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Related papers: Possible New Identifications for EGRET Sources

200 papers

There are a number of candidate sources that are considered to be responsible for the origin of the EGRET source 3EG J1746--2851 (Hartman et al. 1999). The lack of clear identification of this source with any known sources in this region is…

Astrophysics · Physics 2007-05-23 F. Yusef-Zadeh

PKS 1622-297 was detected as a source of gamma-rays by the EGRET experiment at energies above 100 MeV during a gamma-ray outburst June and July 1995. We analyzed the COMPTEL data (0.75 - 30 MeV) of this time period to investigate the…

More than half the sources in the Third EGRET (3EG) catalog have no firmly established counterparts at other wavelengths and are unidentified. Some of these unidentified sources have remained a mystery since the first surveys of the…

Astrophysics · Physics 2015-06-24 R. Mukherjee , J. P. Halpern

We report a deep optical imaging observation by the Subaru telescope for a very soft X-ray source RX J1836.2+5925, which has been suspected to be an isolated neutron star associated with the brightest as-yet unidentified EGRET source…

Astrophysics · Physics 2015-06-24 T. Totani , W. Kawasaki , N. Kawai

The radio sky is poorly sampled for rapidly varying transients because of the narrow field-of-view of most imaging radio telescopes at cm and shorter wavelengths. The emergence of sensitive long wavelength observations with intrinsically…

The dominant fraction of the extragalactic $\gamma$-ray sources are blazars, active galactic nuclei with jets inclined at a small angle to the line of sight. Apart from blazars, a few dozen narrow-line Seyfert 1 galaxies (NLS1) and a number…

High Energy Astrophysical Phenomena · Physics 2025-03-06 K. É. Gabányi , S. Frey , K. Perger , E. Kun

Context. The majority of bright extragalactic gamma-ray sources are blazars. Only a few radio galaxies have been detected by Fermi/LAT. Recently, the GHz-peaked spectrum source PKS 1718-649 was confirmed to be gamma-ray bright, providing…

High Energy Astrophysical Phenomena · Physics 2016-09-28 C. Müller , P. R. Burd , R. Schulz , R. Coppejans , H. Falcke , H. Intema , M. Kadler , F. Krauß , R. Ojha

We present results of Compton Gamma-Ray Observatory EGRET observations of the unidentified high-energy gamma-ray sources 2EG J1049-5847 (GEV J1047-5840, 3EG J1048-5840) and 2EG J1103-6106 (3EG J1102-6103). These sources are spatially…

Astrophysics · Physics 2009-10-31 V. M. Kaspi , J. R. Lackey , J. Mattox , R. N. Manchester , M. Bailes , R. Pace

The INTEGRAL observatory has discovered a variety of hard X-ray sources in the Galactic plane since its launch. Using GMRT, we have made repeated observations of these sources to search for the radio counterparts of seventeen of them at low…

Astrophysics · Physics 2009-11-11 M. Pandey , R. K. Manchanda , A. P. Rao , P. Durouchoux , Ishwara-Chandra

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…

Astrophysics · Physics 2008-11-26 Charles D. Dermer

The vast majority of the celestial gamma-ray sources detected so far have not yet been identified with secure counterparts at other wavelenghts. Here we report the preliminary evidence of a probable association between galaxy clusters and…

Astrophysics · Physics 2009-11-07 Sergio Colafrancesco

We have assembled an 8.4 GHz survey of bright, flat-spectrum (alpha > -0.5) radio sources with nearly uniform extragalactic (|b|>10 deg) coverage for sources brighter than S_{4.8 GHz} = 65 mJy. The catalog is assembled from existing…

The Third EGRET Catalog (3EG) lists 66 high-confidence identifications of sources with Active Galactic Nuclei (AGN). All are classified as belonging to the blazar class, with the only exception of the nearby radio galaxy Centaurus A. We…

Astrophysics · Physics 2009-11-10 V. Sguera , L. Bassani , A. Malizia , A. J. Dean , R. Landi , J. B. Stephen

We have conducted low-frequency radio observations with the Giant Metrewave Radio Telescope (GMRT) of 40 new hard X-ray sources discovered by the INTEGRAL satellite. This survey was conducted in order, to study radio emissions from these…

Astrophysics · Physics 2009-11-11 M. Pandey , A. P. Rao , R. Manchanda , P. Durouchoux , C. H. Ishwara-Chandra

We present optical spectroscopy of 62 objects selected from several samples of ultra steep spectrum (USS) radio sources. 46 of these are from our primary catalog, consisting of 669 sources with radio spectral indices alpha < -1.30 (S_nu ~…

The source CGRaBS~J0211$+$1051 (MG1 J021114+1051, z=0.20) flared up on 2011 January 23 in high-energy $\gamma$-rays as reported by {\it Fermi}/LAT. This event was followed by the increased activity at the UV, optical and radio frequencies…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Sunil Chandra , Kiran S Baliyan , Shashikiran Ganesh , Luigi Foschini

We report on a search for steep spectrum radio sources within the 95% confidence error ellipses of the Fermi unassociated sources from the Large Array Telescope (LAT). Using existing catalogs and the newly released GMRT all-sky survey at…

High Energy Astrophysical Phenomena · Physics 2016-07-27 D. A. Frail , K. P. Mooley , P. Jagannathan , H. T. Intema

High-energy observations of extreme BL Lac objects, such as 1ES0229+200 or 1ES 0347-121, recently focused interest both for blazar and jet physics and for the implication on the extragalactic background light and intergalactic magnetic…

High Energy Astrophysical Phenomena · Physics 2015-12-17 F. Tavecchio , G. Bonnoli

Blazars are radio-loud Active Galactic Nuclei (AGN) whose jets have a very small angle to our line of sight. Observationally, the radio emission are mostly compact or a compact-core with a 1-sided jet. With 2.5$^{\prime\prime}$ resolution…

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…

Astrophysics · Physics 2010-12-03 P. Sreekumar , D. L. Bertsch , R. C. Hartman , P. L. Nolan , D. J. Thompson