posted on 2012-10-24, 08:55authored byA. Abramowski, F. Acero, F. Aharonian, A. G. Akhperjanian, G. Anton, A. Balzer, A. Barnacka, Y. Becherini, J. Becker, K. Bernloehr, E. Birsin, van Eldik C, R. White, B. Rudak, C. B. Rulten, V. Sahakian, D. A. Sanchez, A. Santangelo, R. Schlickeiser, A. Schulz, C. Stegmann, K. Kosack, U. Schwanke, S. Schwarzburg, G. Vasileiadis, S. Schwemmer, C. Venter, N. Maxted, F. Stinzing, K. Stycz, M. Zacharias, I. Sushch, J. Masbou, A. Zajczyk, D. Keogh, A. Viana, P. Vincent, P. Brun, H. J. Voelk, M. Holler, T. Bulik, T. Lohse, A. A. Zdziarski, J. Harris, A. Zech, H. -. S. Zechlin, H. E. S. S. Collaboration, B. Khelifi, I. Buesching, S. Carrigan, S. Casanova, D. Horns, M. Cerruti, P. M. Chadwick, M. Hauser, A. Charbonnier, A. Lopatin, R. C. G. Chaves, A. Cheesebrough, G. Cologna, D. Klochkov, J. Conrad, M. Dalton, A. Jacholkowska, M. K. Daniel, S. Heinz, I. D. Davids, B. Degrange, C. Deil, H. J. Dickinson, C. -. C. Lu, A. Djannati-Atai, W. Domainko, W. Kluzniak, L. O. Drury, de Jager OC, G. Heinzelmann, G. Dubus, K. Dutson, J. Dyks, M. Dyrda, K. Egberts, P. Eger, P. Espigat, V. Marandon, L. Fallon, T. Kneiske, G. Henri, C. Jahn, S. Fegan, F. Feinstein, M. V. Fernandes, A. Fiasson, G. Fontaine, A. Foerster, M. Fuessling, Y. A. Gallant, H. Gast, G. Hermann, A. Marcowith, M. Jamrozy, N. Komin, L. Gerard, D. Gerbig, B. Giebels, J. F. Glicenstein, B. Glueck, D. Goering, S. Haeffner, A. Hillert, J. D. Hague, J. Hahn, I. Jung, D. Hampf, M. A. Kastendieck, A. Wierzcholska, J. A. Hinton, W. Hofmann, R. Kossakowski, P. Hofverberg, F. Krayzel, F. Brun, K. Katarzynski, U. Katz, M. Mayer, S. Kaufmann, J. Brucker, T. J. L. McComb, F. Volpe, H. Laffon, G. Lamanna, J. -. P. Lenain, D. Lennarz, A. Szostek, M. C. Medina, J. Biteau, J. Mehault, F. Sheidaei, R. Moderski, M. Mohamed, E. Moulin, S. Vorobiov, C. L. Naumann, M. Naumann-Godo, de Naurois M, J. -. P. Tavernet, D. Nedbal, D. Nekrassov, J. L. Skilton, N. Nguyen, A. Bochow, B. Nicholas, J. Niemiec, S. J. Nolan, M. Vorster, S. Ohm, E. D. O. Wilhelmi, R. Terrier, B. Opitz, H. Sol, M. Ostrowski, I. Oya, M. Panter, M. P. Arribas, C. Boisson, N. W. Pekeur, G. Pelletier, S. J. Wagner, J. Perez, M. Tluczykont, G. Spengler, P. -. O. Petrucci, B. Peyaud, S. Pita, G. Puehlhofer, M. Punch, A. Quirrenbach, M. Raue, J. Bolmont, S. M. Rayner, M. Ward, L. Stawarz, K. Valerius, A. Reimer, O. Reimer, M. Renaud, de los Reyes R, F. Rieger, J. Ripken, L. Rob, S. Rosier-Lees, G. Rowell, R. Steenkamp, P. Bordas
The Carina arm region, containing the supernova remnant SNR G284.3–1.8, the high-energy (HE; E > 100 MeV) binary 1FGL J1018.6–5856 and the energetic pulsar PSR J1016–5857 and its nebula, has been observed with the H.E.S.S. telescope array. The observational coverage of the region in very-high-energy (VHE; E > 0.1 TeV) γ-rays benefits from deep exposure (40 h) of the neighboring open cluster Westerlund 2. The observations have revealed a new extended region of VHE γ-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 (Γ = 2.7 ± 0.5stat) photon index, with a differential flux at 1 TeV 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 Γ = 2.9 ± 0.4stat and differential flux at 1 TeV 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 Γ = 1.65 ± 0.08 in the center of SNR G284.3–1.8, 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 (2.9 kpc/d)2. The position of XMMU J101855.4–58564 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 γ-ray emission from HESS J1018–589 and the various potential counterparts in the Carina arm region.
History
Citation
Astronomy & Astrophysics, 2012, 541
Version
VoR (Version of Record)
Published in
Astronomy & Astrophysics
Publisher
EDP Sciences for European Southern Observatory (ESO)