Related papers: Discovery and identification of two gamma-ray blaz…

Discovery of a non-blazar gamma-ray transient near the Galactic plane: GRO J1838-04

We report the discovery of a remarkable gamma-ray transient source near the Galactic plane, GRO J1838-04. This source was serendipitously discovered by EGRET in June 1995 with a peak intensity of 4 E(-6) ph/cm/cm/s (for photon energies…

Astrophysics · Physics 2009-10-30 M. Tavani , R. Mukherjee , J. R. Mattox , J. Halpern , D. J. Thompson , G. Kanbach , W. Hermsen , S. N. Zhang , R. S. Foster

High energy blazars spectroscopy with X-Shooter on the VLT

We present results of observations in the UV to near-IR range for eight blazars, three of which have been recently discovered at Very High Energies (VHE) and five appearing as interesting candidates for VHE {\gamma}-ray detection. We focus…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Santiago Pita , Paolo Goldoni , Catherine Boisson , Yvonne Becherini , Lucie Gérard , Jean-Philippe Lenain , Michael Punch

Constraining the redshift of BL Lac VER J0521+211

Observation of several very high energy (VHE) flaring events of the BL Lac object VER J0521+211 were reported by the VERITAS and MAGIC collaborations between 2009 and 2014. The redshift of this source is uncertain and several analysis have…

High Energy Astrophysical Phenomena · Physics 2023-05-24 Sarira Sahu , B. Medina-Carrillo , G. Sánchez-Colón , Subhash Rajpoot

Discovery of a new Soft Gamma Repeater: SGR J0418+5729

On 2009 June 5, the Gamma-ray Burst Monitor (GBM) onboard the Fermi Gamma-ray Space Telescope triggered on two short, and relatively dim bursts with spectral properties similar to Soft Gamma Repeater (SGR) bursts. Independent localizations…

High Energy Astrophysical Phenomena · Physics 2015-05-14 A. J. van der Horst , V. Connaughton , C. Kouveliotou , E. Gogus , Y. Kaneko , S. Wachter , M. S. Briggs , J. Granot , E. Ramirez-Ruiz , P. M. Woods , R. L. Aptekar , S. D. Barthelmy , J. R. Cummings , M. H. Finger , D. D. Frederiks , N. Gehrels , C. R. Gelino , D. M. Gelino , S. Golenetskii , K. Hurley , H. A. Krimm , E. P. Mazets , J. E. McEnery , C. A. Meegan , P. P. Oleynik , D. M. Palmer , V. D. Pal'shin , A. Pe'er , D. Svinkin , M. V. Ulanov , M. van der Klis , A. von Kienlin , A. L. Watts , C. A. Wilson-Hodge

Multiwavelength observation of a candidate pulsar halo LHAASO J0621+3755 and the first X-ray detection of PSR J0622+3749

Pulsar halos are regions around middle-aged pulsars extending out to tens of parsecs. The large extent of the halos and well-defined central cosmic-ray accelerators make this new class of Galactic sources an ideal laboratory for studying…

High Energy Astrophysical Phenomena · Physics 2025-04-04 C. B. Adams , A. Archer , P. Bangale , J. T. Bartkoske , W. Benbow , J. H. Buckley , Y. Chen , J. L. Christiansen , A. J. Chromey , A. Duerr , M. Errando , M. Escobar Godoy , A. Falcone , S. Feldman , Q. Feng , L. Fortson , A. Furniss , W. Hanlon , O. Hervet , C. E. Hinrichs , J. Holder , T. B. Humensky , W. Jin , M. N. Johnson , P. Kaaret , M. Kertzman , M. Kherlakian , D. Kieda , T. K. Kleiner , N. Korzoun , F. Krennrich , S. Kumar , S. Kundu , M. J. Lang , M. Lundy , G. Maier , M. J. Millard , J. Millis , C. L. Mooney , P. Moriarty , R. Mukherjee , W. Ning , R. A. Ong , A. Pandey , M. Pohl , E. Pueschel , J. Quinn , P. L. Rabinowitz , K. Ragan , P. T. Reynolds , D. Ribeiro , L. Rizk , E. Roache , I. Sadeh , L. Saha , G. H. Sembroski , R. Shang , M. Splettstoesser , D. Tak , A. K. Talluri , J. V. Tucci , J. Valverde , D. A. Williams , S. L. Wong , J. Woo , J. Kwong , K. Mori , C. J. Hailey , S. Safi-Harb , S. Zhang , N. Tsuji , S. Manconi , F. Donato , M. Di Mauro

