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We reanalyze Fermi/LAT gamma-ray spectra of bright blazars with a higher photon statistics than in previous works and with new Pass 7 data representation. In the spectra of the brightest blazar 3C 454.3 and possibly of 4C +21.35 we detect…

High Energy Astrophysical Phenomena · Physics 2014-09-24 Boris E. Stern , Juri Poutanen

Spectra of the brightest blazars detected by the Fermi Gamma-ray Space Telescope Large Area Telescope cannot be described by a simple power law model. A much better description is obtained with a broken power law, with the break energies of…

High Energy Astrophysical Phenomena · Physics 2010-06-25 Juri Poutanen , Boris Stern

We study spectral properties of the brightest gamma-ray blazar 3C454.3 using 138 weeks of observations by the Fermi Gamma-ray Space Telescope (Fermi). We probe the behaviour of the source as a function of time at different brightness…

High Energy Astrophysical Phenomena · Physics 2012-01-09 Boris E. Stern , Juri Poutanen

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

The synergy between the Fermi-LAT and ground-based Cherenkov telescope arrays gives us the opportunity for the first time to characterize the high-energy emission from blazars over 5 decades in energy, from 100 MeV to 10 TeV. In this study,…

High Energy Astrophysical Phenomena · Physics 2015-06-12 G. D. Senturk , M. Errando , M. Boettcher , R. Mukherjee

The synergy between the Fermi-LAT and ground-based Cherenkov telescope arrays gives us the opportunity for the first time to characterize the high energy emission (100 MeV - 10 TeV) from more than 30 blazars. In this study we performed a…

High Energy Astrophysical Phenomena · Physics 2011-11-03 G. D. Senturk , M. Errando , M. Boettcher , P. Coppi , R. Mukherjee , P. Roustazadeh

The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope observatory is a pair conversion telescope sensitive to gamma-rays over more than four energy decades, between 20 MeV and more than 300 GeV. Acting in synergy with the…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Nicola Omodei

The Fermi-LAT has observed new gamma-ray flares from the blazar B0218+357 during July 2014. While no significant change in the gamma-ray spectrum has been previously observed through the flaring phase in late-2012, during this recent high…

High Energy Astrophysical Phenomena · Physics 2015-02-12 S. Buson , C. C. Cheung , S. Larsson , J. D. Scargle

We report on a detailed investigation of the gamma-ray emission from 18 broad line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope (LAT) data. We confirm the previously reported detections of 3C 120 and 3C 111 in the…

Recent detection of suborbital gamma-ray variability of Flat Spectrum Radio Quasar (FSRQ) 3C 279 by Fermi Large Area Telescope (LAT) is in severe conflict with established models of blazar emission. This paper presents the results of…

High Energy Astrophysical Phenomena · Physics 2017-12-15 Krzysztof Nalewajko

In this paper we report on the two-year-long Fermi-LAT observation of the peculiar blazar 4C +21.35 (PKS 1222+216). This source was in a quiescent state from the start of science operations of the Fermi Gamma-ray Space Telescope in 2008…

High-$z$ blazars (z $\geq 2.5$) are the most powerful class of persistent $\gamma$-ray sources in the Universe. These objects possess the highest jet powers and luminosities and have black hole masses often in excess of $10^9$ solar masses.…

High Energy Astrophysical Phenomena · Physics 2020-11-18 M. Kreter , A. Gokus , F. Krauß , M. Kadler , R. Ojha , S. Buson , J. Wilms , M. Böttcher

The Large Area Telescope (LAT) aboard the $Fermi$ spacecraft routinely observes high-energy emission from gamma-ray bursts (GRBs). Here we present the second catalog of LAT-detected GRBs, covering the first 10 years of operations, from 2008…

High Energy Astrophysical Phenomena · Physics 2019-06-28 M. Axelsson , E. Bissaldi , N. Omodei , G. Vianello

Blazars are a subclass of active galactic nuclei (AGN) having relativistic jets aligned within a few degrees of our line-of-sight and form the majority of the AGN detected in the TeV regime. The Fermi-Large Area Telescope (LAT) is a…

High Energy Astrophysical Phenomena · Physics 2023-07-04 Atreya Acharyya , Alberto C. Sadun

The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope routinely detects the highly dust-absorbed, reddened, and MeV-peaked flat spectrum radio quasar PKS 1830-211 (z=2.507). Its apparent isotropic gamma-ray luminosity…

