Gamma-rays in flat-spectrum AGN: Revisiting the fast jet hypothesis with the CJF sample
2010
academicJournal
Zugriff:
The recent release of the First Fermi-LAT Source Catalog solidified the predominant association of extragalactic gamma-ray emitters to active galaxies, in particular blazars. A tight connection between AGN jet kinematics and gamma-ray properties has been argued for, attributing the energetic emission from active galaxies to their highly relativistic outflows. We investigate the Caltech-Jodrell Bank flat-spectrum (CJF) sample to study the connection between AGN jet kinematics and their gamma-ray properties. The high number of sources included in the sample, in addition to the excellent kinematic data available, allows us to investigate the origin of gamma-ray emission in AGN. We identify the CJF sources detected in gamma-rays (by Fermi-LAT and EGRET). We use gamma-ray luminosities and the available VLBI kinematic data to look for correlations between gamma-ray and kinematic properties, as well as for differences between AGN classes (quasars, BL Lacs, radio galaxies). We also check the kinematics of the TeV sources in the CJF. 21.8% of the CJF has been detected in the gamma-rays. We find the detectability of BL Lacs significantly higher compared to quasars. gamma-detected sources show a wider apparent jet velocity distribution compared to the non-detected ones, but the maxima of both distributions are at similar values. No strong link between gamma-ray detectability and fast apparent jet speeds is found. A tentative correlation is found between gamma-ray luminosity and maximum apparent jet speeds, stronger for BL Lac and gamma-variable sources. We find non-radial jet motions to be important to gamma-ray emission. We suggest two-zone, spine-sheath, models as a possible explanation to our results. We find 2 out of 4 CJF TeV sources show superluminal jet speeds, in contrast to previous studies. ; Comment: final version, 14 pages, 8 figures, accepted in A&A
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Gamma-rays in flat-spectrum AGN: Revisiting the fast jet hypothesis with the CJF sample
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Autor/in / Beteiligte Person: | Karouzos, Marios ; Britzen, Silke ; Witzel, Arno ; Zensus, Anton ; Eckart, Andreas |
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Veröffentlichung: | 2010 |
Medientyp: | academicJournal |
DOI: | 10.1051/0004-6361/201015984 |
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