The Variability of Hardness Ratio 1 observed by ROSAT: Narrow-Line Seyfert 1 Galaxies versus Broad-Line Seyfert 1 Galaxies
Abstract
We examined the correlation between the ROSAT Hardness Ratio 1 and Count Rates eight Narrow-line Seyfert 1 Galaxies (NLS1s) and 14 Broad-line Seyfert1 Galaxies (BLS1s). We found that six of the NLS1s show a positive HR1-CTs correlation, and seven of the BLS1s, a negative correlation. The other two NLS1s and seven BLS1s do not show any clear HR1-CTs correlation. Thus, the spectral behavior is statistically different for the NLS1s and BLS1s. The different behaviors can possibly be interpreted in terms of a stable `soft excess' that is strong in NLS1s and weak in BLS1s, plus a power law component, common to both, which softens with increasing flux.
- Publication:
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Chinese Journal of Astronomy and Astrophysics
- Pub Date:
- June 2002
- DOI:
- 10.1088/1009-9271/2/3/207
- arXiv:
- arXiv:astro-ph/0110569
- Bibcode:
- 2002ChJAA...2..207C
- Keywords:
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- galaxies: Seyfert;
- galaxies: active;
- X-ray: galaxies;
- Astrophysics
- E-Print:
- 8 pages, 3 figures, submitted to A&