The discovery of very red counterparts to faint X-ray sources
Abstract
We present deep K-band imaging at the positions of four very faint X-ray sources found in the UK ROSAT Deep Survey to have no optical counterpart brighter than R~23. Likely identifications are found within the ROSAT error circle in all four fields with R-K colours of between 3.2+/-0.4 and 6.4+/-0.6. From a consideration of the R-K colours and X-ray to optical luminosity ratios of the candidate identifications, we tentatively classify two of the X-ray sources as very distant (z~1) clusters of galaxies, one as a narrow emission line galaxy and one as an obscured QSO.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- December 1997
- DOI:
- 10.1093/mnras/292.2.378
- arXiv:
- arXiv:astro-ph/9708227
- Bibcode:
- 1997MNRAS.292..378N
- Keywords:
-
- X Ray Sources;
- Faint Objects;
- Rosat Mission;
- Error Analysis;
- Galactic Clusters;
- Quasars;
- Extremely High Frequencies;
- Visible Spectrum;
- Luminosity;
- Astronomy;
- GALAXIES: ACTIVE;
- GALAXIES: CLUSTERS: GENERAL;
- COSMOLOGY: OBSERVATIONS;
- DIFFUSE RADIATION;
- INFRARED: GALAXIES;
- Astrophysics
- E-Print:
- 7 pages, LaTeX, 7 figures (1 postscript file each). Uses mn.sty and epsf.sty. Accepted by MNRAS. For more information see http://www.astro.soton.ac.uk/~amn/UKdeep