학술논문
Multi-band Optical Variability of the TeV Blazar PG 1553+113 in 2019
Document Type
Working Paper
Author
Dhiman, Vinit; Gupta, Alok C.; Kurtanidze, Sofia O.; Eglitis, I.; Strigachev, A.; Damljanovic, G.; Wiita, Paul J.; Gu, Minfeng; Gaur, Haritma; Vince, Oliver; Bachev, R.; Bisen, D. P.; Ibryamov, S.; Ivanidze, R. Z.; Jovanovic, Miljana D.; Kurtanidze, Omar M.; Nikolashvili, M. G.; Semkov, E.; Spassov, B.; Stojanovic, M.; Villarroel, Beatriz; Xu, Haiguang; Zhang, Zhongli
Source
Subject
Language
Abstract
We report the flux and spectral variability of PG 1553+113 on intra-night (IDV) to short-term timescales using BVRI data collected over 91 nights from 28 February to 8 November 2019 employing ten optical telescopes: three in Bulgaria, two each in India and Serbia, and one each in Greece, Georgia, and Latvia. We monitored the blazar quasi-simultaneously for 16 nights in the V and R bands and 8 nights in the V, R, I bands and examined the light curves (LCs) for intra-day flux and colour variations using two powerful tests: the power-enhanced F-test and the nested ANOVA test. The source was found to be significantly (> 99%) variable in 4 nights out of 27 in R-band, 1 out of 16 in V-band, and 1 out of 6 nights in I-band. No temporal variations in the colours were observed on IDV timescale. During the course of these observations the total variation in R-band was 0.89 mag observed. We also investigated the spectral energy distribution (SED) using B, V, R, and I band data. We found optical spectral indices in the range of 0.878+-0.029 to 1.106+-0.065 by fitting a power law to these SEDs of PG 1553+113. We found that the source follows a bluer-when-brighter trend on IDV timescales. We discuss possible physical causes of the observed spectral variability.
Comment: 13 pages,8 figures, 7 tables, Accepted for publication in MNRAS
Comment: 13 pages,8 figures, 7 tables, Accepted for publication in MNRAS