Recent Results from the VERITAS Collaboration

A decade after the discovery of TeV gamma-rays from the blazar Mrk 421 (Punch et al. 1992), the list of TeV blazars has increased to five BL Lac objects: Mrk 421 (Punch et al. 1992; Petry et al. 1996; Piron et al. 2001), Mrk 501 (Quinn et…

Astrophysics · Physics 2007-05-23 F. Krennrich , I. H. Bond , S. M. Bradbury , J. H. Buckley , D. A. Carter-Lewis , W. Cui , I. de la Calle Perez , A. Falcone , D. J. Fegan , S. J. Fegan , J. P. Finley , J. A. Gaidos , K. Gibbs , G. H. Gillanders , T. A. Hall , A. M. Hillas , J. Holder , D. Horan , M. Jordan , M. Kertzman , D. Kieda , J. Kildea , J. Knapp , K. Kosack , M. J. Lang , S. LeBohec , P. Moriarty , D. Muller , R. A. Ong , R. Pallassini , D. Petry , J. Quinn , P. T. Reynolds , H. J. Rose , G. H. Sembroski , S. P. Swordy , V. V. Vassiliev , S. P. Wakely , T. C. Weekes

VERITAS detection of $\gamma$-ray flaring activity from the BL Lac object 1ES 1727+502 during bright moonlight observations

During moonlit nights, observations with ground-based Cherenkov telescopes at very high energies (VHE, $E>100$ GeV) are constrained since the photomultiplier tubes (PMTs) in the telescope camera are extremely sensitive to the background…

High Energy Astrophysical Phenomena · Physics 2015-08-06 S. Archambault , A. Archer , M. Beilicke , W. Benbow , R. Bird , J. Biteau , A. Bouvier , V. Bugaev , J. V Cardenzana , M. Cerruti , X. Chen , L. Ciupik , M. P. Connolly , W. Cui , H. J. Dickinson , J. Dumm , J. D. Eisch , M. Errando , A. Falcone , Q. Feng , J. P. Finley , H. Fleischhack , P. Fortin , L. Fortson , A. Furniss , G. H. Gillanders , S. Griffin , S. T. Griffiths , J. Grube , G. Gyuk , N. Håkansson , D. Hanna , J. Holder , T. B. Humensky , C. A. Johnson , P. Kaaret , P. Kar , M. Kertzman , Y. Khassen , D. Kieda , M. Krause , F. Krennrich , S. Kumar , M. J. Lang , G. Maier , S. McArthur , A. McCann , K. Meagher , J. Millis , P. Moriarty , R. Mukherjee , D. Nieto , A. O'Faoláin de Bhróithe , R. A. Ong , A. N. Otte , N. Park , M. Pohl , A. Popkow , H. Prokoph , E. Pueschel , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , G. T. Richards , E. Roache , M. Santander , G. H. Sembroski , K. Shahinyan , A. W. Smith , D. Staszak , I. Telezhinsky , J. V. Tucci , J. Tyler , A. Varlotta , S. Vincent , S. P. Wakely , A. Weinstein , R. Welsing , A. Wilhelm , D. A. Williams , B. Zitzer , Z. D. Hughes

J16021+3326: New Multi-Frequency Observations of a Complex Source

We present multifrequency Very Long Baseline Array (VLBA) observations of J16021+3326. These observations, along with variability data obtained from the Owens Valley Radio Observatory (OVRO) candidate gamma-ray blazar monitoring program,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 S. E. Tremblay , G. B. Taylor , J. L. Richards , A. C. S. Readhead , J. F. Helmboldt , R. W. Romani , S. E. Healey

