Discovery of extended VHE γ-ray emission from the vicinity of the young massive stellar cluster Westerlund 1
HESS Collaboration, A. Abramowski, F. Acero, F. Aharonian, A. G. Akhperjanian, G. Anton, A. Balzer, A. Barnacka, U. Barres de Almeida, Y. Becherini, J. Becker, … 展开作者
HESS Collaboration, A. Abramowski, F. Acero, F. Aharonian, A. G. Akhperjanian, G. Anton, A. Balzer, A. Barnacka, U. Barres de Almeida, Y. Becherini, J. Becker, B. Behera, K. Bernlöhr, E. Birsin, J. Biteau, A. Bochow, C. Boisson, J. Bolmont, P. Bordas, J. Brucker, F. Brun, P. Brun, T. Bulik, I. Büsching, S. Carrigan, S. Casanova, M. Cerruti, P. M. Chadwick, A. Charbonnier, R. C. G. Chaves, A. Cheesebrough, L. -M. Chounet, A. C. Clapson, G. Coignet, G. Cologna, J. Conrad, M. Dalton, M. K. Daniel, I. D. Davids, B. Degrange, C. Deil, H. J. Dickinson, A. Djannati-Ataï, W. Domainko, L. O'C. Drury, F. Dubois, G. Dubus, K. Dutson, J. Dyks, M. Dyrda, K. Egberts, P. Eger, P. Espigat, L. Fallon, C. Farnier, S. Fegan, F. Feinstein, M. V. Fernandes, A. Fiasson, G. Fontaine, A. Förster, M. Füßling, Y. A. Gallant, H. Gast, L. Gérard, D. Gerbig, B. Giebels, J. F. Glicenstein, B. Glück, P. Goret, D. Göring, S. Häffner, J. D. Hague, D. Hampf, M. Hauser, S. Heinz, G. Heinzelmann, G. Henri, G. Hermann, J. A. Hinton, A. Hoffmann, W. Hofmann, P. Hofverberg, M. Holler, D. Horns, A. Jacholkowska, O. C. de Jager, C. Jahn, M. Jamrozy, I. Jung, M. A. Kastendieck, K. Katarzynski, U. Katz, S. Kaufmann, D. Keogh, D. Khangulyan, B. Khélifi, D. Klochkov, W. Kluźniak, T. Kneiske, Nu. Komin, K. Kosack, R. Kossakowski, H. Laffon, G. Lamanna, D. Lennarz, T. Lohse, A. Lopatin, C. -C. Lu, V. Marandon, A. Marcowith, J. Masbou, D. Maurin, N. Maxted, M. Mayer, T. J. L. McComb, M. C. Medina, J. Méhault, R. Moderski, E. Moulin, C. L. Naumann, M. Naumann-Godo, M. de Naurois, D. Nedbal, D. Nekrassov, N. Nguyen, B. Nicholas, J. Niemiec, S. J. Nolan, S. Ohm, E. de Ona Wilhelmi, B. Opitz, M. Ostrowski, I. Oya, M. Panter, M. Paz Arribas, G. Pedaletti, G. Pelletier, P. -O. Petrucci, S. Pita, G. Pühlhofer, M. Punch, A. Quirrenbach, M. Raue, S. M. Rayner, A. Reimer, O. Reimer, M. Renaud, R. de los Reyes, F. Rieger, J. Ripken, L. Rob, S. Rosier-Lees, G. Rowell, B. Rudak, C. B. Rulten, J. Ruppel, V. Sahakian, D. Sanchez, A. Santangelo, R. Schlickeiser, F. M. Schöck, A. Schulz, U. Schwanke, S. Schwarzburg, S. Schwemmer, F. Sheidaei, M. Sikora, J. L. Skilton, H. Sol, G. Spengler, L. Stawarz, R. Steenkamp, C. Stegmann, F. Stinzing, K. Stycz, I. Sushch, A. Szostek, J. -P. Tavernet, R. Terrier, M. Tluczykont, K. Valerius, C. van Eldik, G. Vasileiadis, C. Venter, J. P. Vialle, A. Viana, P. Vincent, H. J. Völk, F. Volpe, S. Vorobiov, M. Vorster, S. J. Wagner, M. Ward, R. White, A. Wierzcholska, M. Zacharias, A. Zajczyk, A. A. Zdziarski, A. Zech, H. -S. Zechlin
备注：
11 pages, 6 figures, accepted for publication in A&A
Results obtained in very-high-energy (VHE; E > 100 GeV) γ-ray observations performed with the H.E.S.S. telescope array are used to investigate particle acceleration processes in the vicinity of the young massive stellar cluster Westerlund 1 (Wd 1). Imaging of Cherenkov light from γ-ray induced particle cascades in the Earth's atmosphere is used to search for VHE γ rays from the region around Wd 1. Possible catalogued counterparts are searched for and discussed in terms of morphology and energetics of the H.E.S.S. source. The detection of the degree-scale extended VHE γ-ray source HESS J1646-458 is reported based on 45 hours of H.E.S.S. observations performed between 2004 