Results 71 to 80 of about 18,989 (273)

THE NATURE OF TRANSITION BLAZARS [PDF]

open access: yesThe Astrophysical Journal, 2014
14 pages, 11 Figures, ApJ ...
J. J. Ruan   +6 more
openaire   +5 more sources

Doppler Factor Estimation for Fermi Blazars

open access: yesAstrophysical Journal, 2020
In this work, we exploit the luminosity of the broad-line region (BLR) for 50 Fermi blazars through matching the coordinates between the Sloan Digital Sky Survey catalog, Fermi Large Area Telescope Third Source Catalog, and the Fermi Large Area Telescope
Lixia Zhang   +4 more
semanticscholar   +1 more source

Constraining the Limiting Brightness Temperature and Doppler Factors for the Largest Sample of Radio-bright Blazars [PDF]

open access: yesAstrophysical Journal, 2018
Relativistic effects dominate the emission of blazar jets, complicating our understanding of their intrinsic properties. Although many methods have been proposed to account for them, the variability Doppler factor method has been shown to describe the ...
I. Liodakis   +5 more
semanticscholar   +1 more source

A model for periodic blazars [PDF]

open access: yesMonthly Notices of the Royal Astronomical Society, 2016
We describe a scenario to explain blazar periodicities with timescales of $\sim$ few years. The scenario is based on a binary super-massive black hole (SMBH) system in which one of the two SMBH carries a jet. We discuss the various mechanisms that can cause the jet to precess and produce corkscrew patterns through space with a scale of $\sim$ few pc ...
Antonio Stamerra   +3 more
openaire   +4 more sources

The contribution of Fermi-2LAC blazars to the diffuse TeV-PeV neutrino flux [PDF]

open access: yes, 2016
The recent discovery of a diffuse cosmic neutrino flux extending up to PeV energies raises the question of which astrophysical sources generate this signal. One class of extragalactic sources which may produce such high-energy neutrinos are blazars.
I. C. M. Aartsen   +319 more
semanticscholar   +1 more source

On the Nature of MeV Blazars [PDF]

open access: yesThe Astrophysical Journal, 2002
Accepted for publication in the Astrophysical ...
M. Blazejowski   +3 more
openaire   +3 more sources

Investigation of Two Fermi-LAT Gamma-Ray Blazars Coincident with High-energy Neutrinos Detected by IceCube [PDF]

open access: yesAstrophysical Journal, 2019
After the identification of the gamma-ray blazar TXS 0506+056 as the first compelling IceCube neutrino source candidate, we perform a systematic analysis of all high-energy neutrino events satisfying the IceCube realtime trigger criteria.
Fermi-LAT collaboration S. Garrappa   +341 more
semanticscholar   +1 more source

The Blazar Sequence 2.0 [PDF]

open access: yesGalaxies, 2016
This paper discusses the spectral energy distribution (SED) of all blazars with redshift detected by the Fermi satellite and listed in the 3LAC catalog. The so called “blazar sequence” from the phenomenological point of view will be updated, with no theory or modelling. It will be shown that: (i) pure data show that jet and accretion power are related;
openaire   +6 more sources

The Fermi blazar sequence [PDF]

open access: yesMonthly Notices of the Royal Astronomical Society, 2017
We revisit the blazar sequence exploiting the complete, flux limited sample of blazars with known redshift detected by the Fermi satellite after 4 years of operations (the 3LAC sample). We divide the sources into gamma-ray luminosity bins, collect all the archival data for all blazars, and construct their spectral energy distribution (SED). We describe
Gabriele Ghisellini   +4 more
openaire   +4 more sources

Characteristic Variability Timescales in the Gamma-Ray Power Spectra of Blazars [PDF]

open access: yesAstrophysical Journal, 2019
Characteristic variability timescales in blazar γ-ray light curves can provide insights into the physical processes responsible for γ-ray variability. The power spectral density (PSD) is capable of revealing such timescales, which may appear as breaks or
J. Ryan   +3 more
semanticscholar   +1 more source

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