Abdalla H, Abramowski A, Aharonian F, Benkhali FA, Akhperjanian AG, Andersson T, Anguener EO, Arrieta M, Aubert P, Backes M, Balzer A, Barnard M, Becherini Y, Tjus JB, Berge D, Bernhard S, Bernloehr K, Blackwell R, Bottcher M, Boisson C, Bolmont J, Bordas P, Brun F, Brun P, Bryan M, Bulik T, Capasso M, Carr J, Casanova S, Cerruti M, Chakraborty N, Chalme-Calvet R, Chaves RCG, Chen A, Chevalier J, Chretien M, Colafrancesco S, Cologna G, Condon B, Conrad J, Couturier C, Cui Y, Davids ID, Degrange B, Deil C, Devin J, Dewilt P, Dirson L, Djannati-Atai A, Domainko W, Donath A, Drury LO, Dubus G, Dutson K, Dyks J, Edwards T, Egberts K, Eger P, Ernenwein JP, Eschbach S, Farnier C, Fegan S, Fernandes MV, Fiasson A, Fontaine G, Forster A, Funk S, Fuessling M, Gabici S, Gajdus M, Gallant YA, Garrigoux T, Giavitto G, Giebels B, Glicenstein JF, Gottschall D, Goyal A, Grondin MH, Hadasch D, Hahn J, Haupt M, Hawkes J, Heinzelmann G, Henri G, Hermann G, Hervet O, Hillert A, Hinton JA, Hofmann W, Hoischen C, Holler M, Horns D, Ivascenko A, Jacholkowska A, Jamrozy M, Janiak M, Jankowsky D, Jankowsky F, Jingo M, Jogler T, Jouvin L, Jung-Richardt I, Kastendieck MA, Katarzynski K, Katz U, Kerszberg D, Khelifi B, Kieffer M, King J, Klepser S, Klochkov D, Kluzniak W, Kolitzus D, Komin N, Kosack K, Krakau S, Kraus M, Krayzel F, Kruger PP, Laffon H, Lamanna G, Lau J, Lees JP, Lefaucheur J, Lefranc V, Lemiere A, Lemoine-Goumard M, Lenain JP, Leser E, Lohse T, Lorentz M, Liu R, Lopez-Coto R, Lypova I, Marandon V, Marcowith A, Mariaud C, Marx R, Maurin G, Maxted N, Mayer M, Meintjes PJ, Meyer M, Mitchell AMW, Moderski R, Mohamed M, Mohrmann L, Mora K, Moulin E, Murach T, De Naurois M, Niederwanger F, Niemiec J, Oakes L, O'Brien P, Odaka H, Oul S, Ohm S, Ostrowski M, Oya I, Padovani M, Panter M, Parsons RD, Arribas MP, Pekeur NW, Pelletier G, Perennes C, Petrucci PO, Peyaud B, Pita S, Poon H, Prokhorov D, Prokoph H, Puehlhofer G, Punch M, Quirrenbach A, Raab S, Reimer A, Reimer O, Renaud M, De Los Reyes R, Rieger F, Romoli C, Rosier-Lees S, Rowell G, Rudak B, Rulten CB, Sahakian V, Salek D, Sanchez DA, Santangelo A, Sasaki M, Schlickeiser R, Schussler F, Schulz A, Schwanke U, Schwemmer S, Settimo M, Seyffert AS, Shafi N, Shilon I, Simoni R, Sol H, Spanier F, Spengler G, Spies F, Stawarz L, Steenkamp R, Stegmann C, Stinzing F, Stycz K, Sushch I, Tavernet JP, Tavernier T, Taylor AM, Terrier R, Tibaldo L, Tiziani D, Tluczykont M, Trichard C, Tuffs R, Uchiyama Y, Van Der Walt DJ, van Eldik C, Van Soelen B, Vasileiadis G, Veh J, Venter C, Viana A, Vincent P, Vink J, Voisin F, Voelk HJ, Vuillaume T, Wadiasingh Z, Wagner SJ, Wagner P, Wagner RM, White R, Wierzcholska A, Willmann P, Wörnlein A, Wouters D, Yang R, Zabalza V, Zaborov D, Zacharias M, Zdziarski AA, Zech A, Zefi F, Ziegler A, Zywucka N, Ackermann M, Ajello M, Baldini L, Barbiellini G, Bellazzini R, Blandford RD, Bonino R, Bregeon J, Bruel P, Buehler R, Caliandro GA, Cameron RA, Caragiulo M, Caraveo PA, Cavazzuti E, Cecchi C, Chiang J, Chiaro G, Ciprini S, Cohen-Tanugi J, Costanza F, Cutini S, D'Ammando F, De Palma F, Desiante R, Di Lalla N, Di Mauro M, Di Venere L, Donaggio B, Favuzzi C, Focke WB, Fusco P, Gargano F, Gasparrini D, Giglietto N, Giordano F, Giroletti M, Guillemot L, Guiriec S, Horan D, Johannesson G, Kamae T, Kensei S, Kocevski D, Larsson S, Li J, Longo F, Loparco F, Lovellette MN, Lubrano P, Maldera S, Manfreda A, Mazziotta MN, Michelson PF, Mizuno T, Monzani ME, Morselli A, Negro M, Nuss E, Orienti M, Orlando E, Paneque D, Perkins JS, Pesce-Rollins M, Piron F, Pivato G, Porter TA, Principe G, Raino S, Razzano M, Simone D, Siskind EJ, Spada F, Spinelli P, Thayer JB, Torres DF, Torresi E, Troja E, Vianello G, Wood KS (2017)
