Results 111 to 120 of about 16,452 (194)
Hunting Very High-energy-emitting (>100 GeV) High-synchrotron-peaked Blazars
The Astrophysical Journal Supplement SeriesVery high-energy (VHE; >100 GeV) γ -ray emission originates via some of the most extreme particle acceleration processes in the Universe. Considering beamed active galactic nuclei, i.e., blazars, only a small fraction, mainly high-synchrotron-peaked BL ...
Sushmita Agarwal, Vaidehi S. Paliya
doaj +1 more source
Fermi detected blazars seen by INTEGRAL
, 2009 Multiwavelength observations are essential to constrain physical parameters of the blazars observed by Fermi/LAT. Among the 187 AGN significantly detected in public INTEGRAL data above 20 keV by the imager IBIS/ISGRI, 20 blazars were detected.
Beckmann, V., Ricci, C., Soldi, S.
core +1 more source
Variability of Blazars and Blazar Models over 38 Years [PDF]
Galaxies, 2016 Since 1978, when BL Lac objects and violently variable quasars were married to become “blazars”, physical interpretations of the phenomenon have evolved. Remarkably, though, the general picture of relativistic jets beaming their radiation in our direction, proposed that year by Blandford and Rees, remains intact.
openaire +2 more sources
Galaxies, 2020 We use multi-frequency linear polarization observations from the University of Michigan blazar program (UMRAO), in combination with radiative transfer simulations of emission from a relativistic jet, to investigate the time-dependent flow conditions ...
Margo Aller +3 more
doaj +1 more source
TeV gamma rays from blazars beyond z=1?
, 2013 At TeV energies, the gamma-ray horizon of the universe is limited to redshifts z1, if the observed gamma rays are secondary photons produced in interactions of high-energy protons originating from the blazar jet and propagating over cosmological ...
A. Zech +4 more
core +1 more source
, 2003 This review paper discusses the past and present observations of gamma-ray blazars with both space and ground-based gamma-ray telescopes (such as EGRET and current TeV telescopes), and with the VLBA. I also discuss the more sensitive gamma-ray telescopes such as AGILE and GLAST that will become available over the next several years, and how ...
openaire +2 more sources
Extragalactic jets: the high energy view
, 2004 I review the current knowledge of high-energy emission from extragalctic jets. First I discuss gamma-ray emission from blazars, which provides us numerous precious information on the innermost portions of the relativistic jets. I describe the constraints
Tavecchio, Fabrizio
core +2 more sources
Optical Outburst of the Blazar S4 0954+658 in Early 2015
Galaxies, 2016 We analyze the behavior of the BL Lac object S4 0954+658 during an unprecedented bright optical flare in early 2015. The optical flare was accompanied by a powerful γ -ray flare and the detection of very-high-energy γ -ray emission.
Daria Morozova +8 more
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Infrared Colors of the gamma-ray detected blazars
, 2012 Blazars constitute the most enigmatic class of extragalactic gamma-ray sources, and their observational features have been ascribed to a relativistic jet closely aligned to the line of sight.
Abdo +23 more
core +1 more source
Time-Evolving SED of MKN421: A Multi-Band View and Polarimetric Signatures
Frontiers in Astronomy and Space Sciences, 2018 The most detailed temporal studies of the emission from blazars are usually done by trying to obtain a dense, simultaneous coverage of the source over a large multi-wavelength observational campaign.
Bernardo M. O. Fraga +4 more
doaj +1 more source