ROSAT PSPC observations of the infrared quasar IRAS 13349+2438: evidence for a warm absorber with internal dust.
Abstract
The authors present spatial, temporal and spectral analyses of ROSAT Position Sensitive Proportional Counter (PSPC) observations of the infrared-loud quasar IRAS 13349+2438. IRAS 13349+2438 is the archetypal highly polarized radio-quiet QSO and has an optical/infrared luminosity of ≈2×1046erg s-1. The authors detect variability in the ROSAT count rate by a factor of 4.1 in about one year, and there is also evidence for ≈25 per cent variability within one week. They find no evidence for large intrinsic absorption of soft X-rays by "cold" neutral matter. These two facts have important consequences for the scattering plus transmission model of this object which was developed to explain its high wavelength dependent polarization and other properties. The soft X-ray variability makes electron scattering of most of the soft X-rays difficult without a very peculiar scattering mirror. The lack of significant intrinsic cold X-ray absorption together with the large observed E(B-V) suggests either a very peculiar system geometry or, more probably, absorption by "warm" ionized gas with internal dust. There is evidence for an ionized oxygen edge in the X-ray spectrum. IRAS 13349+2438 has many properties that are similar to those of "narrow-line" Seyfert 1s.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 1996
- DOI:
- 10.1093/mnras/278.2.326
- arXiv:
- arXiv:astro-ph/9508057
- Bibcode:
- 1996MNRAS.278..326B
- Keywords:
-
- Quasars: X-Ray Variations;
- Quasars: X-Ray Absorption;
- Quasars: Interstellar Dust;
- dust;
- extinction -- galaxies: active -- galaxies: individual: IRAS 13349+2438 -- X-rays: galaxies;
- Astrophysics
- E-Print:
- uuencoded compressed postscript. The preprint is also available at http://www.ast.cam.ac.uk/preprint/PrePrint.html