X-ray properties of LINERs

Citation
S. Komossa et al., X-ray properties of LINERs, ASTRON ASTR, 349(1), 1999, pp. 88-96
Citations number
109
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY AND ASTROPHYSICS
ISSN journal
00046361 → ACNP
Volume
349
Issue
1
Year of publication
1999
Pages
88 - 96
Database
ISI
SICI code
0004-6361(199909)349:1<88:XPOL>2.0.ZU;2-I
Abstract
We present an investigation of the X-ray properties of 13 LINERs based on R OSAT 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 descri bed by a powerlaw with photon index Gamma(X) approximate to -2.0 or thermal emission from gas with very subsolar abundances. The luminosities range be tween log L-x = 37.7 (NGC404) and 40.8 (NGC4450). No X-ray variability on t he 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 sour ces 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 PSP C instrumental resolution. L-X/L-B ratios are derived and emission mechanis ms that potentially contribute to the observed X-ray luminosities are discu ssed. We also examine the presence of second X-ray sources near the target source s both in terms of instrumental effects and in terms of 'real' sources with in the LINER galaxies.