Discovery of the hard spectrum VHE gamma-ray source HESS J1641-463

A. Abramowski F. Aharonian F. Ait Benkhali A. G. Akhperjanian E. O. Angüner M. Backes S. Balenderan A. Balzer A. Barnacka Y. Becherini J. Becker Tjus D. Berge S. Bernhard K. Bernlöhr E. Birsin J. Biteau 1 M. Böttcher C. Boisson J. Bolmont 2 P. Bordas J. Bregeon F. Brun P. Brun 3 M. Bryan T. Bulik S. Carrigan S. Casanova P. M. Chadwick N. Chakraborty R. Chalme-Calvet 2 R. C. G. Chaves M. Chrétien 2 S. Colafrancesco G. Cologna J. Conrad C. Couturier 2 Y. Cui I. D. Davids B. Degrange 1 C. Deil P. Dewilt A. Djannati-Ataï 4 W. Domainko A. Donath L. O'C. Drury G. Dubus K. Dutson J. Dyks M. Dyrda T. Edwards K. Egberts P. Eger P. Espigat 4 C. Farnier S. Fegan 1 F. Feinstein 5 M. V. Fernandes D. Fernandez 5 A. Fiasson 6 G. Fontaine 1 A. Förster M. Füßling S. Gabici 4 M. Gajdus Y. A. Gallant 5 T. Garrigoux 2 G. Giavitto B. Giebels 1 J. F. Glicenstein D. Gottschall M. -H. Grondin M. Grudzińska D. Hadasch 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. Ivascenko A. Jacholkowska 2 C. Jahn M. Jamrozy M. Janiak F. Jankowsky I. Jung-Richardt M. A. Kastendieck K. Katarzyński U. Katz S. Kaufmann B. Khélifi 1 M. Kieffer 2 S. Klepser D. Klochkov W. Kluźniak D. Kolitzus Nu. Komin 6 K. Kosack S. Krakau F. Krayzel 6 P. P. Krüger H. Laffon 7 G. Lamanna 6 J. Lau J. Lefaucheur 4 V. Lefranc A. Lemière 4 M. Lemoine-Goumard 7 J. -P. Lenain 2 T. Lohse A. Lopatin C. -C. Lu V. Marandon A. Marcowith 5 R. Marx G. Maurin 6 N. Maxted M. Mayer T. J. L. Mccomb J. Méhault 5 P. J. Meintjes U. Menzler M. Meyer A. M. W. Mitchell R. Moderski M. Mohamed K. Morå E. Moulin T. Murach M. De Naurois 1 J. Niemiec S. J. Nolan L. Oakes H. Odaka S. Ohm B. Opitz M. Ostrowski I. Oya M. Panter R. D. Parsons M. Paz Arribas N. W. Pekeur G. Pelletier P. -O. Petrucci B. Peyaud S. Pita 4 H. Poon G. Pühlhofer M. Punch 4 A. Quirrenbach S. Raab I. Reichardt 4 A. Reimer O. Reimer M. Renaud 5 R. de Los Reyes F. Rieger C. Romoli S. Rosier-Lees 6 G. Rowell B. Rudak C. B. Rulten V. Sahakian D. Salek D. A. Sanchez 6 A. Santangelo R. Schlickeiser F. Schüssler A. Schulz U. Schwanke S. Schwarzburg S. Schwemmer H. Sol F. Spanier G. Spengler F. Spies {ł. } Stawarz R. Steenkamp C. Stegmann F. Stinzing K. Stycz I. Sushch J. -P. Tavernet 2 T. Tavernier 4 A. M. Taylor R. Terrier 4 M. Tluczykont C. Trichard 6 K. Valerius C. Van Eldik B. Van Soelen G. Vasileiadis 5 J. Veh C. Venter A. Viana P. Vincent 2 J. Vink 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 D. Zaborov M. Zacharias A. A. Zdziarski A. Zech H. -S. Zechlin Y. Fukui H. Sano T. Fukuda S. Yoshiike
Abstract : This letter reports the discovery of a remarkably hard spectrum source, HESS J1641-463, by the High Energy Stereoscopic System (H.E.S.S.) in the very-high energy (VHE) domain. HESS J1641-463 remained unnoticed by the usual analysis techniques due to confusion with the bright nearby source HESS J1640-465. It emerged at a significance level of 8.5 standard deviations after restricting the analysis to events with energies above 4 TeV. It shows a moderate flux level of F(E > 1 TeV) = (3.64 +/- 0.44_stat +/- 0.73_sys) x 10^-13 cm^-2s-1, corresponding to 1.8% of the Crab Nebula flux above the same energy, and a hard spectrum with a photon index of Gamma = 2.07 +/- 0.11_stat +/- 0.20_sys. It is a point-like source, although an extension up to Gaussian width of sigma = 0.05 deg cannot be discounted due to uncertainties in the H.E.S.S. PSF. The VHE gamma-ray flux of HESS J1641-463 is found to be constant over the observed period when checking time binnings from year-by-year to the 28 min exposures timescales. HESS J1641-463 is positionally coincident with the radio supernova remnant SNR G338.5+0.1. No X-ray candidate stands out as a clear association, however Chandra and XMM-Newton data reveal some potential weak counterparts. Various VHE gamma-ray production scenarios are discussed. If the emission from HESS J1641-463 is produced by cosmic ray protons colliding with the ambient gas, then their spectrum must extend up to at least a few hundred TeV. The energy released in accelerating these particles could account for the entire energy budget of the galactic cosmic ray population above a few TeV.
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Contributeur : Claudine Bombar <>
Soumis le : lundi 8 septembre 2014 - 16:30:47
Dernière modification le : mardi 26 septembre 2017 - 01:39:32

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A. Abramowski, F. Aharonian, F. Ait Benkhali, A. G. Akhperjanian, E. O. Angüner, et al.. Discovery of the hard spectrum VHE gamma-ray source HESS J1641-463. The Astrophysical journal letters, Bristol : IOP Publishing, 2014, 794, pp.L1. 〈10.1088/2041-8205/794/1/L1〉. 〈in2p3-01061876〉

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