Related papers: Optical spectroscopy of Blazars for the Cherenkov …

A Three-Year Multi-Wavelength Study of the Very High Energy Gamma-ray Blazar 1ES 0229+200

The high-frequency-peaked BL Lacertae object 1ES 0229+200 is a relatively distant (z = 0.1396), hard-spectrum (Gamma ~ 2.5), very-high-energy-emitting (E > 100 GeV) gamma-ray blazar. Very-high-energy measurements of this active galactic…

High Energy Astrophysical Phenomena · Physics 2015-06-18 E. Aliu , S. Archambault , T. Arlen , T. Aune , B. Behera , M. Beilicke , W. Benbow , K. Berger , R. Bird , A. Bouvier , J. H. Buckley , V. Bugaev , K. Byrum , M. Cerruti , X. Chen , L. Ciupik , M. P. Connolly , W. Cui , C. Duke , J. Dumm , M. Errando , A. Falcone , S. Federici , Q. Feng , J. P. Finley , H. Fleischhack , P. Fortin , L. Fortson , A. Furniss , N. Galante , G. H. Gillanders , S. Griffin , S. T. Griffiths , J. Grube , G. Gyuk , D. Hanna , J. Holder , G. Hughes , T. B. Humensky , C. A. Johnson , P. Kaaret , M. Kertzman , Y. Khassen , D. Kieda , H. Krawczynski , F. Krennrich , M. J. Lang , A. S Madhavan , G. Maier , P. Majumdar , S. McArthur , A. McCann , K. Meagher , J. Millis , P. Moriarty , R. Mukherjee , D. Nieto , A. O'Faolain de Bhroithe , R. A. Ong , A. N. Otte , N. Park , J. S. Perkins , M. Pohl , A. Popkow , H. Prokoph , J. Quinn , K. Ragan , L. C. Reyes , P. T. Reynolds , G. T. Richards , E. Roache , G. H. Sembroski , A. W. Smith , D. Staszak , I. Telezhinsky , M. Theiling , A. Varlotta , V. V. Vassiliev , S. Vincent , S. P. Wakely , T. C. Weekes , A. Weinstein , R. Welsing , D. A. Williams , A. Zajczyk , B. Zitzer

Intra-night optical variability monitoring of $\gamma$-ray emitting blazars

We present the results obtained from our campaign to characterize the intra-night-optical variability properties of blazars detected by the {\it Fermi} Large Area Telescope. This involves R-band monitoring observations of a sample of 18…

High Energy Astrophysical Phenomena · Physics 2022-02-16 K. Subbu Ulaganatha Pandian , A. Natarajan , C. S. Stalin , Ashwani Pandey , S. Muneer , B. Natarajan

1WHSP: an IR-based sample of $\sim$1,000 VHE $\gamma$-ray blazar candidates

Blazars are the dominant type of extragalactic sources at microwave and at $\gamma$-ray energies. In the most energetic part of the electromagnetic spectrum (E>100GeV) a large fraction of high Galactic latitude sources are blazars of the…

High Energy Astrophysical Phenomena · Physics 2015-06-24 B. Arsioli , B. Fraga , P. Giommi , P. Padovani , P. M. Marrese

On the detectability of Lorentz invariance violation through anomalous multi-TeV $\gamma$-ray spectra of blazars

Cosmic opacity for very high-energy gamma rays ($E>10$ TeV) due to the interaction with the extragalactic background light can be strongly reduced because of possible Lorentz-violating terms in the particle dispersion relations expected,…

High Energy Astrophysical Phenomena · Physics 2015-12-16 F. Tavecchio , G. Bonnoli

New blazars from the cross-match of recent multi-frequency catalogs

Blazars are radio-loud active galactic nuclei well known for their non thermal emission spanning a wide range of frequencies. The Roma-BZCAT is, to date, the most comprehensive list of these sources. We performed the cross-match of several…

High Energy Astrophysical Phenomena · Physics 2015-05-04 A. Maselli , F. Massaro , R. D'Abrusco , G. Cusumano , V. La Parola , A. Segreto , G. Tosti

