An XMM-Newton observation of Ton S180: constraints on the continuum emission in ultrasoft Seyfert galaxies
An XMM-Newton observation of Ton S180: constraints on the continuum emission in ultrasoft Seyfert galaxies
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Ton S180 的 XMM-Newton 观测：超软 Seyfert 星系中连续发射的约束
DOI：
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发表时间：
2002
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影响因子：
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通讯作者：
Penn State
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文献类型：
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作者：
S. Vaughan;T. Boller;A. Fabian;D. Ballantyne;W. Brandt;J. T. IoA;Cambridge;Mpe;Garching;Penn State
我们提出了一个明亮的，窄线，超软1型塞弗特星系Ton S180的XMM牛顿观测。0.3-10 keV的X射线光谱是陡峭和弯曲的，在2.5 keV以上有一个陡峭的斜率（r = 2.3），在较低的能量下有一个平滑的、无特征的过量发射。频谱可以充分参数化使用一个简单的双幂律模型。在观测过程中，源是强烈可变的，但仅显示出微弱的光谱可变性，分数可变性振幅在十多年的能量中保持近似恒定。弯曲的连续体形状和弱光谱的变化进行了讨论的各种物理模型的软X射线的过量发射，包括电离吸积盘的表面反射，热电子的软盘光子的逆康普顿散射，和康普顿化的混合热/非热分布的电子。我们强调的可能性，强软过剩可能产生的吸积能量耗散在炎热的，高层大气的假定吸积盘。
We present an XMM-Newton observation of the bright, narrow-line, ultrasoft type 1 Seyfert galaxy Ton S180. The 0.3-10 keV X-ray spectrum is steep and curved, showing a steep slope above 2.5 keV (r ∼ 2.3) and a smooth, featureless excess of emission at lower energies. The spectrum can be adequately parametrized using a simple double power-law model. The source is strongly variable over the course of the observation but shows only weak spectral variability, with the fractional variability amplitude remaining approximately constant over more than a decade in energy. The curved continuum shape and weak spectral variability are discussed in terms of various physical models for the soft X-ray excess emission, including reflection off the surface of an ionized accretion disc, inverse Compton scattering of soft disc photons by thermal electrons, and Comptonization by electrons with a hybrid thermal/non-thermal distribution. We emphasize the possibility that the strong soft excess may be produced by dissipation of accretion energy in the hot, upper atmosphere of the putative accretion disc.