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X-ray properties of LINERs
Stefanie Komossa 1,
Hans Böhringer 1 and
John P. Huchra 2
Received 6 April 1999 / Accepted 17 June 1999
We present an investigation of the X-ray properties of 13 LINERs based on ROSAT all-sky survey and pointed PSPC and HRI observations. Several sources are studied for the first time in X-rays. The X-ray spectra are best described by a powerlaw with photon index -2.0 or thermal emission from gas with very subsolar abundances. The luminosities range between (NGC 404) and 40.8 (NGC 4450). No X-ray variability on the timescale of hours/days is detected. This is in line with the suggestion that LINERs may accrete in the advection-dominated mode. On a longer term, one of the objects, NGC 2768, turns out to be slightly variable. Some sources appear to be extended at weak emission levels whereas the bulk of the X-ray emission is consistent with arising from a point source within the PSPC instrumental resolution. / ratios are derived and emission mechanisms that potentially contribute to the observed X-ray luminosities are discussed.
We also examine the presence of second X-ray sources near the target sources both in terms of instrumental effects and in terms of `real' sources within the LINER galaxies.
Key words: galaxies: active galaxies: fundamental parameters galaxies: ISM galaxies: nuclei X-rays: galaxies
Send offprint requests to: St. Komossa (email@example.com)
Online publication: August 25, 1999