A Method for Locating a High-energy Dissipation Region in a Blazar
A Method for Locating a High-energy Dissipation Region in a Blazar
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DOI：
10.3847/1538-4357/aac20a
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发表时间：
2017-11
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影响因子：
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通讯作者：
D. Yan;Qingwen Wu;X. Fan;Jian-cheng Wang;Li Zhang
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作者：
D. Yan;Qingwen Wu;X. Fan;Jian-cheng Wang;Li Zhang
耀变体喷流中伽马射线的产生地点是一个尚未解决的问题。我们提出了一种方法来定位一个伽玛射线发射区的框架内的一个区域的发射模型。通过对核位移效应的测量，可以推断喷流射电核的磁场强度（B′）与这些射电核到中心超大质量黑洞（SMBH）的距离（R）之间的关系。因此，一旦获得伽马射线发射区中的磁场强度（），就可以使用B′-R的关系来导出伽马射线发射区到SMBH的距离（Rdiss）。在这里，我们评估的下限，通过使用的标准，光学可变性的时间尺度tvar应该大于或等于同步辐射冷却的时间尺度的电子发射可见光子。我们用PSK 1510-089和BL Lacertae的观测结果检验了该方法，并推导出PSK 1510-089的pc和BL Lacertae的pc，其中PSK 1510-089的tvar为几小时，BL Lacertae的tvar为几分钟。这里，δD是多普勒因子，A是康普顿优势（即，康普顿与同步加速器峰值亮度的比率）。
The production site of gamma-rays in a blazar jet is an unresolved problem. We present a method to locate a gamma-ray emission region in the framework of a one-zone emission model. From measurements of the core-shift effect, the relation between the magnetic field strengths (B′) in the radio cores of the jet and the distances (R) of these radio cores from the central supermassive black hole (SMBH) can be inferred. Therefore, once the magnetic field strength in the gamma-ray emission region ( ) is obtained, one can use the relation of B′–R to derive the distance (Rdiss) of the gamma-ray emission region from the SMBH. Here, we evaluate the lower limit of by using the criteria that the optical variability timescale tvar should be longer than or equal to the synchrotron radiation cooling timescale of the electrons that emit optical photons. We test the method with the observations of PSK 1510-089 and BL Lacertae, and derive pc for PSK 1510-089 with tvar ∼ a few hours and pc for BL Lacertae with tvar ∼ a few minutes. Here, δD is the Doppler factor and A is the Compton dominance (i.e., the ratio of the Compton to the synchrotron peak luminosities).