Detection of extended very-high-energy gamma-ray emission towards the young stellar cluster Westerlund 2

F. Aharonian; A. G. Akhperjanian; A. R. Bazer-Bachi; M. Beilicke; W. Benbow; D. Berge; K. Bernlöhr; C. Boisson; O. Bolz; V. Borrel; I. Braun; E. Brion; A. M. Brown; R. Buhler; I. Busching; T. Boutelier; S. Carrigan; P. M. Chadwick; L. M. Chounet; G. Coignet; R. Cornils; L. Costamante; B. Degrange; H. J. Dickinson; A. Djannati-Ataï; L. O'Connor-Drury; G. Dubus; K. Egberts; D. Emmanoulopoulos; P. Espigat; C. Farnier; F. Feinstein; E. Ferrero; A. Fiasson; G. Fontaine; S. Funk; M. Fuling; Y.A. Gallant; B. Giebels; J. F. Glicenstein; B. Glück; P. Goret; C. Hadjichristidis; D. Hauser; M. Hauser; G. Heinzelmann; G. Henri; G. Hermann; J. A. Hinton; A. Hoffmann; W. Hofmann; M. Holleran; S. Hoppe; D. Horns; A. Jacholkowska; O. C. de Jager; E. Kendziorra; M. Kerschhaggl; B. Khelifi; N. Komin; K. Kosack; G. Lamanna; I. J. Latham; R. Le Gallou; A. Lemiere; M. Lemoine-Goumard; T. Lohse; J. M. Martin; O. Martineau-Huynh; A. Marcowith; C. Masterson; G. Maurin; T. J. L. Mccomb; Emmanuel Moulin; M. de Maurois; D. Nedbal; S. J. Nolan; A. Noutsos; J. P. Olive; K. J. Orford; J. L. Osborne; M. Panter; G. Pelletier; P. O. Petrucci; S. Pita; G. Pühlhofer; M. Punch; S. Ranchon; B. C. Raubenheimer; M. Raue; S. M. Rayner; A. Reimer; O. Reimer; J. Ripken; L. Rob; L. Rolland; S. Rosier-Lees; G. Rowell; V. V. Sahakian; A. Santangelo; L. Sauge; S. Schlenker; R. Schlickeiser; R. Schröder; U. Schwanke; S. Schwarzburg; S. Schwemmer; A. Shalchi; H. Sol; D. Spangler; F. Spanier; R. Steenkamp; C. Stegmann; G. Superina; P. H. Tam; J. P. Tavernet; R. Terrier; M. Tluczykont; C. van Eldik; G. Vasileiadis; C. Venter; J. P. Vialle; P. Vincent; H. J. Völk; S. J. Wagner; M. Ward

doi:10.1051/0004-6361:20066950

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Detection of extended very-high-energy gamma-ray emission towards the young stellar cluster Westerlund 2

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Detection of extended very-high-energy gamma-ray emission towards the young stellar cluster Westerlund 2

F. Aharonian, A. G. Akhperjanian, A. R. Bazer-Bachi, M. Beilicke, W. Benbow, D. Berge, K. Bernlöhr, C. Boisson, O. Bolz, V. Borrel, …

Astronomy & Astrophysics - A&A, Vol.467, p.1075-1080

2007

DOI: https://doi.org/10.1051/0004-6361:20066950

Résumé

ISM: star forming regions

ISM: individual objects: HESS J1023-575

WR 20a

RCW 49 (NGC 3247

G284.3-0.3)

