ROSAT PSPC lightcurves are presented for the Seyfert galaxy NGC 3227 at two different epochs separated by 2 yr. These lightcurves show statistically significant variability, the most rapid being a factor of ≡2 increase in only ≡20 min in 1991. Spectral analysis shows that a simple power-law with only Galactic absorption can usually characterize the observed spectrum in both the low and high states. One high-state observation during 1993 is clearly peculiar with respect to the others. If included in the extraction of the high-state spectrum, the simple power-law model no longer provides an entirely acceptable fit. Adding either an (oxygen) edge (e.g. a warm absorber) or a cold absorber that partially covers the source enables the data to be fitted equally well.
Roentgenstrahlung from the Universe
- Pub Date:
- February 1996
- Seyfert Galaxies: X-Ray Variations;
- Seyfert Galaxies: X-Ray Light Curves;
- Seyfert Galaxies: X-Ray Spectra