ROSAT PSPC observations of NGC 7469 and Ark 120.
Abstract
We present spatial, temporal and spectral analyses of ROSAT Position Sensitive Proportional Counter (PSPC) observations of the Seyfert 1 galaxies NGC 7469 and Ark 120. Both of these sources show evidence for excess emission and more complex 0.1-2.5 keV spectra than are predicted by simple extrapolations of higher energy power laws. We find that the spectrum of NGC 7469 can be explained by models that have secondary power-law, secondary bremsstrahlung, secondary blackbody or emission-line components. We find evidence for 0.1-2.5 keV intensity variability of NGC 7469. The spectrum of Ark 120 is better described by models with secondary continuum components than by models with sharper spectral features. We discuss the agreement between X-ray and ultraviolet observations of these sources and examine the observations in the context of accretion disc reflection models. The inner parts of discs are likely to be reflective below ~0.24 keV, and this reflectivity complicates simple models of the soft excess.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- December 1993
- DOI:
- 10.1093/mnras/265.4.996
- Bibcode:
- 1993MNRAS.265..996B
- Keywords:
-
- Seyfert Galaxies;
- X Ray Spectra;
- Emission Spectra;
- Stellar Models;
- Light Curve;
- Sky Surveys (Astronomy);
- Spectrum Analysis;
- X Ray Astronomy;
- Astrophysics