Discovery of Variability in the Very High Energy Gamma-Ray Emission of 1ES 1218+304 with VERITAS

We present results from an intensive VERITAS monitoring campaign of the high-frequency peaked BL Lac object 1ES 1218+304 in 2008/2009. Although 1ES 1218+304 was detected previously by MAGIC and VERITAS at a persistent level of ~6% of the…

High Energy Astrophysical Phenomena · Physics 2010-01-18 The VERITAS Collaboration , V. A. Acciari , E. Aliu , M. Beilicke , W. Benbow , D. Boltuch , M. Böttcher , S. M. Bradbury , V. Bugaev , K. Byrum , A. Cesarini , L. Ciupik , P. Cogan , W. Cui , R. Dickherber , C. Duke , A. Falcone , J. P. Finley , G. Finnegan , L. Fortson , A. Furniss , N. Galante , D. Gall , K. Gibbs , R. Guenette , G. H. Gillanders , S. Godambe , J. Grube , D. Hanna , C. M. Hui , T. B. Humensky , A. Imran , P. Kaaret , N. Karlsson , M. Kertzman , D. Kieda , H. Krawczynski , F. Krennrich , M. J. Lang , S. LeBohec , G. Maier , S. McArthur , A. McCann , P. Moriarty , T. Nagai , R. A. Ong , A. N. Otte , D. Pandel , J. S. Perkins , A. Pichel , M. Pohl , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , E. Roache , H. J. Rose , M. Schroedter , G. H. Sembroski , A. W. Smith , D. Steele , S. P. Swordy , M. Theiling , S. Thibadeau , V. V. Vassiliev , S. Vincent , S. P. Wakely , T. C. Weekes , A. Weinstein , T. Weisgarber , D. A. Williams

VERITAS highlights of observations and results

Located in southern Arizona, VERITAS is amongst the most sensitive detectors for astrophysical very high energy (VHE; E>100 GeV) gamma rays and has been operational since April 2007. We highlight some recent results from VERITAS…

High Energy Astrophysical Phenomena · Physics 2022-12-21 S. R. Patel

Fermi LAT detection of two high Galactic latitude gamma-ray sources, Fermi J1049.7+0435 and J1103.2+1145

During a search for gamma-ray emission from NGC 3628 (Arp 317), two new unidentified gamma-ray sources, Fermi J1049.7+0435 and J1103.2+1145 have been discovered \cite{ATel}. The detections are made in data from the Large Area Telescope…

High Energy Astrophysical Phenomena · Physics 2015-02-10 Masaki Nishimichi , Takeshi Okuda , Masaki Mori , Philip G. Edwards , Jamie Stevens

Chandra Imaging of the Gamma-Ray Source GeV J1809-2327

We report on Chandra imaging observations of the Galactic Unidentified $\gamma$-ray source GEV J1809-2327, comparing the X-ray images with new VLA 1.46 GHz and 4.86 GHz maps. The X-ray images reveal a point source connected to a non-thermal…

Astrophysics · Physics 2016-08-30 Timothy M. Braje , Roger W. Romani , Mallory S. E. Roberts , Nobuyuki Kawai

VERITAS Observations of Six Bright, Hard-Spectrum Fermi-LAT Blazars

We report on VERITAS very-high-energy (VHE; E>100 GeV) observations of six blazars selected from the Fermi Large Area Telescope First Source Catalog (1FGL). The gamma-ray emission from 1FGL sources was extrapolated up to the VHE band,…

