s-1 cm-2, the detected (point) sources comprise 66±7% (68% confidence limits) of the X-ray background in the 1-2 keV band.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 1995
- DOI:
- 10.1086/176243
- Bibcode:
- 1995ApJ...451..553V
- Keywords:
-
- SURVEYS;
- X-RAYS: GALAXIES