H.E.S.S. discovery of very-high-energy emission from the blazar PKS 0736+017: on the location of the $\gamma$-ray emitting region in FSRQs

With the installation of a new 28-m diameter imaging atmospheric Cherenkov telescope in the middle of the array, the H.E.S.S. instrument has entered since 2012 into its Phase II. The fifth large-size telescope is particularly important to…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Matteo Cerruti , Jean-Philippe Lenain , Heike Prokoph

Very-high-energy blazars: updates from VERITAS observations and multi-wavelength campaigns

VERITAS is an array of four 12-m atmospheric Cherenkov telescopes, designed to observe the very-high-energy (VHE; E $\geq$100 GeV) sky. Since 2007, it has detected more than 20 extra-galactic sources, the majority of which are…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Matteo Cerruti

Revisiting the TeV detection prospects for radio galaxies

Radio galaxies host relativistic jets oriented away from our line of sight, making them challenging targets for Very High Energy (VHE, E$>$100 GeV) $\gamma$-ray detectors. Indeed, out of $\sim100$ extragalactic sources detected at $E>100$…

High Energy Astrophysical Phenomena · Physics 2019-12-04 Roberto Angioni

Spectroscopically Confirmed Lyman-Alpha Emitters from Redshift 5 to 7 Behind Ten Galaxy Cluster Lenses

We present 36 spectroscopically confirmed intrinsically UV-faint Ly$\alpha$ emitting galaxies from follow-up observations with Keck/DEIMOS of gravitationally lensed high-redshift candidates. Candidates were selected to be between $5\lesssim…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Spencer Fuller , Brian Lemaux , Maruša Bradač , Austin Hoag , Kasper Schmidt , Kuang Huang , Victoria Strait , Charlotte Mason , Tommaso Treu , Laura Pentericci , Michele Trenti , Alaina Henry , Matt Malkan

Very high energy $\gamma$-ray emission from two blazars of unknown redshift and upper limits on their distance

We report on the detection of very-high-energy (VHE; $E > 100$ GeV) $\gamma$-ray emission from the BL Lac objects KUV 00311-1938 and PKS 1440-389 with the High Energy Stereoscopic System (H.E.S.S.). H.E.S.S. observations were accompanied or…

