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The high-energy γ-ray emission of AP Librae

Collaboration, H.E.S.S.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A.G.; Angüner, E.; Anton, G.; Backes, M.; Balenderan, S.; Balzer, A.; Barnacka, A.; Becherini, Y.; Becker Tjus, J.; Bernlöhr, K.; Birsin, E.; Bissaldi, E.; Biteau, J.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Carrigan, S.; Casanova, S.; Chadwick, P.M.; Chalme-Calvet, R.; Chaves, R.C.G.; Cheesebrough, A.; Chrétien, M.; Colafrancesco, S.; Cologna, G.; Conrad, J.; Couturier, C.; Cui, Y.; Dalton, M.; Daniel, M.K.; Davids, I.D.; Degrange, B.; Deil, C.; deWilt, P.; Dickinson, H.J.; Djannati-Ataï, A.; Domainko, W.; O'C. Drury, L.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Edwards, T.; Egberts, K.; Eger, P.; Espigat, P.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M.V.; Fernandez, D.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gajdus, M.; Gallant, Y.A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J.F.; Grondin, M.-H.; Grudzi...

The high-energy γ-ray emission of AP Librae Thumbnail


Authors

H.E.S.S. Collaboration

A. Abramowski

F. Aharonian

F. Ait Benkhali

A.G. Akhperjanian

E. Angüner

G. Anton

M. Backes

S. Balenderan

A. Balzer

A. Barnacka

Y. Becherini

J. Becker Tjus

K. Bernlöhr

E. Birsin

E. Bissaldi

J. Biteau

M. Böttcher

C. Boisson

J. Bolmont

P. Bordas

J. Brucker

F. Brun

P. Brun

T. Bulik

S. Carrigan

S. Casanova

R. Chalme-Calvet

R.C.G. Chaves

A. Cheesebrough

M. Chrétien

S. Colafrancesco

G. Cologna

J. Conrad

C. Couturier

Y. Cui

M. Dalton

M.K. Daniel

I.D. Davids

B. Degrange

C. Deil

P. deWilt

H.J. Dickinson

A. Djannati-Ataï

W. Domainko

L. O'C. Drury

G. Dubus

K. Dutson

J. Dyks

M. Dyrda

T. Edwards

K. Egberts

P. Eger

P. Espigat

C. Farnier

S. Fegan

F. Feinstein

M.V. Fernandes

D. Fernandez

A. Fiasson

G. Fontaine

A. Förster

M. Füßling

M. Gajdus

Y.A. Gallant

T. Garrigoux

G. Giavitto

B. Giebels

J.F. Glicenstein

M.-H. Grondin

M. Grudzińska

S. Häffner

J. Hahn

J. Harris

G. Heinzelmann

G. Henri

G. Hermann

O. Hervet

A. Hillert

J.A. Hinton

W. Hofmann

P. Hofverberg

M. Holler

D. Horns

A. Jacholkowska

C. Jahn

M. Jamrozy

M. Janiak

F. Jankowsky

I. Jung

M.A. Kastendieck

K. Katarzyński

U. Katz

S. Kaufmann

B. Khélifi

M. Kieffer

S. Klepser

D. Klochkov

W. Kluźniak

T. Kneiske

D. Kolitzus

Nu Komin

K. Kosack

S. Krakau

F. Krayzel

P.P. Krüger

H. Laffon

G. Lamanna

J. Lefaucheur

A. Lemière

M. Lemoine-Goumard

J.-P. Lenain

T. Lohse

A. Lopatin

C.-C. Lu

V. Marandon

A. Marcowith

R. Marx

G. Maurin

N. Maxted

M. Mayer

T.J.L. McComb

J. Méhault

P.J. Meintjes

U. Menzler

M. Meyer

R. Moderski

M. Mohamed

E. Moulin

T. Murach

C.L. Naumann

M. de Naurois

J. Niemiec

S.J. Nolan

L. Oakes

H. Odaka

S. Ohm

E. de Oña Wilhelmi

B. Opitz

M. Ostrowski

I. Oya

M. Panter

R.D. Parsons

M. Paz Arribas

N.W. Pekeur

G. Pelletier

J. Perez

P.-O. Petrucci

B. Peyaud

S. Pita

H. Poon

G. Pühlhofer

M. Punch

A. Quirrenbach

S. Raab

M. Raue

I. Reichardt

A. Reimer

O. Reimer

M. Renaud

R. de los Reyes

F. Rieger

L. Rob

C. Romoli

S. Rosier-Lees

G. Rowell

B. Rudak

C.B. Rulten

V. Sahakian

D.A. Sanchez

A. Santangelo

R. Schlickeiser

F. Schüssler

A. Schulz

U. Schwanke

S. Schwarzburg

S. Schwemmer

H. Sol

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

M. Tluczykont

C. Trichard

K. Valerius

C. van Eldik

B. van Soelen

G. Vasileiadis

C. Venter

A. Viana

P. Vincent

H.J. Völk

F. Volpe

M. Vorster

T. Vuillaume

S.J. Wagner

P. Wagner

R.M. Wagner

M. Ward

M. Weidinger

Q. Weitzel

R. White

A. Wierzcholska

P. Willmann

A. Wörnlein

D. Wouters

R. Yang

V. Zabalza

M. Zacharias

A.A. Zdziarski

A. Zech

H.-S. Zechlin

J. Finke

P. Fortin

D. Horan



Abstract

The γ-ray spectrum of the low-frequency-peaked BL Lac (LBL) object AP Librae is studied, following the discovery of very-high-energy (VHE; E> 100 GeV) γ-ray emission up to the TeV range by the H.E.S.S. experiment. This makes AP Librae one of the few VHE emitters of the LBL type. The measured spectrum yields a flux of (8.8 ± 1.5stat ± 1.8sys) × 10-12 cm-2 s-1 above 130 GeV and a spectral index of Γ = 2.65 ± 0.19stat ± 0.20sys. This study also makes use of Fermi-LAT  observations in the high energy (HE, E> 100 MeV) range, providing the longest continuous light curve (5 years) ever published on this source. The source underwent a flaring event between MJD 56 306–56 376 in the HE range, with a flux increase of a factor of 3.5 in the 14 day bin light curve and no significant variation in spectral shape with respect to the low-flux state. While the H.E.S.S.  and (low state) Fermi-LAT fluxes are in good agreement where they overlap, a spectral curvature between the steep VHE spectrum and the Fermi-LAT  spectrum is observed. The maximum of the γ-ray emission in the spectral energy distribution is located below the GeV energy range.

Journal Article Type Article
Acceptance Date Oct 20, 2014
Publication Date Jan 1, 2015
Deposit Date Apr 15, 2015
Publicly Available Date Apr 22, 2015
Journal Astronomy and astrophysics.
Print ISSN 0004-6361
Electronic ISSN 1432-0746
Publisher EDP Sciences
Peer Reviewed Peer Reviewed
Volume 573
Article Number A31
DOI https://doi.org/10.1051/0004-6361/201321436
Keywords Galaxies: active, BL Lacertae objects: individual: AP Librae, Gamma rays: galaxies.
Public URL https://durham-repository.worktribe.com/output/1410172
Related Public URLs http://adsabs.harvard.edu/abs/2015A%26A...573A..31H

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Copyright Statement
Reproduced with permission from Astronomy & Astrophysics, © ESO, 2014.





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