Issue |
A&A
Volume 551, March 2013
|
|
---|---|---|
Article Number | A94 | |
Number of page(s) | 7 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361/201220612 | |
Published online | 01 March 2013 |
H.E.S.S. observations of the binary system PSR B1259-63/LS 2883 around the 2010/2011 periastron passage
1
Universität Hamburg, Institut für
Experimentalphysik, Luruper Chaussee
149, 22761
Hamburg,
Germany
2
Laboratoire Univers et Particules de Montpellier, Université
Montpellier 2, CNRS/IN2P3, CC 72,
Place Eugène Bataillon, 34095
Montpellier Cedex 5,
France
3
Max-Planck-Institut für Kernphysik, PO Box 103980, 69029
Heidelberg,
Germany
4
Dublin Institute for Advanced Studies,
31 Fitzwilliam Place, Dublin 2,
Ireland
5
National Academy of Sciences of the Republic of Armenia, Yerevan,
Armenia
6
Yerevan Physics Institute, 2 Alikhanian Brothers St., 375036
Yerevan,
Armenia
7
Universität Erlangen-Nürnberg, Physikalisches
Institut, Erwin-Rommel-Str.
1, 91058
Erlangen,
Germany
8
University of Durham, Department of Physics,
South Road, Durham
DH1 3LE,
UK
9
DESY, 15735
Zeuthen,
Germany
10
Institut für Physik und Astronomie, Universität
Potsdam, Karl-Liebknecht-Strasse
24/25, 14476
Potsdam,
Germany
11
Nicolaus Copernicus Astronomical Center, ul. Bartycka
18, 00-716
Warsaw,
Poland
12
CEA Saclay, DSM/Irfu, 91191
Gif-Sur-Yvette Cedex,
France
13
Landessternwarte, Universität Heidelberg,
Königstuhl, 69117
Heidelberg,
Germany
14
APC, AstroParticule et Cosmologie, Université Paris Diderot,
CNRS/IN2P3, CEA/Irfu, Observatoire de Paris, Sorbonne Paris Cité, 10 rue Alice Domon et Léonie
Duquet, 75205
Paris Cedex 13,
France
15
Laboratoire Leprince-Ringuet, École Polytechnique,
CNRS/IN2P3, 91128
Palaiseau,
France
16
Institut für Theoretische Physik, Lehrstuhl IV: Weltraum und
Astrophysik, Ruhr-Universität Bochum, 44780
Bochum,
Germany
17
Institut für Physik, Humboldt-Universität zu Berlin,
Newtonstr. 15, 12489
Berlin,
Germany
18
LUTH, Observatoire de Paris, CNRS, Université Paris
Diderot, 5 place Jules
Janssen, 92190
Meudon,
France
19
LPNHE, Université Pierre et Marie Curie Paris 6, Université Denis
Diderot Paris 7,CNRS/IN2P3, 4 place
Jussieu, 75252
Paris Cedex 5,
France
20
Institut für Astronomie und Astrophysik, Universität
Tübingen, Sand 1,
72076
Tübingen,
Germany
21
Astronomical Observatory, The University of Warsaw,
Al. Ujazdowskie 4, 00-478
Warsaw,
Poland
22
Unit for Space Physics, North-West University,
Potchefstroom
2520, South
Africa
23
School of Physics, University of the Witwatersrand,
1 Jan Smuts Avenue, Braamfontein,
2050
Johannesburg, South
Africa
24
Oskar Klein Centre, Department of Physics, Stockholm University,
Albanova University Center, 10691
Stockholm,
Sweden
25
Université Bordeaux 1, CNRS/IN2P3, Centre d’Études Nucléaires de Bordeaux
Gradignan, 33175
Gradignan,
France
26
Funded by contract ERC-StG-259391 from the European Community
27
University of Namibia, Department of Physics,
Private Bag 13301, Windhoek,
Namibia
28
School of Chemistry & Physics, University of
Adelaide, 5005
Adelaide,
Australia
29
UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et
d’Astrophysique de Grenoble (IPAG) UMR 5274, 38041
Grenoble,
France
30
Department of Physics and Astronomy, The University of Leicester,
University Road, Leicester, LE1
7RH, UK
31
Instytut Fizyki Ja¸drowej PAN, ul. Radzikowskiego
152, 31-342
Kraków,
Poland
32
Institut für Astro- und Teilchenphysik,
Leopold-Franzens-Universität Innsbruck, 6020
Innsbruck,
Austria
33
Laboratoire d’Annecy-le-Vieux de Physique des Particules,
Université de Savoie, CNRS/IN2P3, 74941
Annecy-le-Vieux,
France
34
Obserwatorium Astronomiczne, Uniwersytet Jagielloński, ul. Orla
171, 30-244
Kraków,
Poland
35
Toruń Centre for Astronomy, Nicolaus Copernicus
University, ul. Gagarina
11, 87-100
Toruń,
Poland
36
Charles University, Faculty of Mathematics and Physics, Institute
of Particle and Nuclear Physics, V
Holešovičkách 2, 180
00 Prague 8, Czech Republic
37
School of Physics & Astronomy, University of
Leeds, Leeds
LS2 9JT,
UK
Received: 22 October 2012
Accepted: 8 January 2013
Aims. We present very high energy (VHE; E > 100 GeV) data from the γ-ray binary system PSR B1259-63/LS 2883 taken around its periastron passage on 15th of December 2010 with the High Energy Stereoscopic System (H.E.S.S.) of Cherenkov Telescopes. We aim to search for a possible TeV counterpart of the GeV flare detected by the Fermi LAT. In addition, we aim to study the current periastron passage in the context of previous observations taken at similar orbital phases, testing the repetitive behaviour of the source.
Methods. Observations at VHEs were conducted with H.E.S.S. from 9th to 16th of January 2011. The total dataset amounts to ~6 h of observing time. The data taken around the 2004 periastron passage were also re-analysed with the current analysis techniques in order to extend the energy spectrum above 3 TeV to fully compare observation results from 2004 and 2011.
Results. The source is detected in the 2011 data at a significance level of 11.5σ revealing an averaged integral flux above 1 TeV of (1.01 ± 0.18stat ± 0.20sys) × 10-12 cm-2 s-1. The differential energy spectrum follows a power-law shape with a spectral index Γ = 2.92 ± 0.30stat ± 0.20sys and a flux normalisation at 1 TeV of N0 = (1.95 ± 0.32stat ± 0.39sys) × 10-12 TeV-1 cm-2 s-1. The measured light curve does not show any evidence for variability of the source on the daily scale. The re-analysis of the 2004 data yields results compatible with the published ones. The differential energy spectrum measured up to ~10 TeV is consistent with a power law with a spectral index Γ = 2.81 ± 0.10stat ± 0.20sys and a flux normalisation at 1 TeV of N0 = (1.29 ± 0.08stat ± 0.26sys) × 10-12 TeV-1 cm-2 s-1.
Conclusions. The measured integral flux and the spectral shape of the 2011 data are compatible with the results obtained around previous periastron passages. The absence of variability in the H.E.S.S. data indicates that the GeV flare observed by Fermi LAT in the time period covered also by H.E.S.S. observations originates in a different physical scenario than the TeV emission. Moreover, the comparison of the new results to the results from the 2004 observations made at a similar orbital phase provides a stronger evidence of the repetitive behaviour of the source.
Key words: gamma rays: general / pulsars: individual: PSR B1259-63 / X-rays: binaries / stars: individual: LS 2883
© ESO, 2013
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