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相关论文: The Identification of EGRET Sources with Flat-Spec…

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We have conducted a multiwavelength study of several radio sources within or near the error boxes of EGRET unidentified sources at mid to high Galactic latitude, under the hypothesis that the radio sources are blazars and are thus the best…

天体物理学 · 物理学 2009-10-30 S. D. Bloom , R. C. Hartman , H. Terasranta , M. Tornikoski , E. Valtaoja

Statistical studies indicate that the 271 point sources of high-energy gamma rays belong to two groups: a Galactic population and an isotropic extragalactic population. Many unidentified extragalactic sources are certainly blazars, and it…

天体物理学 · 物理学 2009-11-10 P. M. Wallace , S. D. Bloom , M. S. Lewis

Using survey data, we have re-evaluated the correlation of flat spectrum radio sources with EGRET sources in the Northern sky. A likelihood analysis incorporating the radio and X-ray properties and the Gamma-ray source localization is used…

天体物理学 · 物理学 2009-11-07 David Sowards-Emmerd , Roger W. Romani , Peter F. Michelson

Context. A considerable fraction of the gamma-ray sources discovered with the Energetic Gamma-Ray Experiment Telescope (EGRET) remain unidentified. The EGRET sources that have been properly identified are either pulsars or variable sources…

We present a multiwavelength analysis of the high-energy gamma-ray source 3EG J2006-2321. The flux of this source above 100 MeV is shown to be variable on time scales of days and months. Optical observations and careful examination of…

天体物理学 · 物理学 2009-11-07 P. M. Wallace , J. P. Halpern , A. M. Magalhaes , D. J. Thompson

In preparation for GLAST, we have compiled a sample of blazar candidates to increase the pool of well studied AGN from which GLAST counterparts will be drawn. Sources were selected with our Figure of Merit (FoM) ranking; thus, they have…

We recently identified the blazar-like radio source G74.87+1.22 (B2013+370) as the counterpart of the high-energy gamma-ray source 3EG J2016+3657 in the Galactic plane. However, since most blazar identifications of EGRET sources are only…

天体物理学 · 物理学 2009-10-31 J. P. Halpern , M. Eracleous , R. Mukherjee , E. V. Gotthelf

The EGRET instrument on the Compton Gamma Ray Observatory (1991-2000) has positively detected high energy gamma-ray emission from more than 67 active galaxies of the blazar class. The majority of the EGRET blazars are flat-spectrum radio…

天体物理学 · 物理学 2009-11-06 R. Mukherjee

Blazars are radio-loud Active Galactic Nuclei (AGN) with relativistic jets oriented towards the observer's line-of-sight. Based on their optical spectra, blazars may be classified as flat-spectrum radio quasars (FSRQs) or BL Lacs. FSRQs are…

高能天体物理现象 · 物理学 2021-07-14 Emmanuel Uwitonze , Pheneas Nkundabakura , Tom Mutabazi

Published EGRET spectra from blazars extend only to 10 GeV, yet EGRET has detected approximately 2000 gamma-rays above 10 GeV of which about half are at high Galactic latitude. We report a search of these high-energy gamma-rays for…

天体物理学 · 物理学 2009-11-06 Brenda L. Dingus , David L. Bertsch

The 3rd EGRET Catalog of High-energy Gamma-ray Sources contains 170 unidentified sources, and there is great interest in the nature of these sources. One means of determining source class is the study of flux variability on time scales of…

天体物理学 · 物理学 2009-10-31 P. M. Wallace , D. L. Bertsch , S. D. Bloom , N. J. Griffis , R. C. Hartman , D. A. Kniffen , D. J. Thompson

We have conducted a radio pulsar survey of 56 unidentified gamma-ray sources from the 3rd EGRET catalog which are at intermediate Galactic latitudes (5 deg. < |b| < 73 deg.). For each source, four interleaved 35-minute pointings were made…

天体物理学 · 物理学 2008-11-26 F. Crawford , M. S. E. Roberts , J. W. T. Hessels , S. M. Ransom , M. Livingstone , C. R. Tam , V. M. Kaspi

The EGRET source 3EG J1835+5918 is the brightest and most accurately positioned of the as-yet unidentified high-energy gamma-ray sources at high Galactic latitude (l,b=89,25). We present a multiwavelength study of the region around it,…

天体物理学 · 物理学 2009-10-31 N. Mirabal , J. P. Halpern , M. Eracleous , R. H. Becker

We present a catalog of point gamma-ray sources detected by the EGRET detector aboard the Compton Gamma Ray Observatory. We have used the whole gamma-ray dataset of reprocessed photons at energies above 100 MeV together with new Galactic…

天体物理学 · 物理学 2009-11-13 Jean-Marc Casandjian , Isabelle A. Grenier

The variability of the high-energy gamma ray sources in the Third EGRET catalog is analyzed by a new method. We re-analyze the EGRET data to calculate a likelihood function for the flux of each source in each observation, both for…

天体物理学 · 物理学 2009-11-10 P. L. Nolan , W. F. Tompkins , I. A. Grenier , P. F. Michelson

A study of the statistics of cosmological black-hole jet sources is applied to EGRET blazar data, and predictions are made for GLAST. Black-hole jet sources are modeled as collimated relativistic plasma outflows with radiation beamed along…

天体物理学 · 物理学 2008-11-26 Charles D. Dermer

A comparison of AGN detected at gamma ray energies by EGRET with flat-spectrum radio sources observed in surveys for intraday variability reveals that a remarkably high fraction of EGRET blazars show significant interstellar scintillation…

天体物理学 · 物理学 2008-05-27 Hayley Bignall , Giuseppe Cimo , David Jauncey , Cliff Senkbeil , Jim Lovell , Simon Ellingsen

EGRET has detected 67 sources associated with active galactic nuclei. With the exception of radio galaxy Cen A, all are classified as belonging to the blazar class of active galactic nuclei. The cumulative exposure from multiple EGRET…

天体物理学 · 物理学 2010-12-03 P. Sreekumar , D. L. Bertsch , R. C. Hartman , P. L. Nolan , D. J. Thompson

Many sources in the fourth INTEGRAL/IBIS catalogue are still unidentified, since they lack an optical counterpart. An important tool that can help in identifying/classifying these sources is the cross-correlation with radio catalogues,…

The first three months of sky-survey operation with the Fermi Gamma Ray Space Telescope (Fermi) Large Area Telescope (LAT) reveals 132 bright sources at |b|>10 deg with test statistic greater than 100 (corresponding to about 10 sigma). Two…

高能天体物理现象 · 物理学 2009-09-30 A. A. Abdo
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