High Energy Astrophysical Phenomena · Physics 2020-04-29 H. E. S. S. Collaboration , H. Abdalla , R. Adam , F. Aharonian , F. Ait Benkhali , E. O. Angüner , M. Arakawa , C. Arcaro , C. Armand , T. Armstrong , H. Ashkar , M. Backes , V. Baghmanyan , V. Barbosa Martins , A. Barnacka , M. Barnard , Y. Becherini , D. Berge , K. Bernlöhr , M. Böttcher , C. Boisson , J. Bolmont , S. Bonnefoy , J. Bregeon , M. Breuhaus , F. Brun , P. Brun , M. Bryan , M. Büchele , T. Bulik , T. Bylund , S. Caroff , A. Carosi , S. Casanova , T. Chand , S. Chandra , A. Chen , G. Cotter , M. Curyło , I. D. Davids , J. Davies , C. Deil , J. Devin , P. deWilt , L. Dirson , A. Djannati-Ataï , A. Dmytriiev , A. Donath , V. Doroshenko , J. Dyks , K. Egberts , F. Eichhorn , G. Emery , J. -P. Ernenwein , K. Feijen , S. Fegan , A. Fiasson , G. Fontaine , S. Funk , M. Füßling , S. Gabici , Y. A. Gallant , G. Giavitto , L. Giunti , D. Glawion , J. F. Glicenstein , D. Gottschall , M. -H. Grondin , J. Hahn , M. Haupt , G. Hermann , J. A. Hinton , W. Hofmann , C. Hoischen , T. L. Holch , M. Holler , M. H{\"}orbe , D. Horns , D. Huber , H. Iwasaki , M. Jamrozy , D. Jankowsky , F. Jankowsky , A. Jardin-Blicq , V. Joshi , I. Jung-Richardt , M. A. Kastendieck , K. Katarzynski , M. Katsuragawa , U. Katz , D. Khangulyan , B. Khélifi , S. Klepser , W. Kluzniak , Nu. Komin , R. Konno , K. Kosack , D. Kostunin , M. Kreter , G. Lamanna , A. Lemière , M. Lemoine-Goumard , J. -P. Lenain , E. Leser , C. Levy , T. Lohse , I. Lypova , J. Mackey , J. Majumdar , D. Malyshev , D. Malyshev , V. Marandon , P. Marchegiani , A. Marcowith , A. Mares , G. Martí-Devesa , R. Marx , G. Maurin , P. J. Meintjes , R. Moderski , M. Mohamed , L. Mohrmann , C. Moore , P. Morris , E. Moulin , J. Muller , T. Murach , S. Nakashima , K. Nakashima , M. de Naurois , H. Ndiyavala , F. Niederwanger , J. Niemiec , L. Oakes , P. O'Brien , H. Odaka , S. Ohm , E. de Ona Wilhelmi , M. Ostrowski , M. Panter , R. D. Parsons , B. Peyaud , Q. Piel , S. Pita , V. Poireau , A. Priyana Noel , D. A. Prokhorov , H. Prokoph , G. Pühlhofer , M. Punch , A. Quirrenbach , S. Raab , R. Rauth , A. Reimer , O. Reimer , Q. Remy , M. Renaud , F. Rieger , L. Rinchiuso , C. Romoli , G. Rowell , B. Rudak , E. Ruiz-Velasco , V. Sahakian , S. Sailer , S. Saito , D. A. Sanchez , A. Santangelo , M. Sasaki , M. Scalici , F. Schüssler , H. M. Schutte , U. Schwanke , S. Schwemmer , M. Seglar-Arroyo , M. Senniappan , A. S. Seyffert , N. Shafi , K. Shiningayamwe , R. Simoni , A. Sinha , H. Sol , A. Specovius , S. Spencer , M. Spir-Jacob , Ł. Stawarz , R. Steenkamp , C. Stegmann , C. Steppa , T. Takahashi , T. Tavernier , A. M. Taylor , R. Terrier , D. Tiziani , M. Tluczykont , L. Tomankova , C. Trichard , M. Tsirou , N. Tsuji , R. Tuffs , Y. Uchiyama , D. J. van der Walt , C. van Eldik , C. van Rensburg , B. van Soelen , G. Vasileiadis , J. Veh , C. Venter , P. Vincent , J. Vink , H. J. Völk , T. Vuillaume , Z. Wadiasingh , S. J. Wagner , J. Watson , F. Werner , R. White , A. Wierzcholska , R. Yang , H. Yoneda , M. Zacharias , R. Zanin , D. Zargaryan , A. A. Zdziarski , A. Zech , S. J. Zhu , J. Zorn , N. Żywucka , M. Cerruti

Search for muon-neutrino emission from GeV and TeV gamma-ray flaring blazars using five years of data of the ANTARES telescope

The ANTARES telescope is well-suited for detecting astrophysical transient neutrino sources as it can observe a full hemisphere of the sky at all times with a high duty cycle. The background due to atmospheric particles can be drastically…