gamma rays: observations

Results from gamma-ray observations by the H.E.S.S. telescope array in the direction of the young stellar cluster Westerlund 2 are presented. Stereoscopic imaging of Cherenkov light emission of gamma-ray induced showers in the atmosphere is used to study the celestial region around the massive Wolf-Rayet (WR) binary WR 20a. Spectral and positional analysis is performed using standard event reconstruction techniques and parameter cuts. The detection of a new gamma-ray source is reported from H.E.S.S. observations in 2006. HESS J1023-575 is found to be coincident with the young stellar cluster Westerlund 2 in the well-known HII complex RCW 49. The source is detected with a statistical significance of more than 9 sigma, and shows extension beyond a point-like object within the H.E.S.S. point-spread function. The differential gamma-ray spectrum of the emission region is measured over approximately two orders of magnitude in flux. The spatial coincidence between HESS J1023-575 and the young open cluster Westerlund 2, hosting e.g. the massive WR binary WR 20a, requires a look into a variety of potential models to account for the observed very-high-energy (VHE) gamma-ray emission. Considered emission scenarios include emission from the colliding wind zone of WR 20a, collective stellar winds from the extraordinary ensemble of hot and massive stars in the stellar cluster Westerlund 2, diffusive shock acceleration in the wind-blown bubble itself, and supersonic winds breaking out into the interstellar medium (ISM). The observed source extension argues against a single star origin of the observed VHE emission.

