Investigation of the Flaring Activity of BL Lac in July–November 2021

IF 16.4 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Accounts of Chemical Research Pub Date : 2023-10-03 DOI:10.1134/S1063773723050067

L. S. Ugol’kova, M. S. Pshirkov, V. P. Goranskij, N. P. Ikonnikova, B. S. Safonov, A. M. Tatarnikov, E. V. Shimanovskaya, M. A. Burlak, M. D. Afonina

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Abstract

The source BL Lac exhibited an enhanced activity from August 2020 to July 2022. This activity peaked in July–August 2021. In this period the source reached historic brightness maxima in various energy ranges. Observations of this nonstandard maximum were carried out by the SAI staff of the Crimean Station of SAI and with the telescopes of the Caucasus Mountain Observatory (CMO SAI MSU). Optical and near-infrared photometric data as well as optical polarimetric data were obtained. When investigating the correlation between the optical and gamma-ray fluxes and between the optical and infrared fluxes, its high degree with an almost zero lag was confirmed—this means that the emission regions spatially coincide or are very close together. The degree of linear polarization in the investigated period changed in a wide range, reaching 20\({\%}\), with an anticorrelation between the degree of linear polarization and the brightness of the object having been observed. A similar pattern of variation was also observed in the preceding flares of this object. The changes in the electric vector position angle (EVPA) show a dependence on the rate of change of the object’s brightness. The EVPA changed greatly during flares and slowly at the times of a slow change in the intensity.

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2021年7月至11月BL Lac扩口活性调查

来源BL Lac在2020年8月至2022年7月期间表现出增强的活性。这一活动在2021年7月至8月达到峰值。在这一时期，光源在不同的能量范围内达到了历史亮度最大值。这一非标准最大值的观测是由SAI克里米亚站的SAI工作人员和高加索山天文台（CMO SAI MSU）的望远镜进行的。获得了光学和近红外光度数据以及光学偏振数据。在研究光学和伽马射线通量之间以及光学和红外通量之间的相关性时，证实了其几乎为零滞后的高度——这意味着发射区域在空间上重合或非常接近。在研究期间，线偏振度变化范围很广，达到20（｛\%｝），观察到线偏振度与物体亮度之间存在反相关性。在该天体之前的耀斑中也观察到了类似的变化模式。电矢量位置角（EVPA）的变化显示出对物体亮度变化率的依赖性。EVPA在耀斑期间变化很大，在强度缓慢变化时变化缓慢。

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来源期刊

Accounts of Chemical Research 化学-化学综合

CiteScore

31.40

自引率

1.10%

发文量

312

审稿时长

2 months

期刊介绍： Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance. Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.