High Energy Astrophysical Phenomena · Physics 2016-08-08 S. Adrián-Martínez , A. Albert , M. André , G. Anton , M. Ardid , J. -J. Aubert , B. Baret , J. Barrios-Martí , S. Basa , V. Bertin , S. Biagi , C. Bogazzi , R. Bormuth , M. Bou-Cabo , M. C. Bouwhuis , R. Bruijn , J. Brunner , J. Busto , A. Capone , L. Caramete , J. Carr , T. Chiarusi , M. Circella , R. Coniglione , H. Costantini , P. Coyle , A. Creusot , I. Dekeyser , A. Deschamps , G. De Bonis , C. Distefano , C. Donzaud , D. Dornic , D. Drouhin , A. Dumas , T. Eberl , D. Elsässer , A. Enzenhöfer , K. Fehn , I. Felis , P. Fermani , F. Folger , L. A. Fusco , S. Galatà , P. Gay , S. Geißelsöder , K. Geyer , V. Giordano , A. Gleixner , R. Gracia-Ruiz , K. Graf , H. van Haren , A. J. Heijboer , Y. Hello , J. J. Hernández-Rey , A. Herrero , J. Hößl , J. Hofestädt , C. Hugon , C. W James , M. de Jong , M. Kadler , O. Kalekin , U. Katz , D. Kießling , P. Kooijman , A. Kouchner , I. Kreykenbohm , V. Kulikovskiy , R. Lahmann , G. Lambard , D. Lattuada , D. Lefèvre , E. Leonora , S. Loucatos , S. Mangano , A. Margiotta , J. A. Martínez-Mora , S. Martini , A. Mathieu , T. Michael , P. Migliozzi , A. Moussa , C. Mueller , M. Neff , E. Nezri , G. E. Păvălaş , C. Pellegrino , C. Perrina , P. Piattelli , V. Popa , T. Pradier , C. Racca , G. Riccobene , R. Richter , K. Roensch , A. Rostovtsev , M. Saldaña , D. F. E. Samtleben , M. Sanguineti , P. Sapienza , J. Schmid , J. Schnabel , S. Schulte , F. Schüssler , T. Seitz , C. Sieger , M. Spurio , J. J. M. Steijger , Th. Stolarczyk , A. Sánchez-Losa , M. Taiuti , C. Tamburini , A. Trovato , M. Tselengidou , C. Tönnis , D. Turpin , B. Vallage , C. Vallée , V. Van Elewyck , E. Visser , D. Vivolo , S. Wagner , J. Wilms , J. D. Zornoza , J. Zúñiga

Prospects for Detecting Gamma-Ray Bursts at Very High Energies with the Cherenkov Telescope Array

We discuss the prospects for the detection of gamma-ray bursts (GRBs) by the Cherenkov Telescope Array (CTA), the next generation, ground-based facility of imaging atmospheric Cherenkov telescopes (IACTs) operating above a few tens of GeV.…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Jun Kakuwa , Kohta Murase , Kenji Toma , Susumu Inoue , Ryo Yamazaki , Kunihito Ioka

Detecting and characterizing pulsar halos with the Cherenkov Telescope Array Observatory

The recently identified source class of pulsar halos may be populated and bright enough at TeV energies to constitute a large fraction of the sources that will be observed with the Cherenkov Telescope Array (CTA), especially in the context…

High Energy Astrophysical Phenomena · Physics 2023-10-03 Christopher Eckner

Optical spectroscopic observations of gamma-ray blazar candidates VIII: the 2016-2017 follow up campaign carried out at SPM, NOT, KPNO and SOAR telescopes

The third Fermi source catalog lists 3033 gamma-ray sources above $4\sigma$ significance. More than 30% are classified as either unidentified/unassociated Gamma-ray sources (UGSs), with about 20% classified as Blazar candidates of uncertain…

Astrophysics of Galaxies · Physics 2019-03-26 Marchesini , E. J. , Peña-Herazo , H. A. , Álvarez Crespo , N. , Ricci , F. , M. Negro , Milisavljevic , D. , Massaro , F. , Masetti , N. , Landoni , M. , Chavushyan , V. , D'Abrusco , R. , Jiménez-Bailón , E. , La Franca , F. , Paggi , A. , Smith , H. A. , Tosti , G.

Models for the Spectral Energy Distributions and Variability of Blazars

In this review, recent progress in theoretical models for blazar emission will be summarized. The salient features of both leptonic and lepto-hadronic approaches to modeling blazar spectral energy distributions will be reviewed. I will…

High Energy Astrophysical Phenomena · Physics 2010-06-28 Markus Boettcher

Imaging Redshift Estimates for BL Lacertae Objects

We have obtained high dynamic range, good natural seeing i' images of BL Lacertae objects (BL Lacs) to search for the AGN host and thus constrain the source redshift. These objects are drawn from a sample of bright flat-spectrum radio…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Aaron M. Meisner , Roger W. Romani

