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.; Grudzińska, M.; Häffner, S.; Hahn, J.; Harris, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hillert, A.; Hinton, J.A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; Jahn, C.; Jamrozy, M.; Janiak, M.; Jankowsky, F.; Jung, I.; Kastendieck, M.A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Khélifi, B.; Kieffer, M.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Kolitzus, D.; Komin, Nu; Kosack, K.; Krakau, S.; Krayzel, F.; Krüger, P.P.; Laffon, H.; Lamanna, G.; Lefaucheur, J.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; McComb, T.J.L.; Méhault, J.; Meintjes, P.J.; Menzler, U.; Meyer, M.; Moderski, R.; Mohamed, M.; Moulin, E.; Murach, T.; Naumann, C.L.; de Naurois, M.; Niemiec, J.; Nolan, S.J.; Oakes, L.; Odaka, H.; Ohm, S.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Parsons, R.D.; Paz Arribas, M.; Pekeur, N.W.; Pelletier, G.; Perez, J.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Poon, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Raue, M.; Reichardt, I.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Rob, L.; Romoli, C.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C.B.; Sahakian, V.; Sanchez, D.A.; Santangelo, A.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sol, H.; Spengler, G.; Spies, F.; Stawarz, Ł; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Tavernet, J.-P.; Tavernier, T.; Taylor, A.M.; Terrier, R.; Tluczykont, M.; Trichard, C.; Valerius, K.; van Eldik, C.; van Soelen, B.; Vasileiadis, G.; Venter, C.; Viana, A.; Vincent, P.; Völk, H.J.; Volpe, F.; Vorster, M.; Vuillaume, T.; Wagner, S.J.; Wagner, P.; Wagner, R.M.; Ward, M.; Weidinger, M.; Weitzel, Q.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zacharias, M.; Zdziarski, A.A.; Zech, A.; Zechlin, H.-S.; Finke, J.; Fortin, P.; Horan, D.

doi:10.1051/0004-6361/201321436

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...

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

Professor Paula Chadwick p.m.chadwick@durham.ac.uk
Head Of Department

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.

Citation

Collaboration, H., Abramowski, A., Aharonian, F., Ait Benkhali, F., Akhperjanian, A., Angüner, E., …Horan, D. (2015). The high-energy γ-ray emission of AP Librae. Astronomy & Astrophysics, 573, Article A31. https://doi.org/10.1051/0004-6361/201321436

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.
Related Public URLs	http://adsabs.harvard.edu/abs/2015A%26A...573A..31H