Revisiting the Westerlund 2 field with the HESS telescope array

Abramowski A, Acero F, Aharonian F, Akhperjanian AG, Anton G, Barnacka A, De Almeida UB, Bazer-Bachi AR, Becherini Y, Becker J, Behera B, Bernloehr K, Bochow A, Boisson C, Bolmont J, Bordas P, Borrel V, Brucker J, Brun F, Brun P, Bulik T, Buesching I, Boutelier T, Casanova S, Cerruti M, Chadwick PM, Charbonnier A, Chaves RCG, Cheesebrough A, Conrad J, Chounet LM, Clapson AC, Coignet G, Dalton M, Daniel MK, Davids ID, Degrange B, Deil C, Dickinson HJ, Djannati-Atai A, Domainko W, Drury LO, Dubois F, Dubus G, Dyks J, Dyrda M, Egberts K, Eger P, Espigat P, Fallon L, Farnier C, Fegan S, Feinstein F, Fernandes MV, Fiasson A, Foerster A, Fontaine G, Fuessling M, Gabici S, Gallant YA, Gerard L, Gerbig D, Giebels B, Glicenstein JF, Glueck B, Goret P, Göring D, Hague JD, Hampf D, Hauser M, Heinz S, Heinzelmann G, Henri G, Hermann G, Hinton JA, Hoffmann A, Hofmann W, Hofverberg P, Holleran M, Hoppe S, Horns D, Jacholkowska A, De Jager OC, Jahn C, Jung I, Katarzynski K, Katz U, Kaufmann S, Kerschhaggl M, Khangulyan D, Khelifi B, Keogh D, Klochkov D, Kluzniak W, Kneiske TM, Komin N, Kosack K, Kossakowski R, Lamanna G, Lenain JP, Lennarz D, Lohse T, Lu CC, Marandon V, Marcowith A, Masbou J, Maurin D, Mccomb TJL, Medina MC, Mehault J, Moderski R, Moulin E, Naumann-Godo M, De Naurois M, Nedbal D, Nekrassov D, Nguyen N, Nicholas B, Niemiec J, Nolan SJ, Ohm S, Olive JF, Wilhelmi EDO, Opitz B, Orford KJ, Ostrowski M, Panter M, Arribas MP, Pedaletti G, Pelletier G, Petrucci PO, Pita S, Puehlhofer G, Punch M, Quirrenbach A, Raue M, Rayner SM, Reimer A, Reimer O, Renaud M, De Los Reyes R, Rieger F, Ripken J, Rob L, Rosier-Lees S, Rowell G, Rudak B, Rulten CB, Ruppel J, Ryde F, Sahakian V, Santangelo A, Schlickeiser R, Schoeck FM, Schoenwald A, Schwanke U, Schwarzburg S, Schwemmer S, Shalchi A, Sushch I, Sikora M, Skilton JL, Sol H, Spengler G, Stawarz L, Steenkamp R, Stegmann C, Stinzing F, Szostek A, Tam PH, Tavernet JP, Terrier R, Tibolla O, Tluczykont M, Valerius K, van Eldik C, Vasileiadis G, Venter C, Vialle JP, Viana A, Vincent P, Vivier M, Voelk HJ, Volpe F, Vorobiov S, Wagner SJ, Ward M, Zdziarski AA, Zech A, Zechlin HS, Fukui Y, Furukawa N, Ohama A, Sano H, Dawson J, Kawamura A (2011)

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2011

Journal

Publisher: EDP Sciences

Book Volume: 525

Article Number: A46

Journal Issue: 17

DOI: 10.1051/0004-6361/201015290

Abstract

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. © 2010 ESO.

Authors with CRIS profile

Involved external institutions

Commissariat à l'énergie atomique France (FR) Université Joseph Fourier (UJF Grenoble 1) France (FR) University of Montpellier / Université Montpellier France (FR) Durham University United Kingdom (GB) Max-Planck-Institut für Kernphysik (MPIK) / Max Planck Institute for Nuclear Physics Germany (DE) École Polytechnique - Université Paris-Saclay France (FR) Eberhard Karls Universität Tübingen Germany (DE) University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot France (FR) University of Savoy Mont Blanc / Université Savoie Mont Blanc France (FR) Nicolaus Copernicus Astronomical Centre of the Polish Academy of Sciences Poland (PL) Ruprecht-Karls-Universität Heidelberg Germany (DE) Univerzita Karlova v Praze / Charles University in Prague Czech Republic (CZ) Université Toulouse III - Paul Sabatier France (FR) Universität Hamburg (UHH) Germany (DE) University of Warsaw / Uniwersytet Warszawski Poland (PL) Yerevan Physics Institute (YerPhI) / Երևանի Ֆիզիկայի Ինստիտուտ Armenia (AM) Stockholm University / Stockholms universitet Sweden (SE) Noordwes-Universiteit / North-West University South Africa (ZA) Ruhr-Universität Bochum (RUB) Germany (DE) Humboldt-Universität zu Berlin Germany (DE) Dublin Institute for Advanced Studies (DIAS) Ireland (IE) University of Leicester United Kingdom (GB) Institute of Nuclear Physics PAN / Instytut Fizyki Jądrowej im. Henryka Niewodniczańskiego PAN Poland (PL) University of Adelaide Australia (AU) Jagiellonian University / Uniwersytet Jagielloński (UJ) Poland (PL) Nicolaus Copernicus University (NCU) / Uniwersytet Mikołaja Kopernika w Toruniu (UMK) Poland (PL) Leopold-Franzens-Universität Innsbruck / University of Innsbruck Austria (AT) Royal Institute of Technology / Kungliga Tekniska Högskolan (KTH) Sweden (SE) University of Namibia (UNAM) Namibia (NA) Nagoya University / 名古屋大学 Japan (JP) University of Leeds United Kingdom (GB)

How to cite

APA:

Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A.G., Anton, G., Barnacka, A.,... Kawamura, A. (2011). Revisiting the Westerlund 2 field with the HESS telescope array. Astronomy & Astrophysics, 525(17). https://dx.doi.org/10.1051/0004-6361/201015290

MLA:

Abramowski, A., et al. "Revisiting the Westerlund 2 field with the HESS telescope array." Astronomy & Astrophysics 525.17 (2011).

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