Gamma-ray blazar spectra with H.E.S.S. II mono analysis: the case of PKS 2155-304 and PG 1553+113

The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to…

High Energy Astrophysical Phenomena · Physics 2017-04-12 H. E. S. S. Collaboration , : , H. Abdalla , A. Abramowski , F. Aharonian , F. Ait Benkhali , A. G. Akhperjanian , T. Andersson , E. O. Angüner , M. Arrieta , P. Aubert , M. Backes , A. Balzer , M. Barnard , Y. Becherini , J. Becker Tjus , D. Berge , S. Bernhard , K. Bernlöhr , R. Blackwell , M. Böttcher , C. Boisson , J. Bolmont , P. Bordas , F. Brun , P. Brun , M. Bryan , T. Bulik , M. Capasso , J. Carr , S. Casanova , M. Cerruti , N. Chakraborty , R. Chalme-Calvet , R. C. G. Chaves , A. Chen , J. Chevalier , M. Chrétien , S. Colafrancesco , G. Cologna , B. Condon , J. Conrad , C. Couturier , Y. Cui , I. D. Davids , B. Degrange , C. Deil , J. Devin , P. deWilt , L. Dirson , A. Djannati-Ataï , W. Domainko , A. Donath , L. O'C. Drury , G. Dubus , K. Dutson , J. Dyks , T. Edwards , K. Egberts , P. Eger , J. -P. Ernenwein , S. Eschbach , C. Farnier , S. Fegan , M. V. Fern , A. Fiasson , G. Fontaine , A. Förster , S. Funk , M. Füßling , S. Gabici , M. Gajdus , Y. A. Gallant , T. Garrigoux , G. Giavitto , B. Giebels , J. F. Glicenstein , D. Gottschall , A. Goyal , M. -H. Grondin , D. Hadasch , J. Hahn , M. Haupt , J. Hawkes , G. Heinzelmann , G. Henri , G. Hermann , O. Hervet , A. Hillert , J. A. Hinton , W. Hofmann , C. Hoischen , M. Holler , D. Horns , A. Ivascenko , A. Jacholkowska , M. Jamrozy , M. Janiak , D. Jankowsky , F. Jankowsky , M. Jingo , T. Jogler , L. Jouvin , I. Jung-Richardt , M. A. Kastendieck , K. Katarzyński , U. Katz , D. Kerszberg , B. Khélifi , M. Kieffer , J. King , S. Klepser , D. Klochkov , W. Kluźniak , D. Kolitzus , Nu. Komin , K. Kosack , S. Krakau , M. Kraus , F. Krayzel , P. P. Krüger , H. Laffon , G. Lamanna , J. Lau , J. -P. Lees , J. Lefaucheur , V. Lefranc , A. Lemière , M. Lemoine-Goumard , J. -P. Lenain , E. Leser , T. Lohse , M. Lorentz , R. Liu , R. López-Coto , I. Lypova , V. Mar , A. Marcowith , C. Mariaud , R. Marx , G. Maurin , N. Maxted , M. Mayer , P. J. Meintjes , M. Meyer , A. M. W. Mitchell , R. Moderski , M. Mohamed , L. Mohrmann , K. Morå , E. Moulin , T. Murach , M. de Naurois , F. Niederwanger , J. Niemiec , L. Oakes , P. O'Brien , H. Odaka , S. Öttl , S. Ohm , M. Ostrowski , I. Oya , M. Padovani , M. Panter , R. D. Parsons , M. Paz Arribas , N. W. Pekeur , G. Pelletier , C. Perennes , P. -O. Petrucci , B. Peyaud , S. Pita , H. Poon , D. Prokhorov , H. Prokoph , G. Pühlhofer , M. Punch , A. Quirrenbach , S. Raab , A. Reimer , O. Reimer , M. Renaud , R. de los Reyes , F. Rieger , C. Romoli , S. Rosier-Lees , G. Rowell , B. Rudak , C. B. Rulten , V. Sahakian , D. Salek , D. A. Sanchez , A. Santangelo , M. Sasaki , R. Schlickeiser , F. Schüssler , A. Schulz , U. Schwanke , S. Schwemmer , M. Settimo , A. S. Seyffert , N. Shafi , I. Shilon , R. Simoni , H. Sol , F. Spanier , G. Spengler , F. Spies , Ł. Stawarz , R. Steenkamp , C. Stegmann , F. Stinzing , K. Stycz , I. Sushch , J. -P. Tavernet , T. Tavernier , A. M. Taylor , R. Terrier , L. Tibaldo , D. Tiziani , M. Tluczykont , C. Trichard , R. Tuffs , Y. Uchiyama , D. J. van der Walt , C. van Eldik , B. van Soelen , G. Vasileiadis , J. Veh , C. Venter , A. Viana , P. Vincent , J. Vink , F. Voisin , H. J. Völk , T. Vuillaume , Z. Wadiasingh , S. J. Wagner , P. Wagner , R. M. Wagner , R. White , A. Wierzcholska , P. Willmann , A. Wörnlein , D. Wouters , R. Yang , V. Zabalza , D. Zaborov , M. Zacharias , A. A. Zdziarski , A. Zech , F. Zefi , A. Ziegler , N. Żywucka , LAT Collaboration , : , M. Ackermann , M. Ajello , L. Baldini , G. Barbiellini , R. Bellazzini , R. D. Bl , R. Bonino , J. Bregeon , P. Bruel , R. Buehler , G. A. Cali , R. A. Cameron , M. Caragiulo , P. A. Caraveo , E. Cavazzuti , C. Cecchi , J. Chiang , G. Chiaro , S. Ciprini , J. Cohen-Tanugi , F. Costanza , S. Cutini , F. D'Amm , F. de Palma , R. Desiante , N. Di Lalla , M. Di Mauro , L. Di Venere , B. Donaggio , C. Favuzzi , W. B. Focke , P. Fusco , F. Gargano , D. Gasparrini , N. Giglietto , F. Giordano , M. Giroletti , L. Guillemot , S. Guiriec , D. Horan , G. Jóhannesson , T. Kamae , S. Kensei , D. Kocevski , S. Larsson , J. Li , F. Longo , F. Loparco , M. N. Lovellette , P. Lubrano , S. Maldera , A. Manfreda , M. N. Mazziotta , P. F. Michelson , T. Mizuno , M. E. Monzani , A. Morselli , M. Negro , E. Nuss , M. Orienti , E. Orl , D. Paneque , J. S. Perkins , M. Pesce-Rollins , F. Piron , G. Pivato , T. A. Porter , G. Principe , S. Rainò , M. Razzano , D. Simone , E. J. Siskind , F. Spada , P. Spinelli , J. B. Thayer , D. F. Torres , E. Torresi , E. Troja , G. Vianello , K. S. Wood

Optical spectroscopy of BL Lacertae objects. Broad lines, companion galaxies and redshift lower limits

Aims: We present optical spectroscopy of a sample of BL Lac objects, to determine their redshift, to study their broad emission line properties and to characterize their close environment. Methods: Twelve objects were observed using the ESO…

Astrophysics · Physics 2009-11-11 B. Sbarufatti , R. Falomo , A. Treves , J. Kotilainen , .

Optical Spectra of Flat-Spectrum ICRF Radio Sources

Continuing our program of spectroscopic observations of ICRF sources, we present redshifts for 120 quasars and radio galaxies. Data were obtained with five telescopes: the 3.58m ESO New Technology Telescope (NTT), the two 8.2m Gemini…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-15 Oleg Titov , Laura M. Stanford , Helen M. Johnston , Tapio Pursimo , Richard W. Hunstead , David L. Jauncey , K. Maslennikov , A. Boldycheva

Gamma-ray Blazars Within the First 2 Billion Years

The detection of high-redshift ($z>$3) blazars enables the study of the evolution of the most luminous relativistic jets over cosmic time. More importantly, high-redshift blazars tend to host massive black holes and can be used to constrain…

High Energy Astrophysical Phenomena · Physics 2017-04-25 Large Area Telescope Collaboration