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

H. Abdalla P. Aubert 1 Jérome Chevalier 1 A. Fiasson 1 F. Krayzel 1 G. Lamanna 1 J.P. Lees 1 G. Maurin 1 S. Rosier-Lees 1 D.A. Sanchez 1 T. Vuillaume 1 Lucas Guillemot 2, 3 Hess Collaboration Lat Collaboration J. Carr 4 J. Bolmont 5 M. Cerruti 5 R. Chalme-Calvet 5 M. Chrétien 5 C. Couturier 5 A. Jacholkowska 5 D. Kerszberg 5 M. Kieffer 5 J.-P. Lenain 5 C. Perennes 5 M. Settimo 5 J.-P. Tavernet 5 P. Vincent 5 R.C.G. Chaves 6 J. Bregeon 6 J. Cohen-Tanougi 6 E. Nuss 6 F. Piron 6 F. Brun 7 B. Condon 7 M.-H. Grondin 7 H. Laffon 7 M. Lemoine-Goumard 7 B. Degrange 8 S. Fegan 8 G. Fontaine 8 G. Giebels 8 M. Holler 8 C. Mariaud 8 M. de Naurois 8 D. Zaborov 8 F. Zefi 8 P. Bruel 8 D. Horand 8 A. Djannati-Atai 9 S. Gabici 9 L. Jouvin 9 B. Khélifi 9 A. Lemière 9 S. Pita 9 M. Punch 9 T. Tavernier 9 R. Terrier 9 Maialen Arrieta 10 Catherine Boisson 10 Olivier Hervet 10 Julien Lefaucheur 10 Cameron Rulten 10 Helene Sol 10 Andreas Zech 10
1 LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules - Laboratoire d'Annecy de Physique des Particules
2 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
3 USN - Unité Scientifique de la Station de Nançay
4 CPPM - Centre de Physique des Particules de Marseille
5 LPNHE (UMR_7585) - Laboratoire de Physique Nucléaire et de Hautes Énergies
6 LUPM - Laboratoire Univers et Particules de Montpellier
7 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
8 LLR - Laboratoire Leprince-Ringuet
9 APC (UMR_7164) - AstroParticule et Cosmologie
10 LUTH (UMR_8102) - Laboratoire Univers et Théories
Abstract : 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. 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). 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. 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. The energy spectra of PKS 2155-304 and PG 1553+113 were reconstructed down to 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 5.0 sigma statistical preference for non-zero curvature for PKS 2155-304 and 4.5 sigma 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.
Document type :
Journal articles
Complete list of metadatas

Cited literature [67 references]  Display  Hide  Download
http://hal.in2p3.fr/in2p3-01411110
Contributor : Claudine Bombar <>
Submitted on : Wednesday, November 27, 2019 - 8:23:54 AM
Last modification on : Wednesday, January 8, 2020 - 1:48:25 AM

File

aa29427-16.pdf
Publisher files allowed on an open archive

Identifiers

Collections

INSU | IN2P3 | LUTH | CPPM | MIPS | DSM-IRFU | X | CEA | X-LLR | UNIV-MONTPELLIER | CEA-DRF | LPNHE | UNIV-PARIS7 | USPC | LUPM_EMA | SU-SCIENCES | LPC2E | LUPM | LLR | CENBG | X-DEP-PHYS | LAPP | CNRS | USN | UNIV-AMU | OBSPM | UNIV-SAVOIE | UNIV-ORLEANS | PSL | APC | OSUC | IRFU-APC | UGA | UNIV-PARIS-SACLAY | SORBONNE-UNIVERSITE

Citation

H. Abdalla, P. Aubert, Jérome Chevalier, A. Fiasson, F. Krayzel, 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 and Astrophysics - A&A, EDP Sciences, 2017, 600, pp.A89. ⟨10.1051/0004-6361/201629427⟩. ⟨in2p3-01411110⟩

Export

BibTeX TEI DC DCterms EndNote

Share

Metrics

Record views

659

Files downloads

23

Contact

Informations

CCSD