English
Related papers

Related papers: Exploring the variability properties of gamma-ray …

200 papers

We present cross-correlation studies of gamma-ray (0.1-300 GeV), X-ray (0.2-10 keV) and optical (R-band) variability of a sample of 26 blazars during 2008-2016. The light curves are from Fermi-LAT, Swift-XRT, and the Yale-SMARTS blazar…

High Energy Astrophysical Phenomena · Physics 2020-04-08 Anwesh Majumder , Kaustav Mitra , Ritaban Chatterjee , C. M. Urry , C. D. Bailyn , Prantik Nandi

The X-ray, Ultraviolet, Optical emission from radio-quiet AGNs, black hole binaries, and other compact sources, in general, follow a lognormal flux distribution, a linear rms-flux relation, and a (broken) power-law power spectral densities…

High Energy Astrophysical Phenomena · Physics 2020-03-04 Pankaj Kushwaha , Atreyee Sinha , Ranjeev Misra , K. P. Singh , E. M. de Gouveia Dal Pino

The blazar 3C 454.3 was revealed by the Fermi Gamma-ray Space Telescope to be in an exceptionally high flux state in July 2008. Accordingly, we performed a multi-wavelength monitoring campaign on this blazar using IR and optical…

Astrophysics · Physics 2011-02-11 E. W. Bonning , C. Bailyn , C. M. Urry , M. Buxton , G. Fossati , L. Maraschi , P. Coppi , R. Scalzo , J. Isler , A. Kaptur

Blazars represent dominant population of the extragalactic $\gamma$-ray sources in the Universe. These sources exhibit some characteristic properties like strong and non-thermal continuum emission over the entire electromagnetic spectrum…

High Energy Astrophysical Phenomena · Physics 2020-10-07 K. K. Singh , P. J. Meintjes

We present results of X-ray spectral and time-domain variability analyses of 4 faint, "quiescent" blazars from the Swift-BAT 105-month catalog. We use observations from a recent, 5-month long NICER campaign, as well as archival BAT data.…

High Energy Astrophysical Phenomena · Physics 2023-02-01 Sergio A. Mundo , Richard Mushotzky

We present the results of a series of radio, optical, X-ray and gamma-ray observations of the BL Lac object S50716+714 carried out between April 2007 and January 2011. The multi-frequency observations were obtained using several ground and…

Characteristic variability timescales in blazar gamma-ray light curves can provide insight into the physical processes responsible for the gamma-ray variability. The power spectral density (PSD) is capable of revealing such timescales,…

High Energy Astrophysical Phenomena · Physics 2019-11-06 James L. Ryan , Aneta Siemiginowska , Malgosia Sobolewska , Jonathan Grindlay

We analyze average gamma-ray variability statistics for the sample of blazars detected by CGRO/EGRET. We re-reduce all the available EGRET observations and analyze light curves by Monte Carlo modeling of the variability statistics including…

Astrophysics · Physics 2007-05-23 P. Magdziarz , R. Moderski , G. M. Madejski

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 search through $\gamma$-ray data obtained with the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope and find 24 blazars (or candidates) that have a single clear flare event in their 9.5 year long-term light curves.…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Gege Wang , Zhongxiang Wang , Liang Chen , Jianeng Zhou , Yi Xing

We report a detailed analysis of $\gamma$-ray data of 2FGL J0509.9+1802 observed by the Large Area Telescope on board {\it Fermi} satellite, especially focusing on April 2013 when extraordinary $\gamma$-ray variability has been detected.…

High Energy Astrophysical Phenomena · Physics 2015-06-22 N. H. Liao , J. M Bai

The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope routinely detects the highly dust-absorbed, reddened, and MeV-peaked flat spectrum radio quasar PKS 1830-211 (z=2.507). Its apparent isotropic gamma-ray luminosity…

