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We study the quasi-simultaneous Spectral Energy Distributions (SED) of 48 LBAS blazars, collected within three months of the Fermi LAT Bright AGN Sample (LBAS) data taking period, combining Fermi and Swift data with radio NIR-Optical and…

High Energy Astrophysical Phenomena · Physics 2009-12-21 S. Raino' , E. Cavazzuti , S. Colafrancesco , P. Giommi , A. Tramacere , the Fermi-LAT Collaboration

The strong variability of blazars can be characterized by power spectral densities (PSDs) and Fourier frequency-dependent time lags. In previous work, we created a new theoretical formalism for describing the PSDs and time lags produced via…

High Energy Astrophysical Phenomena · Physics 2015-08-19 Justin D. Finke , Peter A. Becker

We investigate the evolution of spectral energy distribution (SED) and underlying electron energy distribution (EED) by modeling the nearly simultaneous broadband spectra of selected bright 4FGL blazars, in the context of a combined cooling…

High Energy Astrophysical Phenomena · Physics 2025-09-04 Muhammad S. Anjum , Shu-Jin Hou , Liang Chen , Zhigang Li , Minfeng Gu

The spectral energy distribution and variability of several blazars (Mkn 501, 1 ES 2344+51.4, PKS 2155-30.4, 1 ES 1218+30.4, 3C 454.3) along the blazar sequence is investigated using a selfconsistent and timedependent lepto-hadronic hybrid…

High Energy Astrophysical Phenomena · Physics 2011-09-12 Matthias Weidinger , Felix Spanier

Beppo}SAX contributed substantially to our understanding of the physics of blazars. This has been made possible mainly by its wide energy range and especially by its high energy detector. Together with the information coming from still…

Astrophysics · Physics 2009-11-10 Gabriele Ghisellini

With their emission mainly coming from a relativistic jet pointing towards us, blazars are fundamental sources to study extragalactic jets and their central engines, consisting of supermassive black holes (SMBHs) fed by accretion discs.…

The present status of the blazar spectral sequence is discussed, including new findings about blazars selected with different criteria than the original complete radio-samples. Despite extensive searches of blazars "breaking" the sequence,…

Astrophysics · Physics 2009-06-23 L. Maraschi , G. Ghisellini , F. Tavecchio , L. Foschini , R. M. Sambruna

Context. Blazar AO 0235+164, located at redshift z = 0.94, has undergone several sharp multi-spectral-range flaring episodes during the last decades. In particular, the episodes peaking in 2008 and 2015, that received extensive…

Blazar spectral energy distributions (SEDs) are double peaked and follow a self-similar sequence in luminosity. The so-called "blue" blazars, whose first SED component peaks at X-ray energies, are TeV sources, although with a relatively…

Astrophysics · Physics 2009-10-31 C. Megan Urry

Internal shocks propagating through an ambient radiation field, are subject to a radiative drag that, under certain conditions, can significantly affect their dynamics and, consequently, the evolution of the beaming cone of emission…

Astrophysics · Physics 2009-10-31 Avigdor Eldar , Amir Levinson

The average Spectral Energy Distributions (SED) of different classes of blazars from the radio to the gamma-ray band are studied adopting a "complete-sample" approach. The SED are globally similar, despite systematic differences in specific…

Astrophysics · Physics 2007-05-23 G. Fossati , A. Celotti , G. Ghisellini , L. Maraschi

We present the results of multiband observations of the blazar S5 0716+714 intra-night variability performed during 23 nights in the period from 04.2014 through 04.2015. The bluer-when-brighter trend is detected in both intra- and…

Astrophysics of Galaxies · Physics 2021-03-17 Marina S. Butuzova

The \gamma-ray loud blazars (flat spectrum radio quasars--FSRQs and BL Lacertae objects-BLs) are very bright in the \gamma-ray bands, which is perhaps associated with a beaming effect. Therefore, one can expect that the \gamma-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-11 J. H. Fan , J. H. Yang , J. Y. Zhang , T. X. Hua , Y. Liu , Y. P. Qin , Y. Huang

The broadband SEDs of blazars exhibit two broad spectral components, which in leptonic emission models are attributed to synchrotron radiation and synchrotron self-Compton (SSC) radiation of relativistic electrons. During high state phases,…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Michael Zacharias , Reinhard Schlickeiser

We present simultaneous optical and X-ray data from Swift for a sample of FSRQs selected from the EMSS survey. We present also a complete analysis of Swift and INTEGRAL data on 4 blazars recently discussed as possibly challenging the trends…

Astrophysics · Physics 2009-11-13 L. Maraschi , L. Foschini , G. Ghisellini , F. Tavecchio , R. M. Sambruna

Blazars optical emission is generally dominated by relativistic jets, although the host galaxy, accretion disk and broad line region (BLR) may also contribute significantly. Disentangling their contributions has been challenging for years…

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

We present EVN observations of seven BL Lac objects selected from the RGB sample. To investigate the intrinsic radiation property of BL Lac objects, we estimated the Doppler factor with the VLA or MERLIN core and the total 408 MHz…

Astrophysics · Physics 2009-11-13 Zhongzu Wu , D. R. Jiang , Minfeng Gu , Yi Liu

In a previous paper, we proposed a new method to select low-power BL Lacs (LPBLs) based on mid-infrared emission and flux contrast through the Ca II spectral break; that study led to the selection of a complete sample formed by 34 LPBLs…

Astrophysics of Galaxies · Physics 2016-02-17 Claudia M. Raiteri , Alessandro Capetti

Blazars are a class of active galactic nuclei which host relativistic jets oriented close to the observer's line of sight. Blazars have very complex variability properties. Flares, namely flux variations around the mean value with a…

High Energy Astrophysical Phenomena · Physics 2022-01-19 Ze-Rui Wang , Ruo-Yu Liu , Maria Petropoulou , Foteini Oikonomou , Rui Xue , Xiang-Yu Wang