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Titre: Detection of extended very-high-energy gamma-ray emission towards the young stellar cluster Westerlund 2
Créateurs - sans rôle: F. Aharonian - Max Planck Institute for Nuclear Physics
A. G. Akhperjanian
A. R. Bazer-Bachi - Centre d'étude spatiale des rayonnements
M. Beilicke - Max Planck Innovation
W. Benbow - Max Planck Institute for Nuclear Physics
D. Berge - Max Planck Institute for Nuclear Physics
K. Bernlöhr - Max Planck Institute for Nuclear Physics
C. Boisson - Centre National de la Recherche Scientifique
O. Bolz - Max Planck Institute for Nuclear Physics
V. Borrel - Université Toulouse III - Paul Sabatier
I. Braun - Max Planck Institute for Nuclear Physics
E. Brion - Commissariat à l'Énergie Atomique et aux Énergies Alternatives
A. M. Brown
R. Buhler - Max Planck Institute for Nuclear Physics
I. Busching - North-West University
T. Boutelier - Université Joseph Fourier
S. Carrigan - Max Planck Institute for Nuclear Physics
P. M. Chadwick
L. M. Chounet - Laboratoire Leprince-Ringuet
G. Coignet - Laboratoire d’Annecy de Physique des Particules
R. Cornils - Max Planck Innovation
L. Costamante - Max Planck Institute for Nuclear Physics
B. Degrange - École Polytechnique
H. J. Dickinson
A. Djannati-Ataï - APC - Astrophysique des Hautes Energies
L. O'Connor-Drury
G. Dubus - Laboratoire Leprince-Ringuet
K. Egberts - Max Planck Institute for Nuclear Physics
D. Emmanoulopoulos - Heidelberg University
P. Espigat - Université Paris Cité
C. Farnier - Laboratoire de Physique Théorique
F. Feinstein - Institut National de Physique Nucléaire et de Physique des Particules
E. Ferrero - Heidelberg University
A. Fiasson - Laboratoire de Physique Théorique
G. Fontaine - Laboratoire Leprince-Ringuet
S. Funk - Humboldt-Universität zu Berlin
M. Fuling
Y.A. Gallant - Institut National de Physique Nucléaire et de Physique des Particules
B. Giebels - Laboratoire Leprince-Ringuet
J. F. Glicenstein - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
B. Glück - Friedrich-Alexander-Universität Erlangen-Nürnberg
P. Goret - CEA Paris-Saclay
C. Hadjichristidis - Durham University
D. Hauser - Max Planck Institute for Nuclear Physics
M. Hauser - Heidelberg University
G. Heinzelmann - Universität Hamburg
G. Henri - Centre National de la Recherche Scientifique
G. Hermann - Max Planck Institute for Nuclear Physics
J. A. Hinton
A. Hoffmann - University of Tübingen
W. Hofmann - Max Planck Institute for Nuclear Physics
M. Holleran - North-West University
S. Hoppe - Max Planck Institute for Nuclear Physics
D. Horns - University of Tübingen
A. Jacholkowska - Laboratoire de Physique Théorique
O. C. de Jager
E. Kendziorra - University of Tübingen
M. Kerschhaggl - Humboldt-Universität zu Berlin
B. Khelifi - Laboratoire Leprince-Ringuet
N. Komin - Laboratoire de Physique Théorique
K. Kosack - Max Planck Institute for Nuclear Physics
G. Lamanna - Laboratoire d’Annecy de Physique des Particules
I. J. Latham
R. Le Gallou - Durham University
A. Lemiere - Université Paris Cité
M. Lemoine-Goumard - Laboratoire Leprince-Ringuet
T. Lohse - Humboldt-Universität zu Berlin
J. M. Martin - Laboratoire Univers et Théories
O. Martineau-Huynh - Laboratoire de Physique Nucléaire et de Hautes Énergies
A. Marcowith - Institut National de Physique Nucléaire et de Physique des Particules
C. Masterson - Max Planck Institute for Nuclear Physics
G. Maurin - Université Paris Cité
T. J. L. Mccomb
Emmanuel Moulin - Laboratoire de Physique Théorique
M. de Maurois - Laboratoire de Physique Nucléaire et de Hautes Énergies
D. Nedbal - Charles University
S. J. Nolan
A. Noutsos - Durham University
J. P. Olive
K. J. Orford
J. L. Osborne
M. Panter - Max Planck Institute for Nuclear Physics
G. Pelletier - Centre National de la Recherche Scientifique
P. O. Petrucci - Laboratoire d'Astrophysique de Grenoble
S. Pita - Université Paris Cité
G. Pühlhofer - Heidelberg University
M. Punch - Université Paris Cité
S. Ranchon - Laboratoire d’Annecy de Physique des Particules
B. C. Raubenheimer
M. Raue - Max Planck Society
S. M. Rayner
A. Reimer
O. Reimer
J. Ripken - Universität Hamburg
L. Rob - Charles University
L. Rolland - Commissariat à l'Énergie Atomique et aux Énergies Alternatives
S. Rosier-Lees - Laboratoire d’Annecy de Physique des Particules
G. Rowell - Max Planck Institute for Nuclear Physics
V. V. Sahakian
A. Santangelo - University of Tübingen
L. Sauge - Centre National de la Recherche Scientifique
S. Schlenker - Humboldt-Universität zu Berlin
R. Schlickeiser - Ruhr University Bochum
R. Schröder - Ruhr University Bochum
U. Schwanke - Humboldt-Universität zu Berlin
S. Schwarzburg - University of Tübingen
S. Schwemmer - Heidelberg University
A. Shalchi - Ruhr University Bochum
H. Sol - Centre National de la Recherche Scientifique
D. Spangler - Durham University
F. Spanier - Ruhr University Bochum
R. Steenkamp - University of Namibia
C. Stegmann - Friedrich-Alexander-Universität Erlangen-Nürnberg
G. Superina - École Polytechnique
P. H. Tam
J. P. Tavernet - Laboratoire de Physique Nucléaire et de Hautes Énergies
R. Terrier - Université Paris Cité
M. Tluczykont - Laboratoire Leprince-Ringuet
C. van Eldik - Max Planck Institute for Nuclear Physics
G. Vasileiadis - Laboratoire de Physique Théorique
C. Venter - North-West University
J. P. Vialle - Laboratoire d’Annecy de Physique des Particules
P. Vincent - Laboratoire de Physique Nucléaire et de Hautes Énergies
H. J. Völk
S. J. Wagner
M. Ward - Durham University
Détails de publication: Astronomy & Astrophysics - A&A, Vol.467, p.1075-1080
Identifiants: 9934628809311
Unité académique: Laboratoire Univers et Particules de Montpellier - LUPM
Langue: Anglais
Type de ressource: Article de revue scientifique
Champs locaux: in2p3-00142313