High Energy Astrophysical Phenomena · Physics 2015-06-23 The Fermi LAT Collaboration , A. A. Abdo , M. Ackermann , M. Ajello , A. Allafort , M. A. Amin , L. Baldini , G. Barbiellini , D. Bastieri , K. Bechtol , R. Bellazzini , R. D. Blandford , E. Bonamente , A. W. Borgland , J. Bregeon , M. Brigida , R. Buehler , D. Bulmash , S. Buson , G. A. Caliandro , R. A. Cameron , P. A. Caraveo , E. Cavazzuti , C. Cecchi , E. Charles , C. C. Cheung , J. Chiang , G. Chiaro , S. Ciprini , R. Claus , J. Cohen-Tanugi , J. Conrad , R. H. D. Corbet , S. Cutini , F. D'Ammando , A. de Angelis , F. de Palma , C. D. Dermer , P. S. Drell , A. Drlica-Wagner , C. Favuzzi , J. Finke , W. B. Focke , Y. Fukazawa , P. Fusco , F. Gargano , D. Gasparrini , N. Gehrels , N. Giglietto , F. Giordano , M. Giroletti , T. Glanzman , I. A. Grenier , J. E. Grove , S. Guiriec , D. Hadasch , M. Hayashida , E. Hays , R. E. Hughes , Y. Inoue , M. S. Jackson , T. Jogler , G. Jòhannesson , A. S. Johnson , T. Kamae , J. Knödlseder , M. Kuss , J. Lande , S. Larsson , L. Latronico , F. Longo , F. Loparco , B. Lott , M. N. Lovellette , P. Lubrano , G. M. Madejski , M. N. Mazziotta , J. Mehault , P. F. Michelson , T. Mizuno , M. E. Monzani , A. Morselli , I. V. Moskalenko , S. Murgia , R. Nemmen , E. Nuss , M. Ohno , T. Ohsugi , D. Paneque , J. S. Perkins , M. Pesce-Rollins , F. Piron , G. Pivato , T. A. Porter , S. Rainò , R. Rando , M. Razzano , A. Reimer , O. Reimer , L. C. Reyes , S. Ritz , C. Romoli , M. Roth , P. M. Saz Parkinson , C. Sgrò , E. J. Siskind , G. Spandre , P. Spinelli , H. Takahashi , Y. Takeuchi , T. Tanaka , J. G. Thayer , J. B. Thayer , D. J. Thompson , L. Tibaldo , M. Tinivella , D. F. Torres , G. Tosti , E. Troja , V. Tronconi , T. L. Usher , J. Vandenbroucke , V. Vasileiou , G. Vianello , V. Vitale , A. P. Waite , M. Werner , B. L. Winer , K. S. Wood

We study the correlation between gamma-ray and radio band radiation for 123 blazars, using the Fermi-LAT first source catalog (1FGL) and the RATAN-600 data obtained at the same period of time (within a few months). We found an apparent…

High Energy Astrophysical Phenomena · Physics 2015-05-20 T. Mufakharov , M. Mingaliev , Yu. Sotnikova , Ya. Naiden , A. Erkenov

A majority of blazars exhibit variable emission across the entire electromagnetic spectrum, observed over various time scales. In particular, discernible periodic patterns are detected in the $\gamma$-ray light curves of a few blazars, such…

High Energy Astrophysical Phenomena · Physics 2025-06-18 Alba Rico , A. Domínguez , P. Peñil , M. Ajello , S. Buson , S. Adhikari , M. Movahedifar

The Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope provides an unprecedented opportunity to study gamma-ray blazars. To capitalize on this opportunity, beginning in late 2007, about a year before the start of LAT…

Even with several thousand {\it Fermi}-LAT blazar detections, the $\gamma$-ray emission mechanism is poorly understood. We explore correlated optical/$\gamma$-ray flux variations for 178 {\it Fermi}-LAT blazars regularly monitored by KAIT,…

High Energy Astrophysical Phenomena · Physics 2019-07-31 I. Liodakis , R. W. Romani , A. V. Filippenko , D. Kocevski , W. Zheng

This work present the results of a multi-epoch observational study of the blazar S5\,1803+784, carried out from 2019 to 2023. The analysis is based on simultaneous data obtained from the Swift/UVOT/XRT, ASAS-SN, and Fermi-LAT instruments. A…

High Energy Astrophysical Phenomena · Physics 2025-03-27 Javaid Tantry , Ajay Sharma , Zahir Shah , Naseer Iqbal , Debanjan Bose

Recently, blazar 4C +27.50 was found to be flaring in gamma-rays since its detection with Fermi-LAT in 2008. For the first time, a dedicated temporal and spectral study of the blazar 4C +27.50 has been performed in this work to understand…

High Energy Astrophysical Phenomena · Physics 2025-04-29 Joysankar Majumdar , Sakshi Maurya , Raj Prince

High-redshift blazars are one of the most powerful monsters in the universe and $\gamma$-ray variability carries crucial information of their relativistic jets. In this work we present results of the first systematical temporal analysis of…

High Energy Astrophysical Phenomena · Physics 2018-02-14 Shang Li , Zi-Qing Xia , Yun-Feng Liang , Neng-Hui Liao , Yi-Zhong Fan

We investigate the variability properties of blazars in the GeV band using the data of the Fermi/LAT telescope. We find that blazars exhibit variability on the scales down to the minimal timescale resolvable by Fermi, which is a function of…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Ievgen Vovk , Andrii Neronov