%0 Journal Article %A Abramowski, A. %A Acero, F. %A Aharonian, F. %A Akhperjanian, A. G. %A Anton, G. %A Barnacka, A. %A de Almeida UB %A Bazer-Bachi, A. R. %A Becherini, Y. %A Becker, J. %A Behera, B. %A Djannati-Atai, A. %A Domainko, W. %A Glueck, B. %A Drury, L. O. %A Dubois, F. %A Hofmann, W. %A Dubus, G. %A Khangulyan, D. %A Marandon, V. %A Fiasson, A. %A Raue, M. %A Dyks, J. %A Dyrda, M. %A Egberts, K. %A Eger, P. %A Goret, P. %A Espigat, P. %A Goering, D. %A Rowell, G. %A Foerster, A. %A Fontaine, G. %A Rayner, S. M. %A Fuessling, M. %A Gabici, S. %A Holleran, M. %A Gallant, Y. A. %A Hoppe, S. %A Schwarzburg, S. %A Hague, J. D. %A Hampf, D. %A Rudak, B. %A Hauser, M. %A Sikora, M. %A Heinz, S. %A Klochkov, D. %A Heinzelmann, G. %A Kluzniak, W. %A Szostek, A. %A Horns, D. %A Jacholkowska, A. %A Schwemmer, S. %A de Jager OC %A Tluczykont, M. %A Reimer, A. %A Jahn, C. %A McComb, T. J. L. %A Jung, I. %A Medina, M. C. %A Vivier, M. %A Kneiske, T. %A Komin, N. %A Tam, P. H. %A Kosack, K. %A Zdziarski, A. A. %A Reimer, O. %A Rulten, C. B. %A Kossakowski, R. %A Lamanna, G. %A Lenain, J. -. P. %A Mehault, J. %A Bernloehr, K. %A Moderski, R. %A Moulin, E. %A Voelk, H. J. %A Naumann-Godo, M. %A Tibolla, O. %A Brucker, J. %A Ruppel, J. %A Shalchi, A. %A de Naurois M %A Nedbal, D. %A Nekrassov, D. %A Nguyen, N. %A Nicholas, B. %A Niemiec, J. %A Nolan, S. J. %A Renaud, M. %A Bochow, A. %A Ohm, S. %A Ward, M. %A Volpe, F. %A Sushch, I. %A Tavernet, J. -. P. %A Olive, J. -. F. %A Wilhelmi, E. D. O. %A Opitz, B. %A Orford, K. J. %A Wagner, S. J. %A Ostrowski, M. %A Panter, M. %A Arribas, M. P. %A Ryde, F. %A Pedaletti, G. %A Pelletier, G. %A Borrel, V. %A Boisson, C. %A Terrier, R. %A Vorobiov, S. %A Bolmont, J. %A Petrucci, P. -. O. %A Pita, S. %A Puehlhofer, G. %A Punch, M. %A Bordas, P. %A Quirrenbach, A. %A Sahakian, V. %A Fallon, L. %A de los Reyes R %A Rieger, F. %A Ripken, J. %A Rob, L. %A Skilton, J. L. %A Rosier-Lees, S. %A Sol, H. %A Gerard, L. %A Santangelo, A. %A Schlickeiser, R. %A Farnier, C. %A Schoeck, F. M. %A Schoenwald, A. %A Valerius, K. %A Schwanke, U. %A van Eldik C %A Henri, G. %A Spengler, G. %A Stawarz, L. %A Gerbig, D. %A Steenkamp, R. %A Hofverberg, P. %A Stegmann, C. %A Zech, A. %A Stinzing, F. %A Zechlin, H. -. S. %A Katarzynski, K. %A Vasileiadis, G. %A Venter, C. %A Hermann, G. %A Vialle, J. P. %A Keogh, D. %A Fegan, S. %A Viana, A. %A Brun, F. %A Vincent, P. %A Brun, P. %A Lennarz, D. %A Fukui, Y. %A Furukawa, N. %A Katz, U. %A Ohama, A. %A Maurin, D. %A Feinstein, F. %A Giebels, B. %A Sano, H. %A Dawson, J. %A Kawamura, A. %A Bulik, T. %A Buesching, I. %A Boutelier, T. %A Casanova, S. %A Lohse, T. %A Cerruti, M. %A Khelifi, B. %A Kaufmann, S. %A Glicenstein, J. F. %A Hinton, J. A. %A Chadwick, P. M. %A Charbonnier, A. %A Chaves, R. C. G. %A Cheesebrough, A. %A Conrad, J. %A Chounet, L. -. M. %A Clapson, A. C. %A Fernandes, M. V. %A Coignet, G. %A Dalton, M. %A Masbou, J. %A Lu, C. -. C. %A Hoffmann, A. %A Kerschhaggl, M. %A Daniel, M. K. %A Davids, I. D. %A Degrange, B. %A Deil, C. %A Marcowith, A. %A Dickinson, H. J. %D 2012 %T Revisiting the Westerlund 2 field with the HESS telescope array %U https://figshare.le.ac.uk/articles/journal_contribution/Revisiting_the_Westerlund_2_field_with_the_HESS_telescope_array/10113821 %2 https://figshare.le.ac.uk/ndownloader/files/18229760 %K Science & Technology %K Physical Sciences %K Astronomy & Astrophysics %K gamma rays: stars %K HII regions %K GAMMA-RAY EMISSION %K PULSAR WIND NEBULAE %K LARGE-AREA TELESCOPE %K CLUSTER WESTERLUND-2 %K X-RAY %K DISCOVERY %K GALAXY %K RADIO %K EVOLUTION %K RADIATION %X Aims. Previous observations with the HESS telescope array revealed the existence of extended very-high-energy (VHE; E > 100 GeV) γ-ray emission, HESS J1023–575, coincident with the young stellar cluster Westerlund 2. At the time of discovery, the origin of the observed emission was not unambiguously identified, and follow-up observations have been performed to further investigate the nature of this γ-ray source. Methods. The Carina region towards the open cluster Westerlund 2 has been re-observed, increasing the total exposure to 45.9 h. The combined dataset includes 33 h of new data and now permits a search for energy-dependent morphology and detailed spectroscopy. Results. A new, hard spectrum VHE γ-ray source, HESS J1026–582, was discovered with a statistical significance of 7σ. It is positionally coincident with the Fermi LAT pulsar PSR J1028–5819. The positional coincidence and radio/γ-ray characteristics of the LAT pulsar favors a scenario where the TeV emission originates from a pulsar wind nebula. The nature of HESS J1023–575 is discussed in light of the deep HESS observations and recent multi-wavelength discoveries, including the Fermi LAT pulsar PSR J1022–5746 and giant molecular clouds in the region. Despite the improved VHE dataset, a clear identification of the object responsible for the VHE emission from HESS J1023–575 is not yet possible, and contribution from the nearby high-energy pulsar and/or the open cluster remains a possibility. %I University of Leicester