Related papers: The WEBT Campaign on the Intermediate BL Lac Objec…

Multi-Epoch Multiwavelength Spectra and Models for Blazar 3C~279

Of the blazars detected by EGRET in GeV gamma rays, 3C 279 is not only the best-observed by EGRET, but also one of the best-monitored at lower frequencies. We have assembled eleven spectra, from GHz radio through GeV gamma rays, from the…

Astrophysics · Physics 2009-11-06 R. C. Hartman , M. Boettcher

On the redshift of TeV BL Lac objects

We report results of a spectroscopic campaign carried out at the 10 m Gran Telescopio Canarias for a sample of 22 BL Lac objects detected (or candidates) at TeV energies, aimed to determine or constrain their redshift. This is of…

Astrophysics of Galaxies · Physics 2017-03-22 Simona Paiano , Marco Landoni , Renato Falomo , Aldo Treves , Riccardo Scarpa , Chiara Righi

First detection of VHE gamma-ray emission from TXS~1515--273, study of its X-ray variability and spectral energy distribution

We report here on the first multi-wavelength (MWL) campaign on the blazar TXS 1515-273, undertaken in 2019 and extending from radio to very-high-energy gamma rays (VHE). Up until now, this blazar had not been the subject of any detailed MWL…

High Energy Astrophysical Phenomena · Physics 2021-07-21 MAGIC Collaboration , V. A. Acciari , S. Ansoldi , L. A. Antonelli , A. Arbet Engels , M. Artero , K. Asano , D. Baack , A. Babić , A. Baquero , U. Barres de Almeida , J. A. Barrio , I. Batković , J. Becerra González , W. Bednarek , L. Bellizzi , E. Bernardini , M. Bernardos , A. Berti , J. Besenrieder , W. Bhattacharyya , C. Bigongiari , A. Biland , O. Blanch , Ž. Bošnjak , G. Busetto , R. Carosi , G. Ceribella , M. Cerruti , Y. Chai , A. Chilingarian , S. Cikota , S. M. Colak , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , G. D'Amico , V. D'Elia , P. Da Vela , F. Dazzi , A. De Angelis1 , B. De Lotto , M. Delfino , J. Delgado , C. Delgado Mendez , D. Depaoli , F. Di Pierro , L. Di Venere , E. Do Souto Espiñeira , D. Dominis Prester , A. Donini , D. Dorner , M. Doro , D. Elsaesser , V. Fallah Ramazani , A. Fattorini , G. Ferrara , M. V. Fonseca , L. Font , C. Fruck , S. Fukami , R. J. García López , M. Garczarczyk , S. Gasparyan , M. Gaug , N. Giglietto , F. Giordano , P. Gliwny , N. Godinović , J. G. Green , D. Green , D. Hadasch , A. Hahn , L. Heckmann , J. Herrera , J. Hoang , D. Hrupec , M. Hütten , T. Inada , S. Inoue , K. Ishio , Y. Iwamura , I. Jiménez , J. Jormanainen , L. Jouvin , Y. Kajiwara , M. Karjalainen , D. Kerszberg , Y. Kobayashi , H. Kubo , J. Kushida , A. Lamastra , D. Lelas , F. Leone , E. Lindfors , S. Lombardi , F. Longo , R. López-Coto , M. López-Moya , A. López-Oramas , S. Loporchio , B. Machado de Oliveira Fraga , C. Maggio , P. Majumdar , M. Makariev , M. Mallamaci , G. Maneva , M. Manganaro , K. Mannheim , L. Maraschi , M. Mariotti , M. Martínez , D. Mazin , S. Menchiari , S. Mender , S. Mićanović , D. Miceli , T. Miener , M. Minev , J. M. Miranda , R. Mirzoyan , E. Molina , A. Moralejo , D. Morcuende , V. Moreno , E. Moretti , V. Neustroev , C. Nigro , K. Nilsson , K. Nishijima , K. Noda , S. Nozaki , Y. Ohtani , T. Oka , J. Otero-Santos , S. Paiano , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , L. Pavletić , P. Peñi , C. Perennes , M. Persic , P. G. Prada Moroni , E. Prandini , C. Priyadarshi , I. Puljak , W. Rhode , M. Ribó , J. Rico , C. Righi , A. Rugliancich , L. Saha , N. Sahakyan , T. Saito , S. Sakurai , K. Satalecka , F. G. Saturni , B. Schleicher , K. Schmidt , T. Schweizer , J. Sitarek , I. Šnidarić , D. Sobczynska , A. Spolon , A. Stamerra , D. Strom , M. Strzys , Y. Suda , T. Surić , M. Takahashi , F. Tavecchio , P. Temnikov , T. Terzić , M. Teshima , L. Tosti , S. Truzzi , A. Tutone , S. Ubach , J. van Scherpenberg , G. Vanzo , M. Vazquez Acosta , S. Ventura , V. Verguilov , C. F. Vigorito , V. Vitale , I. Vovk , M. Will , C. Wunderlich , D. Zaric , E. Bissaldi , G. Bonnoli , S. Cutini , F. D'Ammando , A. Nabizadeh , A. Marchini , M. Orienti

