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As a critical part of the Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry (TANAMI) program, in November 2007 the Australia Telescope Compact Array (ATCA) started monitoring the radio spectra of a sample of…

High Energy Astrophysical Phenomena · Physics 2012-05-14 J. Stevens , P. G. Edwards , R. Ojha , M. Kadler , F. Hungwe , M. Dutka , S. Tingay , J. P. Macquart , A. Moin , J. Lovell , J. Blanchard

The Fermi Large Area Telescope revealed that the extragalactic gamma-ray sky is dominated by blazars, active galactic nuclei (AGN) whose jet is seen at very small angle to the line of sight. To associate and then classify the gamma-ray…

Astrophysics of Galaxies · Physics 2018-05-09 K. É. Gabányi , S. Frey , T. An

We present a catalogue of local ($z<0.1$) galaxies that contain faint AGN. We select these objects by identifying galaxies that exhibit a significant excess in their radio luminosities, compared to what is expected from the observed levels…

Astrophysics of Galaxies · Physics 2018-06-06 E. K. Lofthouse , S. Kaviraj , D. J. B. Smith , M. J. Hardcastle

We present some first results on the variability, polarization and general properties of radio sources selected in a blind survey at 20 GHz, the highest frequency at which a sensitive radio survey has been carried out over a large area of…

We report on the results of X-ray and radio follow-up observations of two GeV gamma-ray sources 2FGL J0923.5+1508 and 2FGL J1502.1+5548, selected as candidates for high-redshift blazars from unassociated sources in the {\it Fermi} Large…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Y. Takahashi , J. Kataoka , K. Niinuma , M. Honma , Y. Inoue , T. Totani , S. Inoue , T. Nakamori , K. Maeda

In this letter we present the result of the cross correlation between the 4th INTEGRAL/IBIS soft gamma-ray catalog, in the range 20-100 keV, and the Fermi LAT bright source list of objects emitting in the 100 MeV - 100 GeV range. The main…

High Energy Astrophysical Phenomena · Physics 2014-11-20 P. Ubertini , V. Sguera , J. B. Stephen , L. Bassani , A. Bazzano , A. J. Bird

An analytic relation between the statistics of photons in pixels and the number counts of multi-photon point sources is used to constrain the distribution of gamma-ray point sources below the Fermi detection limit at energies above 1 GeV…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-06 Dmitry Malyshev , David W. Hogg

We have made the first detailed study of the high-frequency radio-source population in the local universe, using a sample of 202 radio sources from the Australia Telescope 20 GHz (AT20G) survey identified with galaxies from the 6dF Galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Elaine M. Sadler , Ronald D. Ekers , Elizabeth Mahony , Tom Mauch , Tara Murphy

We present a systematic reassessment of 5,062 high-Galactic latitude gamma-ray sources from the Fermi-LAT 4FGL-DR4 catalog using Firmamento, a web-based platform for multi-frequency source discovery and analysis. Our goal is to provide an…

We analyze the angular power spectrum (APS) of the unresolved gamma-ray background (UGRB) emission and combine it with the measured properties of the resolved gamma-ray sources of the Fermi-LAT 4FGL catalog. Our goals are to dissect the…

High Energy Astrophysical Phenomena · Physics 2023-07-07 Michael Korsmeier , Elena Pinetti , Michela Negro , Marco Regis , Nicolao Fornengo

A large sample of known and likely gamma-ray blazars has been monitored twice per week since late 2007 at 15 GHz with the Owens Valley Radio Observatory (OVRO) 40-meter Telescope. The sample contains about 1700 sources, including the…

High Energy Astrophysical Phenomena · Physics 2012-05-03 W. Max-Moerbeck , J. L. Richards , V. Pavlidou , T. Hovatta , O. G. King , T. J. Pearson , A. C. S. Readhead , R. Reeves , M. C. Shepherd

Building on our previous cross-correlation analysis (Xia et al. 2011) between the isotropic gamma-ray background (IGRB) and different tracers of the large-scale structure of the universe, we update our results using 60-months of data from…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-24 Jun-Qing Xia , Alessandro Cuoco , Enzo Branchini , Matteo Viel

B2013+370 and B2023+336 are two blazars at low-galactic latitude that were previously proposed to be the counterparts for the EGRET unidentified sources, 3EG J2016+3657 and 3EG J2027+3429. Gamma-ray emission associated with the EGRET…

High Energy Astrophysical Phenomena · Physics 2015-06-03 E. Kara , M. Errando , W. Max-Moerbeck , E. Aliu , M. Bottcher , P. Fortin , J. P. Halpern , R. Mukherjee , A. C. S. Readhead , J. L. Richards

In its first four years of operation, the Fermi Large Area Telescope (LAT) detected 3033 $\gamma$-ray emitting sources. In the Fermi-LAT Third Source Catalogue (3FGL) about 50% of the sources have no clear association with a likely…

High Energy Astrophysical Phenomena · Physics 2017-07-19 David Salvetti , Graziano Chiaro , Giovanni La Mura , David J. Thompson

BL Lac Objects (BL Lacs) and Flat Spectrum Radio Quasars (FSRQs) are radio-loud active galaxies (AGNs) whose jets are seen at a small viewing angle (blazars), while Misaligned Active Galactic Nuclei (MAGNs) are mainly radiogalaxies of type…

High Energy Astrophysical Phenomena · Physics 2018-08-20 G. Chiaro , M. Meyer , N. Alvarez Crespo , R. J. Britto , J. P. Marais , B. van Soelen , D. Salvetti , G. La Mura , D. J Thompson

This is the first of a series of papers aimed at characterizing the populations detected in the high-latitude sky of the {\it Fermi}-LAT survey. In this work we focus on the intrinsic spectral and flux properties of the source sample. We…

Cosmology and Nongalactic Astrophysics · Physics 2010-09-02 LAT Collaboration

The advent of new all-sky radio surveys such as the VLA Sky Survey (VLASS) and the Rapid ASKAP Continuum Survey (RACS), performed with the latest generation radio telescopes, is opening new possibilities on the classification and study of…

High Energy Astrophysical Phenomena · Physics 2022-04-06 G. Bruni , L. Bassani , M. Persic , Y. Rephaeli , A. Malizia , M. Molina , M. Fiocchi , R. Ricci , M. H. Wieringa , M. Giroletti , F. Panessa , A. Bazzano , P. Ubertini

We considered the fourth catalog of gamma-ray point sources produced by the Fermi Large Area Telescope (LAT) and selected only jetted active galactic nuclei (AGN) or sources with no specific classification, but with a low-frequency…

We present the fourth Fermi Large Area Telescope catalog (4FGL) of gamma-ray sources. Based on the first eight years of science data from the Fermi Gamma-ray Space Telescope mission in the energy range from 50 MeV to 1 TeV, it is the…

High Energy Astrophysical Phenomena · Physics 2020-05-27 LAT collaboration

In the framework of the TANAMI multi-wavelength and VLBI monitoring, we study the evolution of the parsec-scale radio emission in radio galaxies in the southern hemisphere and their relationship to the $\gamma$-ray properties. In this first…

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