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We report Fermi/LAT observations and broad-band spectral modeling of the radio-loud active galaxy 4C +55.17 (z=0.896), formally classified as a flat-spectrum radio quasar. Using 19 months of all-sky survey Fermi/LAT data, we detect a…

The radio galaxy PKS 1007+142 is classified as a compact steep-spectrum source (CSS) and belongs to the class of young Active Galactic Nuclei (AGNs). In this paper, we investigate the $\gamma$-ray emission from this CSS by conducting a…

High Energy Astrophysical Phenomena · Physics 2024-04-26 Tan-Zheng Wu , Yu-Wei Yu , Ying-Ying Gan , Hai-Ming Zhang , Jin Zhang

In May - July 2014, the flat spectrum radio quasar 3C 454.3 exhibited strong flaring behaviour. Observations with the Large Area Telescope detector on-board the Fermi Gamma-ray Space Telescope captured the $\gamma$-ray flux at energies 0.1…

High Energy Astrophysical Phenomena · Physics 2016-03-23 Rosemary T. Coogan , Anthony M. Brown , Paula M. Chadwick

Determining the location of $\gamma$-ray emission in blazar jets is a challenging task. Pinpointing the exact location of $\gamma$-ray production within a relativistic jet can place strong constraints on our understanding of high-energy…

High Energy Astrophysical Phenomena · Physics 2021-12-20 F. Rösch , M. Kadler , E. Ros , M. Gurwell , T. Hovatta , M. Kreter , N. R. MacDonald , A. C. S. Readhead

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…

Extended gamma-ray sources provide significant information about particle propagation. 4FGL J1626.0-4917 was labeled as an unassociated source in 4FGL catalog without known counterparts at other wavelengths. We report an analysis on 4FGL…

High Energy Astrophysical Phenomena · Physics 2026-05-01 Ziwei Ou , Jie Wang

The Large Area Telescope on board the Fermi Gamma-ray Space Telescope detected a strong gamma-ray flare on 2011 May 15 from a source identified as 4C 49.22, a flat spectrum radio quasar also known as S4 1150+49. This blazar, characterised…

The active galactic nucleus 4C +28.07 is a flat spectrum radio quasar, one of the brightest at $\gamma$-ray energies. We study its multi-wavelength emission by analysing $\sim12.3$ years of \textit{Fermi-LAT} data in the $\gamma$-ray band…

High Energy Astrophysical Phenomena · Physics 2022-01-10 Davit Zargaryan , Jonathan Mackey , Thibault Barnouin , Felix Aharonian

We report the first detection of GeV gamma-ray flaring activity from the compact symmetric object (CSO)-like source 4C 76.03, based on 17 years of Fermi-LAT observations. Its long-term, time-averaged gamma-ray properties are consistent with…

High Energy Astrophysical Phenomena · Physics 2026-03-24 Xiong Jiang , Hai Lei , Hao-Yi Huang , Wei Zhang , Yang-Ji Li , Da-Ming Wei

We report the analysis of Fermi Large Area Telescope data from five years of observations of the broad line radio galaxy 3C 120. The accumulation of larger data set results in the detection of high-energy $\gamma$-rays up to 10 GeV, with a…

High Energy Astrophysical Phenomena · Physics 2015-02-04 N. Sahakyan , D. Zargaryan , V. Baghmanyan

The Fermi Large Area Telescope revealed that the extragalactic gamma-ray sky is dominated by blazars, active galactic nuclei (AGN) whose jet is seen at very small angle to the line of sight. To associate and then classify the gamma-ray…

Astrophysics of Galaxies · Physics 2018-05-09 K. É. Gabányi , S. Frey , T. An

We report the discovery by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope of high-energy gamma-ray (GeV) emission from the flat-spectrum radio quasar PKS 1454-354 (z=1.424). On 4 September 2008 the source rose to…

High Energy Astrophysical Phenomena · Physics 2012-08-27 LAT Collaboration , A. A. Abdo , P. G. Edwards , M. M. Chester , D. N. Burrows , M. Hauser , S. Wagner

4C +21.35 is a flat-spectrum-radio-quasar-type blazar, in which the rapid variability of very high energy (VHE, $E_{\gamma}\gtrsim 100$\,GeV) emission as short as $\sim$ 10 minutes was observed by MAGIC Cherenkov telescopes, and the VHE…

High Energy Astrophysical Phenomena · Physics 2015-07-15 Maichang Lei , Jiancheng Wang

SS 433 is a microquasar whose relativistic jets precess every ~162 days, providing a laboratory for jet-interstellar medium interactions. We present a comprehensive analysis of 16 years of Fermi Large Area Telescope data (August…

High Energy Astrophysical Phenomena · Physics 2026-05-18 Ömer Faruk Çoban , Diego F. Torres , Jian Li , Daniela Hadasch , Agnibha De Sarkar , Matthew Kerr

