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We present multi-epoch observations from the Submillimeter Array (SMA) for a sample of 171 bright blazars, 43 of which were detected by Fermi during the first three months of observations. We explore the correlation between their gamma-ray…

High Energy Astrophysical Phenomena · Physics 2010-01-07 Allison L. Strom , Aneta Siemiginowska , Mark A. Gurwell , Brandon C. Kelly

Approximately one-third of the gamma-ray sources in the third Fermi-LAT catalog are unidentified or unassociated with objects at other wavelengths. Observations with Swift-XRT have yielded possible counterparts in $\sim$30% of these source…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Amanpreet Kaur , Abraham D Falcone , Michael D Stroh , Jamie A Kennea , Elizabeth C Ferrara

We discuss a new method for unveiling the possible blazar AGN nature among the numerous population of Unassociated Gamma-ray sources (UGS) in the Fermi catalogues. Our tool relies on positional correspondence of the Fermi object with X-ray…

High Energy Astrophysical Phenomena · Physics 2017-05-31 Simona Paiano , Alberto Franceschini , Antonio Stamerra

We study the radio spectral properties of 2,094 star-forming galaxies (SFGs) by combining our early science data from the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) survey with VLA, GMRT radio data, and rich…

We present the First Cosmic Gamma-ray Horizon (1CGH) catalogue, featuring $\gamma$-ray detections above 10 GeV based on 16 years of observations with the Fermi Large Area Telescope (LAT) satellite. After carefully selecting a sample of…

High Energy Astrophysical Phenomena · Physics 2025-03-14 Bruno Arsioli , Yu-Ling Chang , Luca Ighina

We present an in-depth and systematic variability study of a sample of 20 powerful blazars, including 12 BL Lacs and 8 flat spectrum radio quasars, applying various analysis tools such as flux distribution, symmetry analysis, and time…

High Energy Astrophysical Phenomena · Physics 2020-03-18 Gopal Bhatta , Niraj Dhital

We present results of variability study of a sample of 20 powerful blazars using Fermi/LAT (0.1--300 GeV) observations. We studied decade-long observations applying various analysis tools such as flux distribution, symmetry analysis, and…

High Energy Astrophysical Phenomena · Physics 2021-07-27 Gopal Bhatta , Niraj Dhital

Based on the $\gamma$-ray data of blazars in the third EGRET catalog and radio data at 5 GHz, we studied the correlation between the radio and $\gamma$-ray luminosities using two statistical methods. The first method was the partial…

Astrophysics · Physics 2015-06-24 L. Zhang , K. S. Cheng , J. H. Fan

This paper presents a new complete and well defined sample of Flat Spectrum Radio Sources (FSRS) selected from the CLASS survey with the further constraint of a bright (mag<17.5) optical counterpart. The sample has been designed to produce…

Astrophysics · Physics 2016-01-13 M. J. M. Marcha , A. Caccianiga , I. W. A. Browne , N. Jackson

In order to determine the location of the gamma-ray emission site in blazars, we investigate the time-domain relationship between their radio and gamma-ray emission. Light-curves for the brightest detected blazars from the first 3 years of…

The Fermi/LAT telescope is an efficient blazar-detector in the MeV/GeV range. More than 1100 (900) blazars detected above 100 MeV (10 GeV) are clearly associated to BL Lacertae or Flat Spectrum Radio Quasar objects in the Fermi/LAT 3FGL…

High Energy Astrophysical Phenomena · Physics 2017-10-02 Julien Lefaucheur , Catherine Boisson , Paolo Goldoni , Santiago Pita

We present the results of a multi-frequency, time-averaged analysis of blazars included in the Candidate Gamma-ray Blazar Survey catalog. Our sample consists of 324 $\gamma$-ray detected ($\gamma$-ray loud) and 191 non $\gamma$-ray detected…

High Energy Astrophysical Phenomena · Physics 2017-12-20 Vaidehi S. Paliya , L. Marcotulli , M. Ajello , M. Joshi , S. Sahayanathan , A. R. Rao , D. Hartmann

Context. Radio halos are megaparsec-scale diffuse radio sources{ mostly} located at the centres of merging galaxy clusters. The common mechanism invoked to explain their origin is the re-acceleration of relativistic particles caused by…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-27 G. Di Gennaro , R. J. van Weeren , R. Cassano , G. Brunetti , M. Brüggen , M. Hoeft , E. Osinga , A. Botteon , V. Cuciti , F. de Gasperin , H. J. A. Röttgering , C. Tasse

The Large Area Telescope (LAT) aboard the Fermi satellite allows us to study the high-energy gamma-ray sky with unprecedented sensitivity. However, the origin of 31% of the detected gamma-ray sources remains unknown. This population of…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Hannes-S. Zechlin , Dieter Horns

Strong evidence exists for a highly significant correlation between the radio flux density and gamma-ray energy flux in blazars revealed by Fermi. However, there are central issues that need to be clarified in this field: what are the…

High Energy Astrophysical Phenomena · Physics 2019-08-15 M. Giroletti , M. Orienti , F. D'Ammando , F. Massaro , G. Tosti , R. Lico , G. Giovannini , I. Agudo , A. Alberdi , H. Bignall , M. Pandey-Pommier , A. Wolter

We report results of a multiband monitoring campaign of the flat spectrum radio quasar TXS 0536+145 at redshift 2.69. This source was detected during a very high gamma-ray activity state in 2012 March by the Large Area Telescope on board…

High Energy Astrophysical Phenomena · Physics 2015-06-22 M. Orienti , F. D'Ammando , M. Giroletti , J. Finke , M. Ajello , D. Dallacasa , T. Venturi

The Large Area Telescope (LAT) on board the \emph{Fermi} Gamma-ray Space Telescope has been continuously providing good quality survey data of the entire sky in the high energy range from 30 MeV to 500 GeV and above since August 2008. A…

High Energy Astrophysical Phenomena · Physics 2025-10-13 A. Pathania , K. K. Singh , S. K. Singh , A. Tolamatti , B. B. Singh , K. K. Yadav

Despite the fact that blazars constitute the rarest class among active galactic nuclei (AGNs) they are the largest known population of associated $\gamma$-ray sources. Many of the $\gamma$-ray objects listed in the Fermi-Large Area…

Using the Alternative Data Release of the TIFR GMRT Sky Survey (TGSS), we studied the low-frequency properties of FR0 radio galaxies, the large population of compact radio sources associated with red massive early-type galaxies revealed by…

Astrophysics of Galaxies · Physics 2019-11-20 Alessandro Capetti , Ranieri D. Baldi , Marisa Brienza , Raffaella Morganti , Gabriele Giovannini

We describe a uniform all-sky survey of bright blazars, selected primarily by their flat radio spectra, that is designed to provide a large catalog of likely gamma-ray AGN. The defined sample has 1625 targets with radio and X-ray properties…

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