Discovery of very high energy gamma-ray emission coincident with molecular clouds in the W28 (G6.4-0.1) field

F. Aharonian; A.G. Akhperjanian; A.R. Bazer-Bachi; B. Behera; M. Beilicke; W. Benbow; D. Berge; K. Bernlöhr; C. Boisson; O. Bolz; V. Borrel; I. Braun; E. Brion; A.M. Brown; R. Bühler; T. Bulik; I. Büsching; T. Boutelier; S. Carrigan; P.M. Chadwic; L.-M. Chounet; A.C. Clapson; G. Coignet; R. Cornils; L. Costamante; B. Degrange; H.J. Dickinson; A. Djannati-Ataï; W. Domainko; L.O'C. Drury; G. Dubus; J. Dyks; K. Egberts; D. Emmanoulopoulos; P. Espigat; C. Farnier; F. Feinstein; A. Fiasson; A. Förster; G. Fontaine; Y. Fukui; Seb. Funk; S. Funk; M. Füssling; 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. Kerschhagg; B. Khélifi; Nu. Komin; K. Kosack; G. Lamanna; I.J. Latham; R. Le Gallou; A. Lemière; M. Lemoine-Goumard; J.-P. Lenain; T. Lohse; J.M. Martin; O. Martineau-Huynh; A. Marcowith; C. Masterson; G. Maurin; T.J.L. Mccomb; R. Moderski; Y. Moriguchi; Emmanuel Moulin; M. de Naurois; D. Nedbal; S.J. Nolan; J.-P. Olive; K.J. Orford; J.L. Osborne; M. Ostrowski; M. Panter; G. Pedaletti; G. Pelletier; P.-O. Petrucci; S. Pita; G. Pühlhofer; M. Punch; S. Ranchon; B.C. Raubenheimer; M. Raue; S.M. Rayner; O. Reimer; M. Renaud; J. Ripken; L. Rob; L. Rolland; S. Rosier-Lees; G. Rowell; B. Rudak; J. Ruppel; V. Sahakian; A. Santangelo; L. Saugé; S. Schlenker; R. Schlickeiser; R. Schroder; U. Schwanke; S. Schwarzburg; S. Schwemmer; A. Shalchi; H. Sol; D. Spangler; Ł. Stawarz; R. Steenkamp; C. Stegmann; G. Superina; T. Takeuchi; P.H. Tam; J.-P. Tavernet; R. Terrier; C. van Eldik; G. Vasileiadis; C. Venter; J.P. Vialle; P. Vincent; M. Vivier; H.J. Volk; F. Volpe; S.J. Wagner; M. Ward

doi:10.1051/0004-6361:20077765

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Discovery of very high energy gamma-ray emission coincident with molecular clouds in the W28 (G6.4-0.1) field

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Discovery of very high energy gamma-ray emission coincident with molecular clouds in the W28 (G6.4-0.1) field

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

Astronomy & Astrophysics - A&A, Vol.481, pp.401-410

2008

DOI: https://doi.org/10.1051/0004-6361:20077765

Résumé

We observed the W28 field (for ~40 h) at Very High Energy (VHE) gamma-ray energies (E>0.1 TeV) with the H.E.S.S. Cherenkov telescopes. A reanalysis of EGRET E>100 MeV data was also undertaken. Results from the NANTEN 4m telescope Galactic plane survey and other CO observations have been used to study molecular clouds. We have discovered VHE gamma-ray emission (HESSJ1801-233) coincident with the northeastern boundary of W28, and a complex of sources (HESSJ1800-240A, B and C) ~0.5 deg south of W28, in the Galactic disc. The VHE differential photon spectra are well fit by pure power laws with indices Gamma~2.3 to 2.7. The NANTEN ^{12}CO(J=1-0) data reveal molecular clouds positionally associating with the VHE emission, spanning a ~15 km s^{-1} range in local standard of rest velocity. The VHE/molecular cloud association could indicate a hadronic origin for HESSJ1801-233 and HESSJ1800-240, and several cloud components in projection may contribute to the VHE emission. The clouds have components covering a broad velocity range encompassing the distance estimates for W28 (~2 kpc), and extending up to ~4 kpc. Assuming a hadronic origin, and distances of 2 and 4 kpc for cloud components, the required cosmic ray density enhancement factors (with respect to the solar value) are in the range ~10 to ~30. If situated at 2 kpc distance, such cosmic ray densities may be supplied by a SNR like W28. Additionally and/or alternatively, particle acceleration may come from several catalogued SNRs and SNR candidates, the energetic ultra compact HII region W28A2, and the HII regions M8 and M20 along with their associated open clusters. Further sub-mm observations would be recommended to probe in detail the dynamics of the molecular clouds at velocites >10 km s^{-1}, and their possible connection to W28.