Fermi Gamma-ray Space Telescope Observations of the Gamma-ray Outburst from 3C 454.3 in November 2010

The flat-spectrum radio quasar 3C 454.3 underwent an extraordinary 5-day gamma-ray outburst in November 2010 where the daily flux measured with the Fermi Large Area Telescope (LAT) at photon energies E>100 MeV reached (66+/-2) x 10^-6 ph…

High Energy Astrophysical Phenomena · Physics 2017-02-22 LAT collaboration

Multiwavelength Monitoring of the BL Lacertae Object PKS 2155-304 in May 1994. I. The Ground-Based Campaign

Optical, near-infrared, and radio observations of the BL Lac object PKS2155-304 were obtained simultaneously with a continuous UV/EUV/X-ray monitoring campaign in 1994 May. Further optical observations were gathered throughout most of 1994.…

Astrophysics · Physics 2009-10-30 J. E. Pesce , C. M. Urry , L. Maraschi , A. Treves , P. Grandi , R. Kollgaard , E. Pian , P. Smith , H. Aller M. Aller , A. Barth , D. Buckley , E. Covino , A. Filippenko , E. Hooper , M. Joner L. Kedziora-Chudczer , D. Kilkenny , L. Knee , M. Kunkel , A. Layden , A. Magalhaes , F. Marang , V. Margoniner , C. Palma , A. Pereyra , C. Rodrigues , A. Schutte , M. Sitko , M. Tornikoski , J. van der Walt , F. van Wyk , P. Whitelock , S. Wolk

Identifying the 3FHL catalog: I. Results of the KOSMOS optical spectroscopy campaign

We present the results of the optical spectroscopy follow-up of a sample of 28 unclassified blazars from the Third Fermi-LAT Catalog of High-Energy Sources (3FHL). All the spectra were taken with the 4m Mayall telescope at Kitt Peak. With…

Astrophysics of Galaxies · Physics 2018-11-14 Stefano Marchesi , Amanpreet Kaur , Marco Ajello

Long-term optical polarization variability and multiwavelength analysis of Blazar Mrk 421

The results of 8-year R-band photopolarimetric data of blazar Mrk 421 collected from February 2008 to May 2016 are presented, along with extensive multiwavelength observations covering from radio to TeV $\gamma$-rays around the flares…

High Energy Astrophysical Phenomena · Physics 2017-09-06 Nissim Fraija , Erika Benítez , David Hiriart , Marco Sorcia , Jose Manuel López , Raul Mújica , Jose Ignacio Cabrera , Jose Antonio de Diego , Miriam Rojas-Luis , Felipe Salazar-Vázquez , Antonio Galván-Gámez

Radio to gamma-ray variability study of blazar S5 0716+714

We present the results of a series of radio, optical, X-ray and gamma-ray observations of the BL Lac object S50716+714 carried out between April 2007 and January 2011. The multi-frequency observations were obtained using several ground and…

High Energy Astrophysical Phenomena · Physics 2015-06-12 B. Rani , T. P. Krichbaum , L. Fuhrmann , M. Boettcher , B. Lott , H. D. Aller , M. F. Aller , E. Angelakis , U. Bach , D. Bastieri , A. D. Falcone , Y. Fukazawa , K. E. Gabanyi , A. C. Gupta , M. Gurwell , R. Itoh , K. S. Kawabata , M. Krips , A. A. Lähteenmäki , X. Liu , N. Marchili , W. Max-Moerbeck , I. Nestoras , E. Nieppola , G. Quintana-Lacaci , A. C. S. Readhead , J. L. Richards , M. Sasada , A. Sievers , K. Sokolovsky , M. Stroh , J. Tammi , M. Tornikoski , M. Uemura , H. Ungerechts , T. Urano , J. A. Zensus

Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009

We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi-instrument campaign spanning from 2009 March 15 to 2009 August 1 which includes, among other instruments, MAGIC, VERITAS, Whipple…

