TIME SERIES ANALYSIS OF GAMMA-RAY BLAZARS AND IMPLICATIONS FOR THE CENTRAL BLACK-HOLE MASS
TIME SERIES ANALYSIS OF GAMMA-RAY BLAZARS AND IMPLICATIONS FOR THE CENTRAL BLACK-HOLE MASS
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DOI：
10.1088/0004-637x/773/2/177
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发表时间：
2013-07
期刊：
影响因子：
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通讯作者：
K. Nakagawa;M. Mori
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文献类型：
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作者：
K. Nakagawa;M. Mori
耀变体类活动星系核（AGN）的辐射表现出快速的时间变化，这通常归因于中心超大质量黑洞附近的发射区的不稳定性。活动星系核的变化时间尺度在高能区一般较快，费米伽玛射线空间望远镜最近提供的GeV能区的数据使我们能够详细研究活动星系核的时间行为。由于它在扫描模式下的大视场，大多数天空区域每天可以观测几个小时，许多活动星系核的日光变曲线已经积累了4年以上。本文通过研究15个活动星系核在GeV能区光变曲线的归一化功率谱密度，研究了它们的时变特性。其中一个源，3C 454.3，显示了一个6.8 × 105 s的特定时间尺度，这个值表明，假设内部激波模型，中心黑洞的质量为（108-1010）M，这与其他估计一致。它还表明，典型的时间间隔喷射的斑点是（7-70）倍的史瓦西半径的光交叉时间。
Radiation from the blazar class of active galactic nuclei (AGNs) exhibits fast time variability which is usually ascribed to instabilities in the emission region near the central supermassive black hole. The variability time scale is generally faster in higher energy region, and data recently provided by the Fermi Gamma-ray Space Telescope in the GeV energy band enable a detailed study of the temporal behavior of AGN. Due to its wide field-of-view in the scanning mode, most sky regions are observed for several hours per day and daily light curves of many AGNs have been accumulated for more than 4 yr. In this paper we investigate the time variability of 15 well-detected AGNs by studying the normalized power spectrum density of their light curves in the GeV energy band. One source, 3C 454.3, shows a specific time scale of 6.8 × 105 s, and this value suggests, assuming the internal shock model, a mass for the central black hole of (108–1010) M☉ which is consistent with other estimates. It also indicates the typical time interval of ejected blobs is (7–70) times the light crossing time of the Schwarzschild radius.