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Microquasars, X-ray binary systems that generate relativistic jets, were discovered in our Galaxy in the last decade of the XXth century. Their name indicates that they are manifestations of the same physics as quasars but on a completely…

Astrophysics · Physics 2009-11-11 M. M. Kaufman Bernado

We present high-resolution radio interferometric imaging observations of the radio source NVSS J182659+343113 (hereafter J1826+3431), the proposed radio counterpart of the ${\gamma}$-ray source, 3EG J1824+3441 detected by the Energetic…

Astrophysics of Galaxies · Physics 2020-09-16 Patrik Milán Veres , Krisztina Éva Gabányi , Sándor Frey

3EG J1835+5918 is the brightest of the so-called unidentified EGRET sources at intermediate galactic latitude (l,b)=(89,25). We obtained complete radio, optical, and X-ray coverage of its error box, discovering a faint ultrasoft X-ray…

Astrophysics · Physics 2007-05-23 N. Mirabal , J. Halpern , R. Mukherjee , E. Gotthelf , F. Camilo

We perform a blind search for the variability of the gamma-ray sky in the energy range E>1 GeV using 308 weeks of the Fermi-LAT data. We use the technique based on the comparison of the weekly photon counts and exposures in sky pixels by…

High Energy Astrophysical Phenomena · Physics 2015-12-22 M. S. Pshirkov , G. I. Rubtsov

An Isotropic Diffuse Gamma-Ray Background (IDGRB) in the spectral range 30-10,000 MeV was first reported in the early 1970's using measurements made by the SAS-2 instrument. Data recorded by the Energetic Gamma Ray Experiment Telescope…

Astrophysics · Physics 2007-05-23 T. D. Willis

The extragalactic gamma-ray sky is dominated by the emission arising from blazars, one of the most peculiar classes of radio-loud active galaxies. Since the launch of Fermi several methods were developed to search for blazars as potential…

High Energy Astrophysical Phenomena · Physics 2015-06-24 F. Ricci , F. Massaro , M. Landoni , R. D'Abrusco , D. Milisavljevic , D. Stern , N. Masetti , A. Paggi , Howard A. Smith , G. Tosti

A significant fraction ($\sim 30$ %) of the high-energy gamma-ray sources listed in the second $\textit{Fermi}$ LAT (2FGL) catalog are still of unknown origin, being not yet associated with counterparts at lower energies. In order to…

High Energy Astrophysical Phenomena · Physics 2015-06-19 A. Paggi , F. Massaro , R. D'Abrusco , H. A. Smith , N. Masetti , M. Giroletti , G. Tosti , S. Funk

According to radiative models, radio galaxies are predicted to produce gamma-rays from the earliest stages of their evolution onwards. The study of the high-energy emission from young radio sources is crucial for providing information on…

High Energy Astrophysical Phenomena · Physics 2022-01-05 Giacomo Principe , Leonardo Di Venere , Giulia Migliori , Monica Orienti , Filippo D'Ammando

During its nine-year lifetime, the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) detected 1506 cosmic photons with measured energy E>10 GeV. Of this number, 187 are found within 1 degree of…

Astrophysics · Physics 2009-11-10 D. J. Thompson , D. L. Bertsch , R. H. O'Neal

I present a catalogue of positions and correlated flux densities of 109 compact extragalactic radio sources in the Galactic plane determined from analysis of a 48 hour VLBI experiment at 22 GHz with the European VLBI Network. The median…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-26 Leonid Petrov

We apply a likelihood analysis to pulsar detections, pulsar upper limits, and diffuse background measurements from the OSSE and EGRET instruments on the Compton Gamma Ray Observatory to constrain the luminosity law for gamma-ray pulsars and…

Astrophysics · Physics 2009-10-31 M. A. McLaughlin , J. M. Cordes

We studied the problematic of uncertainties in the diffuse gamma radiation apparent in stacking analysis of EGRET data at low Galactic latitudes. Subsequently, we co-added maps of counts, exposure and diffuse background, and residuals, in…

Astrophysics · Physics 2008-11-26 Analia N. Cillis , Olaf Reimer , Diego F. Torres

According to radiative models, radio galaxies and quasars are predicted to produce gamma rays from the earliest stages of their evolution. Exploring their high-energy emission is crucial for providing information on the most energetic…

There is active interest in the extent to which unresolved gamma-ray pulsars contribute to the galactic diffuse emission, and whether unresolved gamma-ray pulsars could be responsible for the excess of diffuse galactic emission above 1 GeV…

Astrophysics · Physics 2007-05-23 Martin Pohl , Gottfried Kanbach , Stan D. Hunter , Brian B. Jones

We describe the properties of the blazars detected by EGRET and summarize the results on the calculations of the evolution and luminosity function of these sources. Of the large number of possible origins of extragalactic diffuse gamma-ray…

Astrophysics · Physics 2009-10-31 R. Mukherjee , J. Chiang

Galactic radio transients (GRTs) are mysterious short-lived (~days to months) radio transients that are quiet at all other wavelengths. Until now, roughly half a dozen such sources have been reported, predominantly towards the Galactic…

We present the results of radio searches for pulsars within unidentified EGRET source error boxes. Using the Parkes multibeam system, we have surveyed 56 sources at Galactic latitudes |b| > 5 deg which do not appear to be associated with…

We present a catalog of 290 "winged" or X-shaped radio galaxies (XRGs) extracted from the latest (2014 December 17) data release of the "Very Large Array Faint Images of the Radio Sky at Twenty centimeter." We have combined these radio…

High Energy Astrophysical Phenomena · Physics 2020-07-23 Xiaolong Yang , Ravi Joshi , Gopal-Krishna , Tao An , Luis C. Ho , Paul J. Wiita , Xiang Liu , Jun Yang , Ran Wang , Xuebing Wu , Xiaofeng Yang

We present a correlative study between all unidentified EGRET sources at low Galactic latitudes and the newly discovered pulsars in the released portion of the Parkes multibeam radio survey. We note 14 positional coincidences: eight of…

Astrophysics · Physics 2009-11-07 Diego F. Torres , Yousaf M. Butt , Fernando Camilo

Radio pulsar PSR J1028-5819 was recently discovered in a high-frequency search (at 3.1 GHz)in the error circle of the EGRET source 3EG J1027-5817. The spin-down power of this young pulsar is great enough to make it very likely the…

High Energy Astrophysical Phenomena · Physics 2011-02-11 LAT Collaboration