High Energy Astrophysical Phenomena · Physics 2017-07-05 M. L. Ahnen , S. Ansoldi , L. A. Antonelli , P. Antoranz , A. Babic , B. Banerjee , P. Bangale , U. Barres de Almeida , J. A. Barrio , J. Becerra González , W. Bednarek , E. Bernardini , A. Berti , B. Biasuzzi , A. Biland , O. Blanch , S. Bonnefoy , G. Bonnoli , F. Borracci , T. Bretz , S. Buson , A. Carosi , A. Chatterjee , R. Clavero , P. Colin , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , P. Da Vela , F. Dazzi , A. De Angelis , B. De Lotto , E. de Ona Wilhelmi , F. Di Pierro , M. Doert , A. Domínguez , D. Dominis Prester , D. Dorner , M. Doro , S. Einecke , D. Eisenacher Glawion , D. Elsaesser , M. Engelkemeier , V. Fallah Ramazani , A. Fernández-Barral , D. Fidalgo , M. V. Fonseca , L. Font , K. Frantzen , C. Fruck , D. Galindo , R. J. García López , M. Garczarczyk , D. Garrido Terrats , M. Gaug , P. Giammaria , N. Godinović , A. González Munoz , D. Gora , D. Guberman , D. Hadasch , A. Hahn , Y. Hanabata , M. Hayashida , J. Herrera , J. Hose , D. Hrupec , G. Hughes , W. Idec , K. Kodani , Y. Konno , H. Kubo , J. Kushida , A. La Barbera , D. Lelas , E. Lindfors , S. Lombardi , F. Longo , M. López , R. López-Coto , P. Majumdar , M. Makariev , K. Mallot , G. Maneva , M. Manganaro , K. Mannheim , L. Maraschi , B. Marcote , M. Mariotti , M. Martínez , D. Mazin , U. Menzel , J. M. Miranda , R. Mirzoyan , A. Moralejo , E. Moretti , D. Nakajima , V. Neustroev , A. Niedzwiecki , M. Nievas Rosillo , K. Nilsson , K. Nishijima , K. Noda , L. Nogués , A. Overkemping , S. Paiano , J. Palacio , M. Palatiello , D. Paneque , R. Paoletti , J. M. Paredes , X. Paredes-Fortuny , G. Pedaletti , M. Peresano , L. Perri , M. Persic , J. Poutanen , P. G. Prada Moroni , E. Prandini , I. Puljak , I. Reichardt , W. Rhode , M. Ribó , J. Rico , J. Rodriguez Garcia , T. Saito , K. Satalecka , S. Schröder , C. Schultz , T. Schweizer , S. N. Shore , A. Sillanpää , J. Sitarek , I. Snidaric , D. Sobczynska , A. Stamerra , T. Steinbring , M. Strzys , T. Surić , L. Takalo , F. Tavecchio , P. Temnikov , T. Terzić , D. Tescaro , M. Teshima , J. Thaele , D. F. Torres , T. Toyama , A. Treves , G. Vanzo , V. Verguilov , I. Vovk , J. E. Ward , M. Will , M. H. Wu , R. Zanin , A. U. Abeysekara , S. Archambault , A. Archer , W. Benbow , R. Bird , M. Buchovecky , J. H. Buckley , V. Bugaev , M. P. Connolly , W. Cui , H. J. Dickinson , A. Falcone , Q. Feng , J. P. Finley , H. Fleischhack , A. Flinders , L. Fortson , G. H. Gillanders , S. Griffin , J. Grube , M. Hütten , D. Hanna , J. Holder , T. B. Humensky , P. Kaaret , P. Kar , N. Kelley-Hoskins , M. Kertzman , D. Kieda , M. Krause , F. Krennrich , M. J. Lang , G. Maier , A. McCann , P. Moriarty , R. Mukherjee , D. Nieto , S. O'Brien , R. A. Ong , N. Otte , N. Park , J. Perkins , 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 , P. Wilcox , A. Wilhelm , D. A. Williams , B. Zitzer , S. Razzaque , M. Villata , C. M. Raiteri , H. D. Aller , M. F. Aller , V. M. Larionov , A. A. Arkharov , D. A. Blinov , N. V. Efimova , T. S. Grishina , V. A. Hagen-Thorn , E. N. Kopatskaya , L. V. Larionova , E. G. Larionova , D. A. Morozova , I. S. Troitsky , R. Ligustri , P. Calcidese , A. Berdyugin , O. M. Kurtanidze , M. G. Nikolashvili , G. N. Kimeridze , L. A. Sigua , S. O. Kurtanidze , R. A. Chigladze , W. P. Chen , E. Koptelova , T. Sakamoto , A. C. Sadun , J. W. Moody , C. Pace , R. Pearson , Y. Yatsu , Y. Mori , A. Carraminyana , L. Carrasco , E. de la Fuente , J. P. Norris , P. S. Smith , A. Wehrle , M. A. Gurwell , Alma Zook , C. Pagani , M. Perri , M. Capalbi , A. Cesarini , H. A. Krimm , Y. Y. Kovalev , Yu. A. Kovalev , E. Ros , A. B. Pushkarev , M. L. Lister , K. V. Sokolovsky , M. Kadler , G. Piner , A. Lähteenmäki , M. Tornikoski , E. Angelakis , T. P. Krichbaum , I. Nestoras , L Fuhrmann , J. A. Zensus , P. Cassaro , A. Orlati , G. Maccaferri , P. Leto , M. Giroletti , J. L. Richards , W. Max-Moerbeck , A. C. S. Readhead