and 2008. The VHE γ-ray source is centred on the nominal position of Wd 1 and detected with a total statistical significance of ~20σ. The emission region clearly extends beyond the H.E.S.S. point-spread function (PSF). The differential energy spectrum follows a power law in energy with an index of Γ=2.19 \pm 0.08_{stat} \pm 0.20_{sys} and a flux normalisation at 1 TeV of Φ_0 = (9.0 \pm 1.4_{stat} \pm 1.8_{sys}) x 10^{-12} TeV^{-1} cm^{-2} s^{-1}. The integral flux above 0.2 TeV amounts to (5.2 \pm 0.9) x 10^{-11} cm^{-2} s^{-1}. Four objects coincident with HESS J1646-458 are discussed in the search of a counterpart, namely the magnetar CXOU J164710.2-455216, the X-ray binary 4U 1642-45, the pulsar PSR J1648-4611 and the massive stellar cluster Wd 1. In a single-source scenario, Wd 1 is favoured as site of VHE particle acceleration. Here, a hadronic parent population would be accelerated within the stellar cluster . Beside this, there is evidence for a multi-source origin, where a scenario involving PSR J1648-4611 could be viable to explain parts of the VHE γ-ray emission of HESS J1646-458.
英文摘要：
Results obtained in very-high-energy (VHE; E > 100 GeV) γ-ray observations performed with the H.E.S.S. telescope array are used to investigate particle acceleration processes in the vicinity of the young massive stellar cluster Westerlund 1 (Wd 1). Imaging of Cherenkov light from γ-ray induced particle cascades in the Earth's atmosphere is used to search for VHE γ rays from the region around Wd 1. Possible catalogued counterparts are searched for and discussed in terms of morphology and energetics of the H.E.S.S. source. The detection of the degree-scale extended VHE γ-ray source HESS J1646-458 is reported based on 45 hours of H.E.S.S. observations performed between 2004 and 2008. The VHE γ-ray source is centred on the nominal position of Wd 1 and detected with a total statistical significance of ~20σ. The emission region clearly extends beyond the H.E.S.S. point-spread function (PSF). The differential energy spectrum follows a power law in energy with an index of Γ=2.19 \pm 0.08_{stat} \pm 0.20_{sys} and a flux normalisation at 1 TeV of Φ_0 = (9.0 \pm 1.4_{stat} \pm 1.8_{sys}) x 10^{-12} TeV^{-1} cm^{-2} s^{-1}. The integral flux above 0.2 TeV amounts to (5.2 \pm 0.9) x 10^{-11} cm^{-2} s^{-1}. Four objects coincident with HESS J1646-458 are discussed in the search of a counterpart, namely the magnetar CXOU J164710.2-455216, the X-ray binary 4U 1642-45, the pulsar PSR J1648-4611 and the massive stellar cluster Wd 1. In a single-source scenario, Wd 1 is favoured as site of VHE particle acceleration. Here, a hadronic parent population would be accelerated within the stellar cluster. Beside this, there is evidence for a multi-source origin, where a scenario involving PSR J1648-4611 could be viable to explain parts of the VHE γ-ray emission of HESS J1646-458.
Extended gamma-ray emission in the vicinity of the Westerlund 1 massive star cluster and Kes 41 supernova remnant seen by the Fermi Large Area Telescope
Univ Toulouse, CNES, CNRS, IRAP（图卢兹大学，法国国家空间研究中心，法国国家科学研究中心，天体物理研究所）；Institut Supérieur de l’Aéronautique et de l’Espace (ISAE-Supaero)（高级航空与航天学院）；Max-Planck-Institut für Kernphysik（马克斯·普朗克核物理研究所）；Université Bordeaux, CNRS, LP2I Bordeaux, UMR 5797（波尔多大学，法国国家科学研究中心，波尔多强相互作用与粒子物理研究所）；INAF Osservatorio Astrofisico Arcetri（意大利国家天体物理研究所阿切特里天文台）
Probing the sensitivity of CTAO-N LSTs observations at large zenith angles to the multi-TeV gamma-ray emission from the inner 10 parsecs of the Galactic Center
