English
Related papers

Related papers: Multiwavelength Cross-Correlations and Flaring Act…

200 papers

Blazars are highly variable active galactic nuclei which emit radiation at all wavelengths from radio to gamma-rays. Polarized radiation from blazars is one key piece of evidence for synchrotron radiation at low energies and it also varies…

The first one started in 2012 July 16 (MJD 56124) and the second one in 2013 April 9 (MJD 56391). The multiwavelength data analysis shows that the $\gamma$-ray flare observed in 2012 was not detected in the hard-X ray bands. This result is…

High Energy Astrophysical Phenomena · Physics 2015-08-07 Nissim Fraija , José Ignacio Cabrera , Erika Benítez , David Hiriart

The flat-spectrum radio quasar 3C~454.3 throughout the years has presented very high activity phases (flares) in which the different wavebands increase their flux dramatically. In this work, we perform multiwavelength analysis from radio to…

High Energy Astrophysical Phenomena · Physics 2021-01-06 Raúl Antonio Amaya-Almazán , Vahram Chavushyan , Victor Manuel Patiño-Álvarez

We present the light curve data of a remarkable blazer 3C 454.3 (z=0.859) in optical, X-ray, and gamma-ray bands. Since January 2008, we have been monitoring this object using the 50 cm MITSuME, a optical telescope, and detected several…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Yutaro Tachibana , Nobuyuki Kawai , Sean Pike

Blazars present highly variable $\gamma$-ray emission. This variability, which can range from a few minutes to several years, is also observed at other wavelengths across the entire electromagnetic spectrum. We make use of the first 12…

High Energy Astrophysical Phenomena · Physics 2024-03-05 P. Peñil , J. Otero-Santos , M. Ajello , S. Buson , A. Domínguez , L. Marcotulli , N. Torres-Albà , J. Becerra González , J. A. Acosta-Pulido

Blazars display variable emission across the entire electromagnetic spectrum, with timescales that can range from a few minutes to several years. Our recent work has shown that a sample of five blazars exhibit hints of periodicity with a…

High Energy Astrophysical Phenomena · Physics 2023-10-20 P. Peñil , J. R. Westernacher-Schneider , M. Ajello , A. Domínguez , S. Buson , J. Otero-Santos , L. Marcotulli , N. Torres-Albà , J. Zrake

Aims. The observation of gamma -ray flares from blazar 0836+710 in 2011, following a period of quiescence, offered an opportunity to study correlated activity at different wavelengths for a high-redshift (z=2.218) active galactic nucleus.…

High Energy Astrophysical Phenomena · Physics 2015-06-16 A. Akyuz , D. J. Thompson , D. Donato , J. S. Perkins , L. Fuhrmann , E. Angelakis , J. A. Zensus , S. Larsson , K. Sokolovsky , O. Kurtanidze

Blazars are highly variable, radio-loud active galactic nuclei with jets oriented at a small angle to the line of sight. The observed emission of these sources covers the whole electromagnetic spectrum from radio frequencies up to the high…

High Energy Astrophysical Phenomena · Physics 2016-04-20 Alicja Wierzcholska

The active galactic nucleus 4C +28.07 is a flat spectrum radio quasar, one of the brightest at $\gamma$-ray energies. We study its multi-wavelength emission by analysing $\sim12.3$ years of \textit{Fermi-LAT} data in the $\gamma$-ray band…

High Energy Astrophysical Phenomena · Physics 2022-01-10 Davit Zargaryan , Jonathan Mackey , Thibault Barnouin , Felix Aharonian

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

Blazars are a small fraction of all extragalactic sources but, unlike other objects, they are strong emitters across the entire electromagnetic spectrum. Recent data in the microwave region of the electromagnetic spectrum have become…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-24 D. Gasparrini , E. Cavazzuti , P. Giommi , C. Pittori , S. Colafrancesco , Fermi-LAT collaboration

Blazars, a subset of powerful active galactic nuclei, feature relativistic jets that shine in a broadband electromagnetic radiation, e. g. from radio to TeV emission. Here I present the results of the studies that explore gamma-ray and…

High Energy Astrophysical Phenomena · Physics 2022-10-18 Gopal Bhatta

We present the results of extensive multi-waveband monitoring of the blazar 3C~279 between 1996 and 2007 at X-ray energies (2-10 keV), optical R band, and 14.5 GHz, as well as imaging with the Very Long Baseline Array (VLBA) at 43 GHz. In…

Blazars exhibit flares across the electromagnetic spectrum. Many $\gamma$-ray flares are highly correlated with flares detected at optical wavelengths; however, a small subset appears to occur in isolation, with little or no variability…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Nicholas R. MacDonald , Alan P. Marscher , Svetlana G. Jorstad , Manasvita Joshi

The radio, optical, and $\gamma$-ray light curves of the blazar S5 1803+784, from the beginning of the {\it Fermi} Large Area Telescope (LAT) mission in August 2008 until December 2018, are presented. The aim of this work is to look for…

High Energy Astrophysical Phenomena · Physics 2021-03-03 R. Nesci , S. Cutini , C. Stanghellini , F. Martinelli , A. Maselli , V. M. Lipunov , V. Kornilov , R. R. Lopez , A. Siviero , M. Giroletti , M. Orienti

We compare the \gamma-ray light curves of the blazars, constructed with data provided by the Fermi Large Area Telescope, with flux and polarization variations in the VLBI core and bright superluminal knots obtained via monthly monitoring…

High Energy Astrophysical Phenomena · Physics 2015-06-03 S. Jorstad , A. Marscher , I. Agudo , B. Harrison

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

We collect the 2LAC and MOJAVE quasi-simultaneous data to investigate the radio-gamma connection of blazars. The cross sample contains 166 sources. The statistic analysis based on this sample confirms positive correlations between these two…

High Energy Astrophysical Phenomena · Physics 2014-09-03 Fan Xu-Liang , Bai Jin-Ming , Liu Hong-Tao , Chen Liang , Liao Neng-Hui

Blazars are known to show periods of quiescence followed by outbursts visible throughout the electromagnetic spectrum. We present a novel maximum likelihood approach to capture this bimodal behavior by examining blazar radio variability in…

High Energy Astrophysical Phenomena · Physics 2017-03-30 I. Liodakis , V. Pavlidou , T. Hovatta , W. Max-Moerbeck , T. J. Pearson , J. L. Richards , A. C. S. Readhead

The origin of the multi-band activities (outbursts/flares) of blazars is still a heavily debated topic. Shock and magnetic reconnection have long been considered as possible triggers for the multi-band activities. In this paper, we present…

High Energy Astrophysical Phenomena · Physics 2019-09-04 N. Ding , Q. S. Gu , X. F. Geng , Ding-Rong Xiong , R. Xue , X. Y. Wang , X. T. Guo