Very high energy gamma-ray observations of the galaxy clusters Abell 496 and Abell 85 with HESS

Aharonian F, Akhperjanian AG, Anton G, De Almeida UB, Bazer-Bachi AR, Becherini Y, Behera B, Bernloehr K, Boisson C, Bochow A, Borrel V, Braun IV, Brion E, Brucker J, Brun P, Buehler R, Bulik T, Buesching I, Boutelier T, Chadwick PM, Charbonnier A, Chaves RCG, Cheesebrough A, Chounet LM, Clapson AC, Coignet G, Dalton M, Daniel MK, Degrange B, Deil C, Dickinson HJ, Djannati-Atai A, Domainko W, Drury LO, Dubois F, Dubus G, Dyks J, Dyrda M, Egberts K, Emmanoulopoulos D, Espigat P, Farnier C, Feinstein F, Fiasson A, Foerster A, Fontaine G, Fuessling M, Gabici S, Gallant YA, Gerard L, Giebels B, Glicenstein JF, Glueck B, Goret P, Hauser D, Hauser M, Heinz S, Heinzelmann G, Henri G, Hermann G, Hinton JA, Hoffmann A, Hofmann W, Holleran M, Hoppe S, Horns D, Jacholkowska A, De Jager OC, Jung I, Katarzynski K, Katz U, Kaufmann S, Kendziorra E, Kerschhaggl M, Khangulyan D, Khelifi B, Keogh D, Komin N, Kosack K, Lamanna G, Lenain JP, Lohse T, Marandon V, Martin JM, Martineau-Huynh O, Marcowith A, Maurin D, Mccomb TJL, Medina MC, Moderski R, Moulin E, Naumann-Godo M, De Naurois M, Nedbal D, Nekrassov D, Niemiec J, Nolan SJ, Ohm S, Olive JF, Wilhelmi EDO, Orford KJ, Ostrowski M, Panter M, Arribas MP, Pedaletti G, Pelletier G, Petrucci PO, Pita S, Puehlhofer G, Punch M, Quirrenbach A, Raubenheimer BC, Raue M, Rayner SM, Renaud M, Rieger F, Ripken J, Rob L, Rosier-Lees S, Rowell G, Rudak B, Rulten CB, Ruppel J, Sahakian V, Santangelo A, Schlickeiser R, Schoeck FM, Schroeder R, Schwanke U, Schwarzburg S, Schwemmer S, Shalchi A, Skilton JL, Sol H, Spangler D, Stawarz L, Steenkamp R, Stegmann C, Superina G, Szostek A, Tam PH, Tavernet JP, Terrier R, Tibolla O, van Eldik C, Vasileiadis G, Venter C, Venter L, Vialle JP, Vincent P, Vivier M, Voelk HJ, Volpe F, Wagner SJ, Ward M, Zdziarski AA, Zech A (2009)

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2009

Journal

Publisher: EDP Sciences

Book Volume: 495

Pages Range: 27-35

Journal Issue: 1

DOI: 10.1051/0004-6361:200811372

Abstract

Aims. The nearby galaxy clusters Abell 496 and Abell 85 are studied in the very high-energy (VHE, 100$]]> GeV) band to investigate VHE cosmic rays (CRs) in this class of objects which are the largest gravitationally bound systems in the Universe.Methods. HESS, an array of four imaging atmospheric cherenkov telescopes (IACT), was used to observe the targets in the range of VHE gamma rays.Results. No significant gamma-ray signal is found at the respective position of the two clusters with several different source size assumptions for each target. In particular, emission regions corresponding to the high-density core, to the extension of the entire X-ray emission in these clusters, and to the very extended region where the accretion shock is expected are investigated. Upper limits are derived for the gamma-ray flux at energies 570$]]> GeV for Abell 496 and 460$]]> GeV for Abell 85.Conclusions. From the non-detection in VHE gamma rays, upper limits on the total energy of hadronic CRs in the clusters are calculated. If the cosmic-ray energy density follows the large-scale gas density profile, the limit on the fraction of energy in these non-thermal particles with respect to the total thermal energy of the intra-cluster medium (ICM) is 51% for Abell 496 and only 8% for Abell 85 due to its higher mass and higher gas density. These upper limits are compared with theoretical estimates. They predict about ∼10% of the thermal energy of the ICM in non-thermal particles. The observations presented here can constrain these predictions especially for the case of the Abell 85 cluster. © 2009 ESO.

Authors with CRIS profile

Involved external institutions

Noordwes-Universiteit / North-West University South Africa (ZA) Durham University United Kingdom (GB) Max-Planck-Institut für Kernphysik (MPIK) / Max Planck Institute for Nuclear Physics Germany (DE) Centre CEA de Saclay (Essonne) France (FR) National Center for Scientific Research / Centre national de la recherche scientifique (CNRS) France (FR) École Polytechnique - Université Paris-Saclay France (FR) University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot France (FR) Ruprecht-Karls-Universität Heidelberg Germany (DE) Université Joseph Fourier (UJF Grenoble 1) France (FR) Nicolaus Copernicus Astronomical Centre of the Polish Academy of Sciences Poland (PL) Jagiellonian University / Uniwersytet Jagielloński (UJ) Poland (PL) Institute of Nuclear Physics PAN / Instytut Fizyki Jądrowej im. Henryka Niewodniczańskiego PAN Poland (PL) University of Montpellier / Université Montpellier France (FR) Dublin Institute for Advanced Studies (DIAS) Ireland (IE) Eberhard Karls Universität Tübingen Germany (DE) Humboldt-Universität zu Berlin Germany (DE) University of Leeds United Kingdom (GB) University of Namibia (UNAM) Namibia (NA) Univerzita Karlova v Praze / Charles University in Prague Czech Republic (CZ) Nicolaus Copernicus University (NCU) / Uniwersytet Mikołaja Kopernika w Toruniu (UMK) Poland (PL) Université Toulouse III - Paul Sabatier France (FR) Ruhr-Universität Bochum (RUB) Germany (DE) Yerevan Physics Institute (YerPhI) / Երևանի Ֆիզիկայի Ինստիտուտ Armenia (AM) University of Adelaide Australia (AU) Universität Hamburg (UHH) Germany (DE)

How to cite

APA:

Aharonian, F., Akhperjanian, A.G., Anton, G., De Almeida, U.B., Bazer-Bachi, A.R., Becherini, Y.,... Zech, A. (2009). Very high energy gamma-ray observations of the galaxy clusters Abell 496 and Abell 85 with HESS. Astronomy & Astrophysics, 495(1), 27-35. https://doi.org/10.1051/0004-6361:200811372

MLA:

Aharonian, F., et al. "Very high energy gamma-ray observations of the galaxy clusters Abell 496 and Abell 85 with HESS." Astronomy & Astrophysics 495.1 (2009): 27-35.

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