THE SIZES OF THE X-RAY AND OPTICAL EMISSION REGIONS OF RXJ 1131–1231
THE SIZES OF THE X-RAY AND OPTICAL EMISSION REGIONS OF RXJ 1131–1231
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DOI：
10.1088/0004-637x/709/1/278
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发表时间：
2009-06
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影响因子：
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通讯作者：
X. Dai;C. Kochanek;G. Chartas;S. Kozłowski;C. Morgan;G. Garmire;E. I. O. Astronomy;U. Michigan
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文献类型：
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作者：
X. Dai;C. Kochanek;G. Chartas;S. Kozłowski;C. Morgan;G. Garmire;E. I. O. Astronomy;U. Michigan
我们使用 z = 0.658 类星体 RXJ 1131–1231 的四张图像的引力微透镜来测量类星体的光学和 X 射线发射区域的大小。静止帧 400 nm 处光盘的（正面）标度长度为 Rλ,O = 1.3 × 1015 cm，而静止帧 0.3–17 keV X 射线发射的半光半径为 R1/2,X = 2.3 × 1014 cm。形式不确定性因子分别为 1.6 和 2.0。除了 X 射线尺寸的下限之外，对于分析中使用的先验的任何变化，结果都非常稳定。根据Hβ线宽，我们估计黑洞质量为M1131≃108M☉，对应的引力半径为rg≃2×1013cm。因此，X 射线发射出现在~10rg 的尺度上，400 nm 发射出现在~70rg 的尺度上。这种尺寸的标准薄盘应该比观察到的要亮得多。可能的解决方案是具有更平坦的温度分布，或者在发射后将大部分光通量分散到更大的范围内。虽然我们的计算没有优化以限制透镜星系中的暗物质部分，但暗物质主导的模型受到青睐。凭借在广泛频率范围内良好采样的光学和 X 射线光曲线，扩展我们的分析以完全绘制吸积盘结构作为波长的函数将不存在困难。
We use gravitational microlensing of the four images of the z = 0.658 quasar RXJ 1131–1231 to measure the sizes of the optical and X-ray emission regions of the quasar. The (face-on) scale length of the optical disk at rest frame 400 nm is Rλ,O = 1.3 × 1015 cm, while the half-light radius of the rest frame 0.3–17 keV X-ray emission is R1/2,X = 2.3 × 1014 cm. The formal uncertainties are factors of 1.6 and 2.0, respectively. With the exception of the lower limit on the X-ray size, the results are very stable against any changes in the priors used in the analysis. Based on the Hβ line width, we estimate that the black hole mass is M1131 ≃ 108 M☉, which corresponds to a gravitational radius of rg ≃ 2 × 1013 cm. Thus, the X-ray emission is emerging on scales of ∼10rg and the 400 nm emission on scales of ∼70rg. A standard thin disk of this size should be significantly brighter than observed. Possible solutions are to have a flatter temperature profile or to scatter a large fraction of the optical flux on larger scales after it is emitted. While our calculations were not optimized to constrain the dark matter fraction in the lens galaxy, dark matter-dominated models are favored. With well-sampled optical and X-ray light curves over a broad range of frequencies, there will be no difficulty in extending our analysis to completely map the structure of the accretion disk as a function of wavelength.