We report the discovery of an extended GeV {\gamma}-ray source, 4FGL J0330.7+5845e, associated with the star-forming region AFGL 490 using 17 years of Fermi-LAT data. The emission is spatially coincident with a dense molecular cloud and…

High Energy Astrophysical Phenomena · Physics 2026-05-18 Li-Nuo Yang , Sheng Tang , Pak-Hin Thomas Tam

The bright gamma-ray quasar 4C +55.17 is a distant source ($z = 0.896$) with a hard spectrum at GeV energies as observed by the Large Area Telescope (LAT) on board the {{\it Fermi}} satellite. This source is identified as a good source…

High Energy Astrophysical Phenomena · Physics 2015-06-18 MAGIC Collaboration , J. Aleksić , S. Ansoldi , L. A. Antonelli , P. Antoranz , A. Babic , P. Bangale , U. Barres de Almeida , J. A. Barrio , J. Becerra González , W. Bednarek , K. Berger , E. Bernardini , A. Biland , O. Blanch , R. K. Bock , S. Bonnefoy , G. Bonnoli , F. Borracci , T. Bretz , E. Carmona , A. Carosi , D. Carreto Fidalgo , P. Colin , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , P. Da Vela , F. Dazzi , A. De Angelis , G. De Caneva , B. De Lotto , C. Delgado Mendez , M. Doert , A. Domínguez , D. Dominis Prester , D. Dorner , M. Doro , S. Einecke , D. Eisenacher , D. Elsaesser , E. Farina , D. Ferenc , M. V. Fonseca , L. Font , K. Frantzen , C. Fruck , R. J. García López , M. Garczarczyk , D. Garrido Terrats , M. Gaug , G. Giavitto , N. Godinović , A. González Mu\ noz , S. R. Gozzini , D. Hadasch , M. Hayashida , A. Herrero , D. Hildebrand , J. Hose , D. Hrupec , W. Idec , V. Kadenius , H. Kellermann , M. L. Knoetig , K. Kodani , Y. Konno , J. Krause , H. Kubo , J. Kushida , A. La Barbera , D. Lelas , N. Lewandowska , E. Lindfors , S. Lombardi , M. López , R. López-Coto , A. López-Oramas , E. Lorenz , I. Lozano , M. Makariev , K. Mallot , G. Maneva , N. Mankuzhiyil , K. Mannheim , L. Maraschi , B. Marcote , M. Mariotti , M. Martínez , D. Mazin , U. Menzel , M. Meucci , J. M. Miranda , R. Mirzoyan , A. Moralejo , P. Munar-Adrover , D. Nakajima , A. Niedzwiecki , K. Nilsson , K. Nishijima , N. Nowak , R. Orito , A. Overkemping , S. Paiano , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , X. Paredes-Fortuny , S. Partini , M. Persic , F. Prada , P. G. Prada Moroni , E. Prandini , S. Preziuso , I. Puljak , R. Reinthal , W. Rhode , M. Ribó , J. Rico , J. Rodriguez Garcia , S. Rügamer , A. Saggion , T. Saito , K. Saito , M. Salvati , K. Satalecka , V. Scalzotto , V. Scapin , C. Schultz , T. Schweizer , S. N. Shore , A. Sillanpää , J. Sitarek , I. Snidaric , D. Sobczynska , F. Spanier , V. Stamatescu , A. Stamerra , T. Steinbring , J. Storz , S. Sun , T. Surić , L. Takalo , H. Takami , F. Tavecchio , P. Temnikov , T. Terzić , D. Tescaro , M. Teshima , J. Thaele , O. Tibolla , D. F. Torres , T. Toyama , A. Treves , P. Vogler , R. M. Wagner , F. Zandanel , R. Zanin

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

We first report GeV $\gamma$-ray emission from supernova remnant (SNR) G15.9+0.2 in this work. The results show that its power-law spectral index is 2.94$\pm$0.25 with a 6.47$\sigma$ significance level, and the $\gamma$-ray emission can be…

High Energy Astrophysical Phenomena · Physics 2021-10-27 Yunchuan Xiang , Zejun Jiang , Mengyao Tang

3C 216 is an extragalactic radio source classified as a compact steep spectrum (CSS) object, associated with the source 4FGL J0910.0+4257 detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. The source…

High Energy Astrophysical Phenomena · Physics 2025-06-11 Federica Giacchino , Giovanni La Mura , Stefano Ciprini , Dario Gasparrini , Marcello Giroletti , Marco Laurenti

We analyze the emission in the 0.3-30 GeV energy range of Gamma-Ray Bursts detected with the Fermi Gamma-ray Space Telescope. We concentrate on bursts that were previously only detected with the Gamma-Ray Burst Monitor in the keV energy…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Johannes Lange , Martin Pohl
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