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| Paper: |
Chandra HETG Observation of the Ultrasoft Narrow-line Seyfert 1 Galaxy 1H 0707-495 |
| Volume: |
290, Active Galactic Nuclei: from Central Engine to Host Galaxy |
| Page: |
107 |
| Authors: |
Leighly, K. M.; Zdziarski, A. A.; Kawaguchi, T.; Matsumoto, C. |
| Abstract: |
A Chandra observation of the ultrasoft Narrow-line Seyfert 1 galaxy 1H0707-495 using the HETG spectrometer reveals a strong soft excess, a weak power law, and absorption near 1 keV that may be the direct result of the strong soft excess. We observed strong spectral variability in which the soft component varied much less than the hard component, a behavior that is both quite suggestive of soft-state X-ray binaries, and in contrast to the colorless variability of other NLS1s observed by Chandra and XMM-Newton. 1H 0707-495 was bright when we observed it, and a comparison of historical observations reveals suggestively bimodal behavior. We interpret this bimodality as the signature of the radiation pressure instability, and suggest that this instability may be expected in this object, resulting from a high accretion rate, and lack of strong corona that could stabilize the accretion disk. |
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