3C 279 in Outburst in June 2015: A Broadband-SED Study Based on the INTEGRAL Detection

Blazars radiate from radio through gamma-ray frequencies thereby being ideal targets for multifrequency studies. Such studies allow constraining the properties of the emitting jet. 3C 279 is among the most notable blazars and therefore…

Astrophysics of Galaxies · Physics 2016-11-23 Eugenio Bottacini , Markus Boettcher , Elena Pian , Werner Collmar

A Time Resolved Study of the Broad Line Region in Blazar 3C 454.3

We present multi-epoch optical observations of the blazar 3C 454.3 (z = 0.859) from 2008 August through 2011 December, using the SMARTS Consortium 1.5m+RCSpectrograph and 1.3m+ANDICAM in Cerro Tololo, Chile. The spectra reveal that the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Jedidah C. Isler , C. Megan Urry , Paolo Coppi , Charles Bailyn , Ritaban Chatterjee , Giovanni Fossati , Erin W. Bonning , Laura Maraschi , Michelle Buxton

Spectroscopy of BL Lac objects of extraordinary luminosity

Aims. We aim to determine the redshift (or stringent lower limits) of a number of bright BL Lacs objects. Methods. We secured medium resolution optical and near-infrared spectra of 4 bright BL Lac objects of unknown redshift using the…

Astrophysics of Galaxies · Physics 2014-11-05 Marco Landoni , Renato Falomo , Aldo Treves , Boris Sbarufatti

Quasi-periodic behaviour in the optical and {\gamma}-ray light curves of blazars 3C 66A and B2 1633+38

We report on quasi-periodic variability found in two blazars included in the Steward Observatory Blazar Monitoring data sample: the BL Lac object 3C 66A and the Flat Spectrum Radio Quasar B2 1633+38. We collect optical photometric and…

High Energy Astrophysical Phenomena · Physics 2020-02-06 J. Otero-Santos , J. A. Acosta-Pulido , J. Becerra González , C. M. Raiteri , V. M. Larionov , P. Peñil , P. S. Smith , C. Ballester Niebla , G. A. Borman , M. I. Carnerero , N. Castro Segura , T. S. Grishina , E. N. Kopatskaya , E. G. Larionova , D. A. Morozova , A. A. Nikiforova , S. S. Savchenko , Yu. V. Troitskaya , I. S. Troitsky , A. A. Vasilyev , M. Villata

Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058-5234

We present the analysis of a total of 177h of high-quality optical time-series photometry of the helium atmosphere pulsating white dwarf (DBV) EC 20058-5234. The bulk of the observations (135h) were obtained during a WET campaign (XCOV15)…

Astrophysics · Physics 2008-06-17 WET Collaboration , D. J. Sullivan , T. S. Metcalfe , D. O'Donoghue , D. E. Winget , D. Kilkenny , F. van Wyk , A. Kanaan , S. O. Kepler , A. Nitta , S. D. Kawaler , M. H. Montgomery , R. E. Nather , M. S. O'Brien , A. Bischoff-Kim , M. Wood , X. J. Jiang , E. M. Leibowitz , P. Ibbetson , S. Zola , J. Krzesinski , G. Pajdosz , G. Vauclair , N. Dolez , M. Chevreton

Observation of the extremely bright flare of the FSRQ 3C279 with H.E.S.S. II

In June 2015, the Flat Spectrum Radio Quasar 3C 279 underwent an extremely bright gamma-ray flare, with an increase of the flux above 100 MeV by a factor 10 in less than 1 day, revealing an intrinsic variability timescale of 2 minutes as…

