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PKS 2142-758 is a flat spectrum radio quasar which emits few, weak but significant gamma-ray flares in the MeV through GeV energy range. The first flare occured on April 4th, 2010, when the source reached a daily flux of (1.1 \pm 0.3) *…

We report on multiwavelength observations of the blazar PKS 0537-441 (z = 0.896) obtained from microwaves through gamma rays by SMA, REM, ATOM, Swift and Fermi during 2008 August-2010 April. Strong variability has been observed in gamma…

A study of blazar PKS 1424-418 was carried out using multi waveband data collected by Fermi-LAT, Swift-XRT, Swift-UVOT and SMARTS telescopes between MJD 56000 to MJD 56600 (14 Mar 2012 to 4 Nov 2013). Two flaring episodes were identified by…

High Energy Astrophysical Phenomena · Physics 2021-01-18 Jayant Abhir , Jophin Joseph , Sonal R Patel , Debanjan Bose

In this paper, we characterize the first $\gamma$-ray flaring episode of the FSRQ PKS 0346-27 (z=0.991), as revealed by Fermi-LAT monitoring data, and the concurrent multi-wavelength variability observed from radio through X-rays. The…

High Energy Astrophysical Phenomena · Physics 2019-07-17 R. Angioni , R. Nesci , J. D. Finke , S. Buson , S. Ciprini

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

PKS2142-75 (a.k.a. 2FGL J2147.4-7534) is a flat-spectrum radio quasar that was observed quasi-simultaneously by a suite of instruments across the elec- tromagnetic spectrum during two flaring states in April 2010 and August 2011 as well as…

Flat spectrum radio quasars (FSRQs) can suffer strong absorption above E = 25/(1+z) GeV, due to gamma-gamma interaction if the emitting region is at sub-parsec scale from the super-massive black hole (SMBH). Gamma-ray flares from these…

High Energy Astrophysical Phenomena · Physics 2018-08-22 G. Piano , P. Munar-Adrover , L. Pacciani , P. Romano , S. Vercellone , I. Donnarumma , F. Verrecchia , L. Carrasco , A. Porras , E. Recillas , M. Tavani

Since 2008 the Fermi/LAT instrument has delivered highly time-resolved gamma-ray spectra and detailed variability curves for a steadily increasing number of AGN. For detailed AGN studies the Fermi/LAT data have to be combined with, and…

High Energy Astrophysical Phenomena · Physics 2010-07-05 Lars Fuhrmann

Quasi-simultaneous observations of the Flat Spectrum Radio Quasar PKS 2326-502 were carried out in the gamma-ray, X-ray, UV, optical, near-infrared, and radio bands. Thanks to these observations we are able to characterize the spectral…

The Flat Spectrum Radio Quasar OP 313 is a high-redshift (z = 0.997) blazar that entered an intense gamma-ray active phase from November 2023 to March 2024, as observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space…

We have presented a multiwavelength temporal and spectral study of the Blazar PKS 0346-27 for the period 2019 January-2021 December (MJD 58484-59575) using data from Fermi-LAT (gamma-rays), Swift-XRT (X-rays) and Swift-UVOT (ultra-violet…

High Energy Astrophysical Phenomena · Physics 2023-01-25 Sushanth Reddy Kamaram , Raj Prince , Suman Pramanick , Debanjan Bose

PKS 1830$-$211 is a $\gamma$-ray emitting, high-redshift (z $= 2.507 \pm 0.002$), lensed flat-spectrum radio quasar. During the period mid-February to mid-April 2019, this source underwent a series of strong $\gamma$-ray flares that were…

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 detection of gamma-ray emission by Fermi-LAT from the radio loud Narrow Line Seyfert 1 PMN J0948+0022 (Abdo et al. 2009, ApJ 699, 976) triggered a multi-wavelength campaign between March and July 2009. Given its high compactness (Doi et…

We present multiwavelength observations and a model for flat spectrum radio quasar NVSS J141922-083830, originally classified as a blazar candidate of unknown type (BCU II object) in the Third Fermi-LAT AGN Catalog (3LAC). Relatively bright…

The \emph{Fermi} Large Area Telescope (LAT) discovered a new gamma-ray source near the Galactic plane, \object{Fermi J0109+6134}, when it flared brightly in 2010 February. The low Galactic latitude (b =-1.2\degr) indicated that the source…

We study the long-term behavior of the bright gamma-ray blazar PKS 0402-362. Over a span of approximately 12.5 years, from August 2008 to January 2021, we gathered Fermi-LAT temporal data and identified three distinct periods of intense…

High Energy Astrophysical Phenomena · Physics 2023-08-29 Avik kumar Das , Sandeep Kumar Mondal , Raj Prince

We investigate the radio and gamma-ray variability of the flat spectrum radio quasar PKS 1510-089 in the time range between 2010 November and 2012 January. In this period the source showed an intense activity, with two major gamma-ray…

The gamma-ray blazar PKS 0208-512 has shown strong periods of flaring, at all frequencies from radio to gamma-ray. This has led to its inclusion in the TANAMI project, which tracks the jets of southern AGN using VLBI as well as supporting…

High Energy Astrophysical Phenomena · Physics 2012-06-28 J. M. Blanchard , J. E. J. Lovell , J. Dickey , R. Ojha , M. Kadler , R. Nesci , P. G. Edwards , J. Stevens , M. Dutka , C. Muller , T. Pursimo

After a long low-activity period, a gamma-ray flare from the narrow-line Seyfert 1 PKS 1502+036 (z=0.4089) was detected by the Large Area Telescope (LAT) on board Fermi in 2015. On 2015 December 20 the source reached a daily peak flux, in…

High Energy Astrophysical Phenomena · Physics 2016-09-28 F. D'Ammando , M. Orienti , J. Finke , T. Hovatta , M. Giroletti , W. Max-Moerbeck , T. J. Pearson , A. C. S. Readhead , R. A. Reeves , J. L. Richards
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