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Related papers: A Search for Candidate TeV Emitters in the High-la…

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We report the results from our analysis of a large set of archival data acquired with the X-ray telescope (XRT) onboard Swift, covering the sky region surrounding objects from the first Fermi Large Area Telescope (LAT) catalogue of…

High Energy Astrophysical Phenomena · Physics 2015-09-16 R. Landi , L. Bassani , J. B. Stephen , N. Masetti , A. Malizia , P. Ubertini

High energy observations of extreme BL Lac objects, such as 1ES 0229+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 2015-06-25 Giacomo Bonnoli , Fabrizio Tavecchio , Gabriele Ghisellini , Tullia Sbarrato

M87 is a giant radio galaxy located in the Virgo Cluster, known to be a very high energy (VHE) gamma-ray source. As radio galaxies are considered the misaligned low-redshift counterparts of blazars, they are excellent laboratories for…

High Energy Astrophysical Phenomena · Physics 2021-08-03 Fernando Ureña-Mena , Alberto Carramiñana , Anna Lia Longinotti , Daniel Rosa-González

Very high-energy (VHE) detected flat-spectrum radio quasars (FSRQs) are relatively few despite being the most persistent bright MeV-GeV sources. Focusing on VHE emission, we investigated the spectral and temporal properties of VHE-detected…

High Energy Astrophysical Phenomena · Physics 2025-12-03 Megha , Pankaj Kushwaha

There are a total of 1451 gamma-ray emitting objects in the Fermi Large Area Telescope First Source Catalogue. The point source location accuracy of typically a few arcminutes has allowed the counterparts for many of these sources to be…

High Energy Astrophysical Phenomena · Physics 2015-05-18 J. B. Stephen , L. Bassani , R. Landi , A. Malizia , V. Sguera , A. Bazzano , N. Masetti

We investigate the spectroscopic optical properties of gamma-ray sources detected with high significance above 50 GeV in the Third Catalog of Hard Fermi-LAT Sources (3FHL) and that are good candidates as TeV emitters. We focus on the 91…

Astrophysics of Galaxies · Physics 2020-07-08 Simona Paiano , Renato Falomo , Aldo Treves , Riccardo Scarpa

Measuring the diffuse Galactic gamma-ray flux in the TeV range is difficult for ground-based gamma-ray telescopes because of the residual cosmic-ray background, which is higher than the gamma-ray flux by several orders of magnitude. Its…

High Energy Astrophysical Phenomena · Physics 2020-01-22 A. Neronov , D. V. Semikoz

A list of 205 gamma-ray strong objects was reported recently as a result of a 3-month integration with the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope. We attempted identification of these objects, cross-correlating…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Y. Y. Kovalev

The {\it Fermi} Large Area Telescope (LAT) has been routinely gathering science data since August 2008, surveying the full sky every three hours. The first Fermi-LAT catalog of sources detected above 10 GeV (1FHL) relied on three years of…

High Energy Astrophysical Phenomena · Physics 2019-08-14 M. Ajello , A. Domínguez , D. Gasparrini , S. Cutini

Observations of distant gamma-ray sources are hindered by the presence of the extragalactic background light (EBL). In order to understand the physical processes that result in the observed spectrum of sources, it is imperative that a good…

High Energy Astrophysical Phenomena · Physics 2017-06-01 Thomas Armstrong , Anthony M. Brown , Paula M. Chadwick

During its first 2 years of mission the Fermi-LAT instrument discovered more than 1,800 gamma-ray sources in the 100 MeV to 100 GeV range. Despite the application of advanced techniques to identify and associate the Fermi-LAT sources with…

High Energy Astrophysical Phenomena · Physics 2016-03-02 David Salvetti

This work intends to provide a brief summary of some of the Galactic science issues for the next generation of very high energy (VHE) instruments. The latter is here generically understood, as an instrument or set of instruments providing…

Astrophysics · Physics 2009-11-13 Diego F. Torres

We present a catalog of sources detected above 50 GeV by the {\it Fermi}-Large Area Telescope (LAT) in 80 months of data. The newly delivered Pass 8 event-level analysis allows the detection and characterization of sources in the 50 GeV--2…

High Energy Astrophysical Phenomena · Physics 2016-03-23 LAT Collaboration

The large majority of extragalactic very high energy (VHE; E>100 GeV) sources belongs to the class of active galactic nuclei (AGN), in particular the BL Lac sub-class. AGNs are characterized by an extremely bright and compact emission…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-15 Martin Raue , Lukasz Stawarz , Daniel Mazin , Pierre Colin , Michelle Hui , Matthias Beilicke , Craig Walker

Our understanding of blazars has been greatly increased in recent years by extensive multi-wavelength observations, particularly in the radio, X-ray and gamma-ray regions. Over the past decade the Whipple 10m telescope has contributed to…

Astrophysics · Physics 2010-11-24 I. de la Calle Perez , the VERITAS Collaboration

With almost 15 years of data taken by the Large Area Telescope (LAT) onboard the Fermi satellite we discovered an extended source of GeV emission in the region of the very-high-energy (TeV) source 1LHAASO J1945+2424. This TeV source is more…

High Energy Astrophysical Phenomena · Physics 2023-12-05 Miguel Araya , J. A. Álvarez-Quesada

In recent years, blazar surveys at radio and X-ray energies have greatly increased our understanding of this type of active galaxy. The combination of multi-wavelength data has shown that blazars follow a well defined sequence in terms of…

Astrophysics · Physics 2007-05-23 I. de la Calle Perez

Analysis of data from the Fermi Large Area Telescope (LAT) in the region of the supernova remnant G78.2+2.1 reveals an excess at the position of the TeV source VER J2019+407. The GeV source is extended with a hard spectrum and it is likely…

High Energy Astrophysical Phenomena · Physics 2017-01-10 Miguel Araya , Nissim Fraija

Flat spectrum radio quasars (FSRQs) have been detected at TeV energies by ground-based atmospheric Cherenkov telescopes mainly during flaring states. VERITAS is carrying out the first systematic and unbiased search for TeV emissions from a…

High Energy Astrophysical Phenomena · Physics 2021-08-23 Sonal R. Patel

This paper reports the results from three targeted searches of Milagro TeV sky maps: two extragalactic point source lists and one pulsar source list. The first extragalactic candidate list consists of 709 candidates selected from the…

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