High Energy Astrophysical Phenomena · Physics 2015-06-11 E. Aliu , S. Archambault , T. Arlen , T. Aune , M. Beilicke , W. Benbow , M. Bottcher , A. Bouvier , J. H. Buckley , V. Bugaev , A. Cesarini , L. Ciupik , E. Collins-Hughes , M. P. Connolly , W. Cui , R. Dickherber , C. Duke , J. Dumm , M. Errando , A. Falcone , S. Federici , Q. Feng , J. P. Finley , G. Finnegan , L. Fortson , A. Furniss , N. Galante , D. Gall , S. Godambe , S. Griffin , J. Grube , G. Gyuk , D. Hanna , J. Holder , H. Huan , P. Kaaret , N. Karlsson , Y. Khassen , D. Kieda , H. Krawczynski , F. Krennrich , K. Lee , A. S Madhavan , G. Maier , P. Majumdar , S. McArthur , A. McCann , P. Moriarty , R. Mukherjee , T. Nelson , A. O'Faolain de Bhroithe , R. A. Ong , M. Orr , A. N. Otte , N. Park , J. S. Perkins , A. Pichel , M. Pohl , H. Prokoph , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , E. Roache , D. B. Saxon , G. H. Sembroski , D. Staszak , I. Telezhinsky , G. Tesic , M. Theiling , S. Thibadeau , K. Tsurusaki , A. Varlotta , V. V. Vassiliev , S. Vincent , M. Vivier , S. P. Wakely , T. C. Weekes , A. Weinstein , R. Welsing , D. A. Williams , B. Zitzer , P. Fortin , D. Horan , M. Fumagalli , K. Kaplan , J. X. Prochaska

Multiwavelength Study Of Two Unidentified Gamma-ray Sources

Most counterparts of the identified low-latitude gamma-ray sources are Isolated Neutron Stars (INSs). They are characterized by an extremely high value of the X/optical flux ratio, therefore a systematic X-ray/optical coverage of the fields…

Astrophysics · Physics 2017-09-06 Nicola La Palombara , Patrizia Caraveo , Roberto Mignani , Evanthia Hatziminaoglou , Giovanni F. Bignami , Mischa Schirmer

Gamma rays from the quasar PKS 1441+25: story of an escape

Outbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints on the diffuse radiation fields that fill the Universe. The detection of significant emission above 100 GeV from a distant…

High Energy Astrophysical Phenomena · Physics 2015-12-23 A. U. Abeysekara , S. Archambault , A. Archer , T. Aune , A. Barnacka , W. Benbow , R. Bird , J. Biteau , J. H. Buckley , V. Bugaev , J. V Cardenzana , M. Cerruti , X. Chen , J. L. Christiansen , L. Ciupik , M. P. Connolly , P. Coppi , W. Cui , H. J. Dickinson , J. Dumm , J. D. Eisch , M. Errando , A. Falcone , Q. Feng , J. P. Finley , H. Fleischhack , A. Flinders , P. Fortin , L. Fortson , A. Furniss , G. H. Gillanders , S. Griffin , J. Grube , G. Gyuk , M. Hütten , N. Håkansson , D. Hanna , J. Holder , T. B. Humensky , C. A. Johnson , P. Kaaret , P. Kar , N. Kelley-Hoskins , Y. Khassen , D. Kieda , M. Krause , F. Krennrich , S. Kumar , M. J. Lang , G. Maier , S. McArthur , A. McCann , K. Meagher , P. Moriarty , R. Mukherjee , D. Nieto , A. O'Faoláin de Bhróithe , R. A. Ong , A. N. Otte , N. Park , J. S. Perkins , A. Petrashyk , M. Pohl , A. Popkow , E. Pueschel , J. Quinn , K. Ragan , G. Ratliff , P. T. Reynolds , G. T. Richards , E. Roache , J. Rousselle , M. Santander , G. H. Sembroski , K. Shahinyan , A. W. Smith , D. Staszak , I. Telezhinsky , N. W. Todd , J. V. Tucci , J. Tyler , V. V. Vassiliev , S. Vincent , S. P. Wakely , O. M. Weiner , A. Weinstein , A. Wilhelm , D. A. Williams , B. Zitzer , P. S. Smith , T. W. -S. Holoien , J. L. Prieto , C. S. Kochanek , K. Z. Stanek , B. Shappee , T. Hovatta , W. Max-Moerbeck , T. J. Pearson , R. A. Reeves , J. L. Richards , A. C. S. Readhead , G. M. Madejski , S. G. Djorgovski , A. J. Drake , M. J. Graham , A. Mahabal

