Bibcode
Branduardi-Raymont, G.; Mason, K. O.; Murdin, P. G.; Martin, C.; McKechnie, S. P.
Referencia bibliográfica
(ESA, ESLAB Symposium on X-Ray Astronomy in the EXOSAT Era, 18th, The Hague, Netherlands, Nov. 5-9, 1984) Space Science Reviews (ISSN 0038-6308), vol. 40, April 1985, p. 647-652.
Fecha de publicación:
4
1985
Número de citas
1
Número de citas referidas
1
Descripción
A ≡7 hour observation of the central part of the Coma cluster of
galaxies has been performed with the EXOSAT LE telescopes and CMA
detectors. Five serendipitous sources are detected within the inner 35
arcmin radius of the field. Optical spectroscopy demonstrates that at
least three of these are background AGN not associated with the cluster.
At the sensitivity level of EXOSAT exposure, one would have expected to
see only 0.01 background sources based on the Einstein Medium
Sensitivity Survey. The EXOSAT and Einstein results may be reconciled if
these AGN have a much softer average X-ray spectrum than previously
assumed.