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Related papers: Patterns of variability in gamma-ray blazars

200 papers

Gamma-ray emitting blazars have been the targets of many recent or ongoing monitoring programmes. The resulting multi-wavelength data archives are ideal for studying the quiescent and variable behaviour of the blazar PKS 2155-304. Here,…

High Energy Astrophysical Phenomena · Physics 2017-02-15 Nikki Pekeur , Russ Taylor , Renée Kraan-Korteweg

We present a detailed temporal and spectral study of the blazar 3C\,279 using multi-wavelength observations from Swift-XRT, Swift-UVOT and Fermi-LAT during a flare in 2018 January. The temporal analysis of $\gamma$-ray light curve indicates…

High Energy Astrophysical Phenomena · Physics 2021-06-03 Zahir Shah , V. Jithesh , S. Sahayanathan , Ranjeev Misra , Naseer Iqbal

Blazars can be divided into two sub-classes namely high energy and low energy peaked blazars. In spectral energy distribution, the first synchrotron hump of the former class peaks in UV/X-rays and in IR/optical bands for the latter class.…

High Energy Astrophysical Phenomena · Physics 2017-12-20 Alok C. Gupta , Nibedita Kalita , Haritma Gaur , Kalpana Duorah

Blazars are strongly variable sources that occasionally show spectacular flares visible in various energy bands. These flares are often, but not always, correlated. In a number of cases the peaks of optical flares are found to be somewhat…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Mateusz Janiak , Marek Sikora , Krzysztof Nalewajko , Rafał Moderski , Greg M. Madejski

The EGRET experiment aboard the Compton Gamma-Ray Observatory (CGRO) has observed at energies above 100 MeV strong gamma-ray flares with short-term time variability from the gamma-ray blazars 3C 279 and PKS 1622-297. During these flaring…

We present a study of the flux distribution of a sample of 15 Intermediate and Low-energy peaked blazars using XMM-Newton observations in a total of 57 epochs on short-term timescales. We characterise the X-ray variability of all of the…

High Energy Astrophysical Phenomena · Physics 2022-11-07 Kiran Wani , Haritma Gaur

We present the results of a series of Swift and quasi simultaneous ground-based infra-red observations of the blazar 3C 454.3 carried out in April-May 2005 when the source was 10 to 30 times brighter than previously observed. We found 3C…

We analyze X-ray light curves of the blazars Mrk 421, PKS 2155-304, and 3C 273 using observations by the Soft X-ray Telescope on board AstroSat and archival XMM-Newton data. We use light curves of length 30-90 ks each from 3-4 epochs for…

High Energy Astrophysical Phenomena · Physics 2023-10-27 Joy Bhattacharyya , Ritesh Ghosh , Ritaban Chatterjee , Nabanita Das

OJ 287 is one of the most dynamic BL Lacertae objects that has exhibited behaviour representative of the entire blazar class and is also one of the best sources with simultaneous multi-wavelength coordinated data. Motivated by strong X-ray…

High Energy Astrophysical Phenomena · Physics 2025-09-10 Pankaj Kushwaha

The long term broadband spectral study of Flat Spectrum Radio Quasars during different flux states has the potential to infer the emission mechanisms and the cause of spectral variations. To scrutinize this, we performed a detailed…

High Energy Astrophysical Phenomena · Physics 2023-10-11 Aminabi Thekkoth , S. Sahayanathan , Zahir Shah , Vaidehi S. Paliya , C. D. Ravikumar

The gamma-ray emission of blazar jets shows a pronounced variability and this feature provides limits to the size and to the speed of the emitting region. We study the gamma-ray variability of bright blazars using data from the first 18…

High Energy Astrophysical Phenomena · Physics 2015-05-28 T. Sbarrato , L. Foschini , G. Ghisellini , F. Tavecchio

About twenty years of radio observations in five bands (from 4.8 to 37 GHz) of the BL Lac object GC 0109+224 (S2 0109+22, RGB J0112+227), are presented and analysed together with the optical data. Over the past ten years this blazar has…

Astrophysics · Physics 2016-08-16 Stefano Ciprini , Gino Tosti , Harri Teräsranta , Hugh D. Aller

We investigate the spectral properties of the brightest gamma-ray flares of blazars detected by the Fermi Large Area Telescope. We search for the presence of spectral breaks and measure the spectral curvature on typical time scales of a few…

High Energy Astrophysical Phenomena · Physics 2015-06-24 Susanna Kohler , Krzysztof Nalewajko

The quasar-type blazar 4C 38.41 (B3 1633+382) experienced a large outburst in 2011, which was detected throughout the entire electromagnetic spectrum. We present the results of low-energy multifrequency monitoring by the GASP project of the…

The long-term optical and infrared color variability of blazars has been investigated with the SMARTS monitoring data. The sample in this study consists of 49 flat spectrum radio quasars and 22 BL Lac objects. The fractional variability…

Astrophysics of Galaxies · Physics 2015-11-11 Bing-Kai Zhang , Xiao-Shan Zhou , Xiao-Yun Zhao , Ben-Zhong Dai

Blazars show optical and $\gamma$-ray flux variations that are generally correlated, although there are exceptions. Here we present anomalous behaviour seen in the blazar 3C 454.3 based on an analysis of quasi-simultaneous data at optical,…

High Energy Astrophysical Phenomena · Physics 2019-04-10 Bhoomika Rajput , C. S. Stalin , S. Sahayanathan , Suvendu Rakshit , Amit Kumar Mandal

The X-ray emission from blazars has been widely investigated using several space telescopes. In this work, we explored statistical properties of the X-ray variability in the blazars S5 0716+714, OJ 287, Mkn 501 and RBS 2070 using the…

The study of gamma-ray blazars is usually hindered due to the lack of information on their redshifts and on their low energy photon fields. This information is key to understand the effect on the gamma-ray absorption due to either…

High Energy Astrophysical Phenomena · Physics 2021-05-12 J. Becerra González , J. A. Acosta-Pulido , W. Boschin , R. Clavero , J. Otero-Santos , J. A. Carballo-Bello , L. Domínguez-Palmero

We present multiwavelength data for twelve blazars observed from 2008-2010 as part of an ongoing optical-infrared photometric monitoring project. Sources were selected to be bright, southern (dec < 20 deg) blazars observed by the Fermi…

High Energy Astrophysical Phenomena · Physics 2015-06-03 E. W. Bonning , C. M. Urry , C. Bailyn , M. Buxton , R. Chatterjee , P. Coppi , G. Fossati , J. Isler , L. Maraschi