X-ray properties of LINERs
Abstract
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 {Gamma_x } ~ -2.0 or thermal emission from gas with very subsolar abundances. The luminosities range between log L_x = 37.7 (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. L_x/L_B 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.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1999
- DOI:
- 10.48550/arXiv.astro-ph/9907119
- arXiv:
- arXiv:astro-ph/9907119
- Bibcode:
- 1999A&A...349...88K
- Keywords:
-
- GALAXIES: ACTIVE;
- GALAXIES: FUNDAMENTAL PARAMETERS;
- GALAXIES: ISM;
- GALAXIES: NUCLEI;
- X-RAYS: GALAXIES;
- Astrophysics
- E-Print:
- 11 pages incl. 11 figures, A&