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Astron. Astrophys. 353, 487-497 (2000)

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Peculiar properties of 2 unusually X-ray bright early type galaxies

G. Trinchieri 1 and W. Pietsch 2

1 Osservatorio Astronomico di Brera, via Brera 28, 20121 Milano, Italy
2 Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse, 85740 Garching, Germany

Received 16 September 1999 / Accepted 19 October 1999


Two X-ray bright early type galaxies, selected for their unusually high X-ray to optical flux ratio, have been observed at high spatial resolution with the ROSAT HRI. Both sources are clearly extended ([FORMULA] kpc in radius), thus excluding a nuclear origin of the high X-ray emission. A small group of galaxies observed around IC 1262 could be the most natural explanation for the high X-ray luminosity observed. NGC 6159 could be similarly explained, although there are to date no spectroscopic confirmations of a group of galaxies associated with it. The X-ray properties of these two sources are discussed in the context of the properties of groups of galaxies. A peculiar very bright feature, in the shape of an arc, is detected at the center of the IC 1262 image. This could be the signature of a recent merger, or of peculiar high velocities in the group.

Key words: galaxies: individual: IC 1262 – galaxies: individual: NGC 6159 – X-rays: galaxies

Send offprint requests to: G. Trinchieri

Correspondence to: ginevra@brera.mi.astro.it

© European Southern Observatory (ESO) 2000

Online publication: December 17, 1999