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Despite the plethora of deep (sub-mJy) radio surveys there remains considerable doubt as to the exact nature of the galaxies contributing to the source counts. Current evidence suggests that starformation in moderately luminous 'normal'…

Astrophysics · Physics 2009-11-11 Nick Seymour , Derek Moss , Ian McHardy , Katherine Gunn , Mat Page , Nic Loaring , Tom Dwelly

We provide our estimates of the intensity of the gamma-ray emission with an energy near 0.1 TeV generated in inrergalactic space in the interactions of cosmic rays with background emissions. We assume that the cosmic ray sources are…

High Energy Astrophysical Phenomena · Physics 2017-08-30 A. V. Uryson

High-precision interferometric observations of six early-type main sequence stars known to harbour cold debris discs have been obtained in the near-infrared K band with the FLUOR instrument at the CHARA Array. The measured squared…

We report the detection of high-energy gamma-ray signal towards the young star-forming region, W40. Using 10-year Pass 8 data from the Fermi Large Area Telescope (Fermi-LAT), we extracted an extended gamma-ray excess region with a…

High Energy Astrophysical Phenomena · Physics 2020-07-22 Xiao-Na Sun , Rui-Zhi Yang , Yun-Feng Liang , Fang-Kun Peng , Hai-Ming Zhang , Xiang-Yu Wang , Felix Aharonian

We study the correlation between the gamma-ray flux F_g, averaged over the first 11 months of Fermi survey and integrated above 100 MeV, and the radio flux density (F_r at 20 GHz) of Fermi sources associated with a radio counterpart in the…

High Energy Astrophysical Phenomena · Physics 2015-05-19 G. Ghirlanda , G. Ghisellini , F. Tavecchio , L. Foschini , G. Bonnoli

Extremely powerful astrophysical electromagnetic (EM) system could be possible source of high-frequency gravitational waves (HFGWs). Here based on properties of magnetars and gamma-ray bursts (GRBs), we address "Gamma-HFGWs" (with very…

General Relativity and Quantum Cosmology · Physics 2024-04-04 Hao Wen , Fangyu Li , Jin Li , Zhenyun Fang , Andrew Beckwith

We search for transient gamma-ray emission in the energy range from 0.1-10 GeV using data from the Fermi-LAT telescope in coincidence with magnetar flares. For our analysis, we look for coincidence with 15 distinct flares from 11 magnetars…

High Energy Astrophysical Phenomena · Physics 2025-07-17 Vyaas Ramakrishnan , Shantanu Desai

Galactic cosmic ray (CRs) sources, classically proposed to be Supernova Remnants (SNRs), must meet the energetic particle content required by direct measurements of high energy CRs. Indirect gamma-ray measurements of SNRs with the Fermi…

High Energy Astrophysical Phenomena · Physics 2019-08-13 T. J. Brandt , F. Acero , F. de Palma , J. W. Hewitt , M. Renaud

We present observations of HESS J1640-465 with the Fermi-LAT. The source is detected with high confidence as an emitter of high-energy gamma-rays. The spectrum lacks any evidence for the characteristic cutoff associated with emission from…

High Energy Astrophysical Phenomena · Physics 2015-05-18 P. Slane , D. Castro , S. Funk , Y. Uchiyama , A. Lemiere , J. D. Gelfand , M. Lemoine-Goumard

Many gamma-ray bursts (GRBs) have been observed from radio wavelengths, and a few at very-high energies (VHEs, > 100GeV). The HAWC gamma-ray observatory is well suited to study transient phenomena at VHEs due to its large field of view and…

We present the analysis of Fermi Large Area Telescope (LAT) $\gamma$-ray observations of HB~21 (G89.0+4.7). We detect significant $\gamma$-ray emission associated with the remnant: the flux >100 MeV is…

High Energy Astrophysical Phenomena · Physics 2015-06-17 G. Pivato , J. Hewitt , L. Tibaldo , F. Acero , J. Ballet , T. J. Brandt , F. de Palma , F. Giordano , G. H. Janssen , G. Johannesson , D. A. Smith

This is the first report of Fermi Gamma-ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope (LAT), covering 2008 July 7 -…

High Energy Astrophysical Phenomena · Physics 2012-08-27 LAT Collaboration , A. A. Abdo

Very high-energy (VHE; E > 100 GeV) gamma-rays have been detected from a wide range of astronomical objects, such as SNRs, pulsars and pulsar wind nebulae, AGN, gamma-ray binaries, molecular clouds, and possibly star-forming regions as…

High Energy Astrophysical Phenomena · Physics 2010-01-19 P. H. Thomas Tam , Stefan Wagner , Omar Tibolla , Ryan Chaves

We present a new extended gamma ray excess detected with the Fermi Satellite Large Area Telescope toward the Galactic Center that traces the morphology of infrared starlight emission. Combined with its measured spectrum, this new extended…

High Energy Astrophysical Phenomena · Physics 2015-07-13 Kevork N. Abazajian , Nicolas Canac , Shunsaku Horiuchi , Manoj Kaplinghat , Anna Kwa

We analyze new high-resolution Chandra X-ray images of the Wolf-Rayet binary system WR147. This system contains a WN8 star with an early-type companion located 0.6'' to its north, and is the only known early-type binary with a separation on…

We present an analysis of 17 years of Fermi-LAT observations of the microquasar SS~433. We detect four GeV sources in the region: a newly identified source, PS J1910+0550, located outside W50; the previously reported source J1913+0512; and…

High Energy Astrophysical Phenomena · Physics 2026-05-15 Qiwang Sun , Dmitry Khangulyan , Jiren Liu , Siming Liu

Population studies of unidentified EGRET sources suggest that there exist at least three different populations of galactic gamma-ray sources. One of these populations is formed by young objects distributed along the galactic plane with a…

Astrophysics · Physics 2009-11-10 V. Bosch-Ramon , G. E. Romero , J. M. Paredes

Among thousands of extragalactic $\gamma$-ray emitters, only a handful of distant ($z >$ 3) sources are detected. Yet, they are crucial probes shedding light on the cosmic evolution of jets of active galactic nuclei and the initial phase of…

High Energy Astrophysical Phenomena · Physics 2026-04-16 Wei Zhang , Neng-Hui Liao , Hao-Yi Huang , Hai Lei , Xiong Jiang , Ning Jiang , Zhen-Feng Sheng , Lu-Lu Fan , Ting-Gui Wang

The high sensitivity of the Fermi-LAT (Large Area Telescope) offers the first opportunity to study faint and extended GeV sources such as pulsar wind nebulae (PWNe). After one year of observation the LAT detected and identified three pulsar…

High Energy Astrophysical Phenomena · Physics 2011-01-28 The Fermi LAT Collaboration , Pulsar Timing Consortium

We investigate Wolf-Rayet (WR) stars as a source of feedback contributing to the removal of natal material in the early evolution of massive star clusters. Despite previous work suggesting that massive star clusters clear out their natal…

Astrophysics of Galaxies · Physics 2016-08-17 Kimberly R. Sokal , Kelsey E. Johnson , Remy Indebetouw , Philip Massey