Discovery of VHE emission towards the Carina arm region with the H.E.S.S. telescope array: HESS J1018–589

The observational coverage with HESS of the Carina region in VHE gamma-rays benefits from deep exposure (40 h) of the neighboring open cluster Westerlund 2. The observations have revealed a new extended region of VHE gamma-ray emission. The new VHE source HESS J1018-589 shows a bright, point-like emission region positionally coincident with SNR G284.3-1.8 and 1FGL J1018.6 - 5856 and a diffuse extension towards the direction of PSR J1016-5857. A soft Gamma=2.7+-0.5 photon index, with a differential flux at 1TeV of N0=(4.2+-1.1)10^-13 TeV^-1 cm^-2 s^-1 is found for the point-like source, whereas the total emission region including the diffuse emission region is well fit by a power-law function with spectral index Gamma=2.9+-0.4 and differential flux at 1TeV of N0=(6.8+-1.6) 10^-13 TeV^-1 cm^-2 s^-1. This H.E.S.S. detection motivated follow-up X-ray observations with the XMM-Newton satellite to investigate the origin of the VHE emission. The analysis of the XMM-Newton data resulted in the discovery of a bright, non-thermal point-like source (XMMU J101855.4-58564) with a photon index of Gamma=1.65+-0.08 in the center of SNRG284.3-1.8, and a thermal, extended emission region coincident with its bright northern filament. The characteristics of this thermal emission are used to estimate the plasma density in the region as n~0.5 cm^-3(2.9kpc/d)^2. The position of XMMUJ101855.4-58564 is compatible with the position reported by the Fermi-LAT collaboration for the binary system 1FGL J1018.6-5856 and the variable Swift XRT source identified with it. The new X-ray data are used alongside archival multi-wavelength data to investigate the relationship between the VHE gamma-ray emission from HESSJ1018-589 and the various potential counterparts in the Carina arm region.

M. V. Fernandes | M. C. Medina | Nicolas Produit | T. Bulik | G. Anton | J. Conrad | U. Katz | E. Moulin | T. Lohse | T. Mccomb | W. Domainko | C. Deil | S. Rosier-Lees | A. Quirrenbach | A. Lopatin | C. Venter | M. Raue | S. Ohm | C. Stegmann | I. Davids | W. Hofmann | M. Hauser | G. Fontaine | N. Maxted | R. Schlickeiser | B. Degrange | F. Aharonian | D. Horns | D. Lennarz | Y. Gallant | S. Fegan | K. Kosack | Y. Becherini | F. Feinstein | P. Goret | M. Naumann-Godo | C. Naumann | A. Santangelo | L. Drury | S. Wagner | J. Ruppel | C. Farnier | K. Valerius | D. Khangulyan | L. Stawarz | H. Dickinson | J. Ripken | B. Opitz | M. Ward | J. Tavernet | M. Panter | A. Barnacka | B. Behera | E. Birsin | J. Biteau | C. Boisson | J. Bolmont | P. Bordas | P. Brun | S. Casanova | M. Cerruti | M. Daniel | M. Naurois | G. Dubus | J. Dyks | M. Dyrda | K. Egberts | P. Eger | A. Fiasson | B. Giebels | J. Glicenstein | G. Henri | G. Hermann | P. Hofverberg | A. Jacholkowska | M. Jamrozy | I. Jung | N. Komin | R. Kossakowski | G. Lamanna | A. Marcowith | R. Moderski | D. Nedbal | J. Niemiec | S. Nolan | M. Ostrowski | I. Oya | M. P. Arribas | P. Petrucci | S. Pita | M. Punch | A. Reimer | O. Reimer | M. Renaud | F. Rieger | L. Rob | B. Rudak | C. Rulten | V. Sahakian | A. Schulz | U. Schwanke | S. Schwarzburg | S. Schwemmer | H. Sol | R. Steenkamp | F. Stinzing | A. Szóstek | R. Terrier | M. Tluczykont | C. Eldik | G. Vasileiadis | J. Vialle | A. Viana | P. Vincent | S. Vorobiov | R. White | A. Wierzcholska | M. Zacharias | A. Zajczyk | A. Zdziarski | A. Zech | H. Volk | D. Gerbig | B. Kh'elifi | G. Rowell | G. Puhlhofer | F. Brun | R. Chaves | A. Djannati-Atai | H. Laffon | V. Marandon | F. Sheidaei | P. Chadwick | I. Sushch | S. Kaufmann | K. Bernlohr | M. Fussling | J. Hinton | M. Holler | M. Kastendieck | K. Katarzy'nski | W. Klu'zniak | E. Wilhelmi | D. Sanchez | F. Acero | S. Heinz | B. Nicholas | R. Reyes | A. Akhperjanian | A. Bochow | J. Brucker | A. Charbonnier | A. Cheesebrough | A. Clapson | M. Dalton | P. Espigat | G. Heinzelmann | A. Hoffmann | C. Jahn | D. Keogh | D. Klochkov | T. Kneiske | J. Masbou | D. Maurin | D. Nekrassov | G. Pelletier | S. Rayner | J. Skilton | F. Volpe | M. Mayer | S. Carrigan | L. Fallon | J. Hague | D. Hampf | H. Gast | H. Zechlin | O. D. Jager | A. Balzer | G. Cologna | K. Dutson | A. Forster | G. Spengler | K. Stycz | I. Busching | C. Lu | H. C. A. Abramowski | S. Haffner | J. M'ehault | M. Vorster | D. Goring | N. Nguyen | U. D. Almeida | J. Becker | L. G'erard | B. Gluck | F. Schock | G. Pedaletti1 | A. Reimer | J. Conrad | D. Sanchez | A. Schulz | R. White | M. Arribas | C.-C. Lu | R. White | S. Wagner

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