Publication Language: English
Publication Status: Published
Publication Type: Journal article, Original article
Publication year: 2017
Publisher: EDP Sciences
Book Volume: 600
Article Number: A89
DOI: 10.1051/0004-6361/201629427
Context. 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 gamma-ray energies below 100 GeV for small zenith angle observations. Such an extension of the instrument's energy range is particularly beneficial for studies of active galactic nuclei with soft spectra, as expected for those at a redshift ≥0.5. The high-frequency peaked BL Lac objects PKS 2155-304 (z = 0:116) and PG 1553+113 (0:43 < z < 0:58) are among the brightest objects in the gamma-ray sky, both showing clear signatures of gamma-ray absorption at E > 100 GeV interpreted as being due to interactions with the extragalactic background light (EBL). Aims. The aims of this work are twofold: to demonstrate the monoscopic analysis of CT5 data with a low energy threshold, and to obtain accurate measurements of the spectral energy distributions (SED) of PKS 2155-304 and PG 1553+113 near their SED peaks at energies 100 GeV. Methods. Multiple observational campaigns of PKS 2155-304 and PG 1553+113 were conducted during 2013 and 2014 using the full H.E.S.S. II instrument (CT1'5). A monoscopic analysis of the data taken with the new CT5 telescope was developed along with an investigation into the systematic uncertainties on the spectral parameters which are derived from this analysis. Results. Using the data from CT5, the energy spectra of PKS 2155-304 and PG 1553+113 were reconstructed down to conservative threshold energies of 80 GeV for PKS 2155-304, which transits near zenith, and 110 GeV for the more northern PG 1553+113. The measured spectra, well fitted in both cases by a log-parabola spectral model (with a 5.0φ statistical preference for non-zero curvature for PKS 2155-304 and 4.5φ for PG 1553+113), were found consistent with spectra derived from contemporaneous Fermi-LAT data, indicating a sharp break in the observed spectra of both sources at E 100 GeV. When corrected for EBL absorption, the intrinsic H.E.S.S. II mono and Fermi-LAT spectrum of PKS 2155-304 was found to show significant curvature. For PG 1553+113, however, no significant detection of curvature in the intrinsic spectrum could be found within statistical and systematic uncertainties.
APA:
Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F.A., Akhperjanian, A.G., Andersson, T.,... Wood, K.S. (2017). Gamma-ray blazar spectra with H.E.S.S. II mono analysis: The case of PKS 2155-304 and PG 1553+113. Astronomy & Astrophysics, 600. https://dx.doi.org/10.1051/0004-6361/201629427
MLA:
Abdalla, H., et al. "Gamma-ray blazar spectra with H.E.S.S. II mono analysis: The case of PKS 2155-304 and PG 1553+113." Astronomy & Astrophysics 600 (2017).
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