DYNAMICAL BEHAVIOR OF X-RAY SPECTRA FROM MARKARIAN 766
| Autor: | Andrew C. Liebmann, Masaaki Takahashi, Sachiko Tsuruta, Y. Haba, Hideyo Kunieda, Rohta Takahashi |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | The Astrophysical Journal. 780:35 |
| ISSN: | 1538-4357 0004-637X |
| Popis: | Mrk 766, a bright narrow-line Seyfert 1, has been observed eight times by the XMM-Newton satellite. We carried out the analysis of the composite data from all of these observations together by applying a dynamical method. Through this analysis, we noted a longer timescale variability in addition to rapid short-time variability. This longer term variability is manifested by the presence of two distinct branches in flux-flux plots. Moreover, the data show the presence of absorbing material whose average thickness decreases gradually from ~2 × 1023 cm–2 during the dim state to ~1022 cm–2 as the source brightens to brighter states. To explain this longer timescale behavior and others already found self-consistently, we offer a promising model. In this model, the source is dim when a small emission region is covered by a small, denser portion of a partial-covering cloud; the source brightens as it becomes larger and covered predominantly by a less dense, larger region of the covering cloud. The short rapid variability, in contrast, is consistent with the highly variable power-law component from the coronal primary emission region, which is superimposed onto a less variable, ionized relativistic reflection component. Last, a possible presence of some unique soft flares is suggested. Unlike many other flares seen in the light curves, these flares occur only in the 0.3-2.0 keV soft band. These soft flares may be attributed to "hot spots" on the accretion disk. |
| Databáze: | OpenAIRE |
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