Results 21 to 30 of about 282 (177)
Correlation between Emission-line Luminosity and Gamma-Ray Dominance in the Blazar 3C 279
The Astrophysical Journal, 2023 Despite numerous studies, the origin of the γ -ray emission from blazars is still debated, in particular whether it is produced by leptonic or hadronic processes.
A. Dmytriiev +2 more
doaj +1 more source
Propagation of Very-high-energy γ-Rays from Distant Blazars
The Astrophysical Journal, 2023 We rederive the possible dependence of the redshift with a very-high-energy (VHE) γ -ray photon index. The results suggest that the universe to VHE γ -rays is becoming more transparent than expected.
L. J. Dong, Y. G. Zheng, S. J. Kang
doaj +1 more source
Redshift distributions of steep and flat-spectrum radio quasars and relativistic beaming [PDF]
Symposium - International Astronomical Union, 1986 Redshift distributions of almost complete samples of steep as well as flat-spectrum radio quasars are investigated. It is found that flat-spectrum (core-dominated) quasars contain a higher fraction of high redshifts (z ≳ 1.4) compared to steep-spectrum ones.
V. K. Kapahi, V. K. Kulkarni
openaire +1 more source
Classification of Fermi BCUs Using Machine Learning
The Astrophysical Journal, 2023 The Fermi Large Area Telescope (LAT) has detected 6659 γ -ray sources in the incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi-LAT catalog of γ -ray sources and 3743 of them are blazars, including 1517 blazar candidates of uncertain ...
Pei-yu Xiao +12 more
doaj +1 more source
Persistence of blazar state in flat-spectrum radio quasars
, 2022 Flat-spectrum radio quasars (FSRQs) whose brightness is dominated by a relativistically beamed core, are frequently found in 'blazar state' commonly inferred from a high optical polarization ( > 3%), and/or a large continuum variability. Here we use these two prime optical markers to investigate continuance of an FSRQ in blazar (or non-blazar) state
Chand, Krishan, Gopal-Krishna
openaire +2 more sources
THE LUMINOSITY FUNCTION OFFERMI-DETECTED FLAT-SPECTRUM RADIO QUASARS [PDF]
The Astrophysical Journal, 2012 Submitted to the Astrophysical ...
Ajello, M. +10 more
openaire +3 more sources
The Long-Lasting Activity in the Flat Spectrum Radio Quasar (FSRQ) CTA 102 [PDF]
Galaxies, 2019 The flat spectrum radio quasar CTA 102 ( z = 1.032 ) went through a tremendous phase of variability. Since early 2016 the gamma-ray flux level has been significantly higher than in previous years. It was topped by a four month long giant outburst, where peak fluxes were more than 100 times higher than the quiescence level.
Michael Zacharias +5 more
openaire +5 more sources
What powers the most relativistic jets? – II. Flat-spectrum radio quasars [PDF]
Monthly Notices of the Royal Astronomical Society, 2017 16 pages, 8 figures; accepted for publication in ...
Gardner, Emma, Done, Chris
openaire +4 more sources
Flat Spectrum Radio Quasar Evolution and the Gamma-ray Background [PDF]
Proceedings of the International Astronomical Union, 2013 AbstractWe discuss an analysis of the redshift evolutions and distributions of the gamma-ray luminosity and photon spectral index of flat spectrum radio quasar (FSRQ) type blazars. We utilize data from the Fermi Gamma-ray Space Telescope, with redshfits as determined from optical spectroscopy by Shaw et al. We find that FSRQs have evolved significantly
Jack Singal, Allan Ko, Vahe Petrosian
openaire +1 more source
Flat spectrum radio quasars: MAGIC results and unexpected features [PDF]
AIP Conference Proceedings, 2012 The detection of Flat Spectrum Radio Quasars (FSRQs) in the Very High Energy (VHE, E>100 GeV) range is challenging, mainly because of their steep soft spectra. Often neither the emission nor the variability features of recently discovered VHE-FSRQs can be explained with the models developed so far for BL Lacs.
De Caneva, G. +14 more
openaire +2 more sources