VERITAS Observations of Blazars

The VERITAS array of four 12-m diameter imaging atmospheric-Cherenkov telescopes in southern Arizona is used to study very high energy (VHE; E>100 GeV) gamma-ray emission from astrophysical objects. VERITAS is currently the most sensitive…

High Energy Astrophysical Phenomena · Physics 2010-01-07 Wystan Benbow

Very-High-Energy $\gamma$-Ray Observations of the Blazar 1ES 2344+514 with VERITAS

We present very-high-energy $\gamma$-ray observations of the BL Lac object 1ES 2344+514 taken by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) between 2007 and 2015. 1ES 2344+514 is detected with a statistical…

High Energy Astrophysical Phenomena · Physics 2017-08-10 C. Allen , S. Archambault , A. Archer , W. Benbow , R. Bird , E. Bourbeau , R. Brose , M. Buchovecky , J. H. Buckley , V. Bugaev , J. V Cardenzana , M. Cerruti , X. Chen , J. L. Christiansen , M. P. Connolly , W. Cui , M. K. Daniel , J. D. Eisch , A. Falcone , Q. Feng , M. Fernandez-Alonso , J. P. Finley , H. Fleischhack , A. Flinders , L. Fortson , A. Furniss , G. H. Gillanders , S. Griffin , J. Grube , M. Hütten , N. Håkansson , D. Hanna , O. Hervet , J. Holder , G. Hughes , T. B. Humensky , C. A. Johnson , P. Kaaret , P. Kar , N. Kelley-Hoskins , M. Kertzman , D. Kieda , M. Krause , F. Krennrich , S. Kumar , M. J. Lang , G. Maier , S. McArthur , A. McCann , K. Meagher , P. Moriarty , R. Mukherjee , T. Nguyen , D. Nieto , S. O'Brien , A. O'Faoláin de Bhróithe , R. A. Ong , A. N. Otte , N. Park , A. Petrashyk , A. Pichel , M. Pohl , A. Popkow , E. Pueschel , J. Quinn , K. Ragan , P. T. Reynolds , G. T. Richards , E. Roache , A. C. Rovero , C. Rulten , I. Sadeh , M. Santander , G. H. Sembroski , K. Shahinyan , I. Telezhinsky , J. V. Tucci , J. Tyler , S. P. Wakely , A. Weinstein , A. Wilhelm , D. A. Williams

Chandra Observations of High Energy X-ray Sources Discovered by INTEGRAL

The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has detected in excess of 1000 sources in the ~20-100 keV band during its surveys of the sky over the past 17 years. We obtained 5 ks observations of 15 unclassified…

High Energy Astrophysical Phenomena · Physics 2020-02-05 John A. Tomsick , Arash Bodaghee , Sylvain Chaty , Maica Clavel , Francesca M. Fornasini , Jeremy Hare , Roman Krivonos , Farid Rahoui , Jerome Rodriguez

Discovery of VHE Gamma-ray Emission from the Starburst Galaxy M82

The galaxy M82 has long been considered a promising target for VHE gamma-ray observations because of the compact starburst region in its core. Theoretical predictions have suggested it should be detectable by ground-based imaging Cherenkov…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Niklas Karlsson

Fermi LAT detection of pulsed gamma-rays from the Vela-like pulsars PSR J1048-5832 and PSR J2229+6114

We report the detection of gamma-ray pulsations (> 0.1 GeV) from PSR J2229+6114 and PSR J1048-5832, the latter having been detected as a low-significance pulsar by EGRET. Data in the gamma-ray band were acquired by the Large Area Telescope…

High Energy Astrophysical Phenomena · Physics 2009-12-04 Fermi LAT collaboration , Fermi Pulsar Timing Consortium