Strong gravitational lensing of blazar gamma-radiation and intergalactic magnetic fields

IF 3.6 2区物理与天体物理 Q1 PHYSICS, NUCLEAR

中国物理C Pub Date : 2024-01-01 DOI:10.1088/1674-1137/ad0b6a

Yu. N. Eroshenko

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Abstract

The influence of intergalactic magnetic fields on the strong gravitational lensing of blazar secondary gamma radiation is discussed. Currently, two cases of strong gravitational lensing of blazar gamma-radiation are known, where radiation is deflected by galaxies on the line of sight between the blazars and Earth. The magnetic field can affect the movements of electron-positron pairs generated by primary radiation, thereby changing the directions of secondary gamma radiation. It modifies the equation of the gravitational lens and leads to the dependence of the observed signal in the secondary gamma radiation on the energy of photons and magnetic field. Accordingly, it is possible, in principle, to estimate the intergalactic magnetic fields from the time delay of signals, from the angular position of images (for future high-resolution gamma-ray telescopes) or from the shape of the observed energy spectrum. This method is demonstrated by the example of the blazar B0218+357. In this case, however, it is not possible to obtain useful constraints due to the large distances to the blazar and lens galaxy. The result is only a lower limit on the magnetic field

G, which is weaker than other existing constraints. However, future discoveries of lensed blazars may provide more favorable opportunities for measuring the magnetic fields, especially with the help of a new generation of gamma-ray telescopes such as e-ASTROGAM, GECAM, and SVOM as well as future gamma-ray telescopes with a high angular resolution,

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蓝星伽马辐射的强引力透镜和星系间磁场

本文讨论了星系间磁场对炽星次级伽马辐射的强引力透镜效应的影响。目前，已知有两种对炽星伽马辐射的强引力透镜现象，即辐射被炽星和地球之间视线线上的星系偏转。磁场会影响原生辐射产生的电子-正电子对的运动，从而改变次级伽马辐射的方向。它修改了引力透镜方程，导致观测到的次级伽马辐射信号与光子能量和磁场有关。因此，原则上可以根据信号的时间延迟、图像的角度位置（用于未来的高分辨率伽马射线望远镜）或观测到的能谱形状来估计星系间磁场。B0218+357 这颗类星体的例子就证明了这种方法。然而，在这种情况下，由于与类星体和透镜星系之间的距离太远，无法获得有用的约束条件。结果只能得到磁场G的下限，比其他现有的约束条件要弱。不过，未来发现的透镜星云可能会为测量磁场提供更有利的机会，特别是在新一代伽马射线望远镜（如e-ASTROGAM、GECAM和SVOM）以及未来的高角度分辨率伽马射线望远镜的帮助下。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

中国物理C 物理-物理：核物理

CiteScore

6.50

自引率

8.30%

发文量

8976

审稿时长

1.3 months

期刊介绍： Chinese Physics C covers the latest developments and achievements in the theory, experiment and applications of: Particle physics; Nuclear physics; Particle and nuclear astrophysics; Cosmology; Accelerator physics. The journal publishes original research papers, letters and reviews. The Letters section covers short reports on the latest important scientific results, published as quickly as possible. Such breakthrough research articles are a high priority for publication. The Editorial Board is composed of about fifty distinguished physicists, who are responsible for the review of submitted papers and who ensure the scientific quality of the journal. The journal has been awarded the Chinese Academy of Sciences ‘Excellent Journal’ award multiple times, and is recognized as one of China''s top one hundred key scientific periodicals by the General Administration of News and Publications.