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Titre: Discovery of very high energy gamma-ray emission coincident with molecular clouds in the W28 (G6.4-0.1) field
Créateurs - sans rôle: F. Aharonian - Max Planck Institute for Nuclear Physics
A.G. Akhperjanian - A. Alikhanyan National Laboratory
A.R. Bazer-Bachi - Université Toulouse III - Paul Sabatier
B. Behera - Heidelberg University
M. Beilicke - Universität Hamburg
W. Benbow - Max Planck Institute for Nuclear Physics
D. Berge - Max Planck Institute for Nuclear Physics
K. Bernlöhr - Humboldt-Universität zu Berlin
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 - Durham University
R. Bühler - Max Planck Institute for Nuclear Physics
T. Bulik - Nicolaus Copernicus Astronomical Center
I. Büsching - North-West University
T. Boutelier - Centre National de la Recherche Scientifique
S. Carrigan - Max Planck Institute for Nuclear Physics
P.M. Chadwic
L.-M. Chounet - Laboratoire Leprince-Ringuet
A.C. Clapson - Max Planck Institute for Nuclear Physics
G. Coignet - Laboratoire d’Annecy de Physique des Particules
R. Cornils - Universität Hamburg
L. Costamante - Max Planck Institute for Nuclear Physics
B. Degrange - École Polytechnique
H.J. Dickinson - Durham University
A. Djannati-Ataï - APC - Astrophysique des Hautes Energies
W. Domainko - Max Planck Institute for Nuclear Physics
L.O'C. Drury
G. Dubus - Laboratoire Leprince-Ringuet
J. Dyks - Nicolaus Copernicus Astronomical Center
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 - Université de Montpellier
A. Fiasson - Laboratoire de Physique Théorique
A. Förster - Max Planck Institute for Nuclear Physics
G. Fontaine - Laboratoire Leprince-Ringuet
Y. Fukui - Nagoya University
Seb. Funk - Humboldt-Universität zu Berlin
S. Funk - Max Planck Institute for Nuclear Physics
M. Füssling
Y.A. Gallant - Laboratoire de Physique Théorique
B. Giebels - Laboratoire Leprince-Ringuet
J.F. Glicenstein - CEA Paris-Saclay
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 - Heidelberg University
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 - North-West University
E. Kendziorra - University of Tübingen
M. Kerschhagg
B. Khélifi - Max Planck Institute for Nuclear Physics
Nu. Komin - Centre National de la Recherche Scientifique
K. Kosack - Max Planck Institute for Nuclear Physics
G. Lamanna - Institut National de Physique Nucléaire et de Physique des Particules
I.J. Latham - Durham University
R. Le Gallou - Durham University
A. Lemière - Centre National de la Recherche Scientifique
M. Lemoine-Goumard - Laboratoire Leprince-Ringuet
J.-P. Lenain - Observatoire de Paris
T. Lohse - Humboldt-Universität zu Berlin
J.M. Martin - Observatoire de Paris
O. Martineau-Huynh - Laboratoire de Physique Nucléaire et de Hautes Énergies
A. Marcowith - Laboratoire de Physique Théorique
C. Masterson - Dublin Institute For Advanced Studies
G. Maurin - Commissariat à l'Énergie Atomique et aux Énergies Alternatives
T.J.L. Mccomb - Durham University
R. Moderski - Nicolaus Copernicus Astronomical Center
Y. Moriguchi - Nagoya University
Emmanuel Moulin - Centre National de la Recherche Scientifique
M. de Naurois - Université Paris Cité
D. Nedbal - Charles University
S.J. Nolan - Durham University
J.-P. Olive - Université Toulouse III - Paul Sabatier
K.J. Orford - Durham University
J.L. Osborne - Durham University
M. Ostrowski - Jagiellonian University
M. Panter - Max Planck Institute for Nuclear Physics
G. Pedaletti - Heidelberg University
G. Pelletier - Centre National de la Recherche Scientifique
P.-O. Petrucci - Université Joseph Fourier
S. Pita - Centre National de la Recherche Scientifique
G. Pühlhofer - Heidelberg University
M. Punch - Centre National de la Recherche Scientifique
S. Ranchon - Laboratoire d’Annecy de Physique des Particules
B.C. Raubenheimer - North-West University
M. Raue
S.M. Rayner
O. Reimer
M. Renaud
J. Ripken
L. Rob
L. Rolland - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
S. Rosier-Lees - Laboratoire d’Annecy de Physique des Particules
G. Rowell
B. Rudak
J. Ruppel
V. Sahakian
A. Santangelo
L. Saugé
S. Schlenker
R. Schlickeiser
R. Schroder
U. Schwanke
S. Schwarzburg
S. Schwemmer
A. Shalchi
H. Sol - Laboratoire Univers et Théories
D. Spangler
Ł. Stawarz
R. Steenkamp
C. Stegmann
G. Superina - Laboratoire Leprince-Ringuet
T. Takeuchi
P.H. Tam
J.-P. Tavernet - Laboratoire de Physique Nucléaire et de Hautes Énergies
R. Terrier - AstroParticule et Cosmologie
C. van Eldik
G. Vasileiadis - Laboratoire de Physique Théorique
C. Venter
J.P. Vialle - Laboratoire d’Annecy de Physique des Particules
P. Vincent - Laboratoire de Physique Nucléaire et de Hautes Énergies
M. Vivier - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
H.J. Volk
F. Volpe - Laboratoire Leprince-Ringuet
S.J. Wagner
M. Ward
Détails de publication: Astronomy & Astrophysics - A&A, Vol.481, pp.401-410
Identifiants: 99153582909311
Unité académique: Université de Montpellier
Langue: English
Type de ressource: Journal article
Champs locaux: in2p3-00221478