High Energy Astrophysical Phenomena · Physics 2015-06-23 The Fermi LAT Collaboration , A. A. Abdo , M. Ackermann , M. Ajello , A. Allafort , M. A. Amin , L. Baldini , G. Barbiellini , D. Bastieri , K. Bechtol , R. Bellazzini , R. D. Blandford , E. Bonamente , A. W. Borgland , J. Bregeon , M. Brigida , R. Buehler , D. Bulmash , S. Buson , G. A. Caliandro , R. A. Cameron , P. A. Caraveo , E. Cavazzuti , C. Cecchi , E. Charles , C. C. Cheung , J. Chiang , G. Chiaro , S. Ciprini , R. Claus , J. Cohen-Tanugi , J. Conrad , R. H. D. Corbet , S. Cutini , F. D'Ammando , A. de Angelis , F. de Palma , C. D. Dermer , P. S. Drell , A. Drlica-Wagner , C. Favuzzi , J. Finke , W. B. Focke , Y. Fukazawa , P. Fusco , F. Gargano , D. Gasparrini , N. Gehrels , N. Giglietto , F. Giordano , M. Giroletti , T. Glanzman , I. A. Grenier , J. E. Grove , S. Guiriec , D. Hadasch , M. Hayashida , E. Hays , R. E. Hughes , Y. Inoue , M. S. Jackson , T. Jogler , G. Jòhannesson , A. S. Johnson , T. Kamae , J. Knödlseder , M. Kuss , J. Lande , S. Larsson , L. Latronico , F. Longo , F. Loparco , B. Lott , M. N. Lovellette , P. Lubrano , G. M. Madejski , M. N. Mazziotta , J. Mehault , P. F. Michelson , T. Mizuno , M. E. Monzani , A. Morselli , I. V. Moskalenko , S. Murgia , R. Nemmen , E. Nuss , M. Ohno , T. Ohsugi , D. Paneque , J. S. Perkins , M. Pesce-Rollins , F. Piron , G. Pivato , T. A. Porter , S. Rainò , R. Rando , M. Razzano , A. Reimer , O. Reimer , L. C. Reyes , S. Ritz , C. Romoli , M. Roth , P. M. Saz Parkinson , C. Sgrò , E. J. Siskind , G. Spandre , P. Spinelli , H. Takahashi , Y. Takeuchi , T. Tanaka , J. G. Thayer , J. B. Thayer , D. J. Thompson , L. Tibaldo , M. Tinivella , D. F. Torres , G. Tosti , E. Troja , V. Tronconi , T. L. Usher , J. Vandenbroucke , V. Vasileiou , G. Vianello , V. Vitale , A. P. Waite , M. Werner , B. L. Winer , K. S. Wood

The large majority of sources detected by the Fermi Gamma-ray Space Telescope are blazars, belonging in particular to the blazar subclass of BL Lacertae objects (BL Lacs). BL Lacs often have featureless optical spectra, which make it…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Hermine Landt

The Fermi observatory, with its Gamma-Ray Bursts monitor (GBM) and Large Area Telescope (LAT), is observing Gamma-ray Bursts with unprecedented spectral coverage and sensitivity, from ~10 keV to > 300 GeV. In the first 3 years of the…

High Energy Astrophysical Phenomena · Physics 2013-05-27 Giacomo Vianello

We report the Fermi Large Area Telescope (LAT) detection of two very-high-energy (VHE, E>100 GeV) gamma-ray photons from the directional vicinity of the distant (redshift, z = 1.1) blazar PKS 0426-380. The null hypothesis that both the 134…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Y. T. Tanaka , C. C. Cheung , Y. Inoue , L. Stawarz , M. Ajello , C. D. Dermer , D. L. Wood , A. Chekhtman , Y. Fukazawa , T. Mizuno , M. Ohno , D. Paneque , D. J. Thompson

The gamma-ray emission in broad-line blazars is generally explained as inverse Compton (IC) radiation of relativistic electrons in the jet scattering optical-UV photons from the Broad Line Region (BLR), the so-called BLR External Compton…

High Energy Astrophysical Phenomena · Physics 2018-05-16 L. Costamante , S. Cutini , G. Tosti , E. Antolini , A. Tramacere

The flat spectrum radio quasar 3C~454.3 underwent an extraordinary outburst in December 2009 when it became the brightest gamma-ray source in the sky for over one week. Its daily flux measured with the Fermi Large Area Telescope at photon…

High Energy Astrophysical Phenomena · Physics 2015-05-19 LAT collaboration
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