High Energy Astrophysical Phenomena · Physics 2019-08-14 C. Romoli , M. Zacharias , M. Meyer , F. Ait Benkhali , A. Jacholkowska , A. Wierzcholska , F. Jankowsky , J. P. Lenain

PKS 1502+106: a new and distant gamma-ray blazar in outburst discovered by the Fermi Large Area Telescope

The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope discovered a rapid (about 5 days duration), high-energy (E >100 MeV) gamma-ray outburst from a source identified with the blazar PKS 1502+106 (OR 103, S3 1502+10,…

High Energy Astrophysical Phenomena · Physics 2012-08-27 The Fermi LAT Collaboration , the Multifrequency Campaing Collaboration

Variability of the blazar 4C 38.41 (B3 1633+382) from GHz frequencies to GeV energies

The quasar-type blazar 4C 38.41 (B3 1633+382) experienced a large outburst in 2011, which was detected throughout the entire electromagnetic spectrum. We present the results of low-energy multifrequency monitoring by the GASP project of the…

High Energy Astrophysical Phenomena · Physics 2015-06-05 C. M. Raiteri , M. Villata , P. S. Smith , V. M. Larionov , J. A. Acosta-Pulido , M. F. Aller , F. D'Ammando , M. A. Gurwell , S. G. Jorstad , M. Joshi , O. M. Kurtanidze , A. Lähteenmäki , D. O. Mirzaqulov , I. Agudo , H. D. Aller , M. J. Arévalo , A. A. Arkharov , U. Bach , E. Benítez , A. Berdyugin , D. A. Blinov , K. Blumenthal , C. S. Buemi , A. Bueno , T. M. Carleton , M. I. Carnerero , D. Carosati , C. Casadio , W. P. Chen , A. Di Paola , M. Dolci , N. V. Efimova , Sh. A. Ehgamberdiev , J. L. Gómez , A. I. Gonzále , V. A. Hagen-Thorn , J. Heidt , D. Hiriart , Sh. Holikov , T. S. Konstantinova , E. N. Kopatskaya , E. Koptelova , S. O. Kurtanidze , E. G. Larionova , L. V. Larionova , J. León-Tavares , P. Leto , H. C. Lin , E. Lindfors , A. P. Marscher , I. M. McHardy , S. N. Molina , D. A. Morozova , R. Mujica , M. G. Nikolashvili , K. Nilsson , E. P. Ovcharov , N. Panwar , M. Pasanen , I. Puerto-Gimenez , R. Reinthal , G. M. Richter , J. A. Ros , T. Sakamoto , R. D. Schwartz , A. Sillanpää , N. Smith , L. O. Takalo , J. Tammi , B. Taylor , C. Thum , M. Tornikoski , C. Trigilio , I. S. Troitsky , G. Umana , A. T. Valcheva , A. E. Wehrle

Simultaneous multiwavelength observations of the blazar 1ES1959+650 at a low TeV flux

We present the results from a multiwavelength campaign on the TeV blazar 1ES 1959+650, performed in May, 2006. Data from the optical, UV, soft- and hard-X-ray and very high energy (VHE) gamma-ray (E > 100 GeV) bands were obtained with the…

Astrophysics · Physics 2009-06-23 G. Tagliaferri , L. Foschini , G. Ghisellini , L. Maraschi , G. Tosti , J. Albert , E. Aliu , H. Anderhub , P. Antoranz , C. Baixeras

Seven-Year Multi-Color Optical Monitoring of BL Lacertae Object S5 0716+714

We have monitored the BL Lac object S5 0716+714 in five intermediate optical wavebands from 2004 September to 2011 April. Here we present the data that include 8661 measurements which represents one of the largest databases obtained for an…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Yan Dai , Jianghua Wu , Zong-Hong Zhu , Xu Zhou , Jun Ma , Qirong Yuan , Lingzhi Wang

Multiple Components and Spectral Evolution of BL Lacertae as Revealed by Multiwavelength Variability and SED Modeling

BL Lac has entered an active state since 2020, with multiwavelength observations revealing intense flares. In this study, we conducted 12-night multicolor optical monitoring using an 85 cm telescope from 2020 September to 2024 June and…

High Energy Astrophysical Phenomena · Physics 2026-03-05 Hanxiao Xia , Ziming Wang , Jianghua Wu , Yue Fang , Shiyu Du