Discovery of VHE γ -rays from the BL Lacertae object PKS 0548-322

Aharonian F, Akhperjanian AG, Anton G, De Almeida UB, Bazer-Bachi AR, Becherini Y, Behera B, Benbow W, Bernloehr K, Bochow A, Boisson C, Bolmont J, Borrel V, Brucker J, Brun F, 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, 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, Emmanoulopoulos D, Espigat P, Farnier C, Feinstein F, 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, 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, Jahn C, Jung I, Katarzynski K, Katz U, Kaufmann S, Kendziorra E, Kerschhaggl M, Khangulyan D, Khelifi B, Keogh D, Kluzniak W, Kneiske TM, Komin N, Kosack K, Lamanna G, Lenain JP, Lohse T, Marandon V, Martin JM, Martineau-Huynh O, Marcowith A, Masbou J, Maurin D, Mccomb TJL, Medina MC, Moderski R, Moulin E, Naumann-Godo M, De Naurois M, Nedbal D, Nekrassov D, Nicholas B, 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, Sikora M, Skilton JL, Sol H, Spangler D, Stawarz L, Steenkamp R, Stegmann C, Stinzing F, Superina G, Szostek A, Tam PH, Tavernet JP, Terrier R, Tibolla O, Tluczykont M, 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 (2010)

Publication Language: English

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2010

Journal

Publisher: EDP Sciences

Book Volume: 521

Article Number: A69

Journal Issue: 7

DOI: 10.1051/0004-6361/200912363

Abstract

Aims. PKS 0548-322 (z = 0.069) is a "high-frequency-peaked" BL Lac object and a candidate very high energy (VHE, E > 100 GeV) γ-ray emitter, due to its high X-ray and radio flux. Observations at the VHE band provide insights into the origin of very energetic particles present in this source and the radiation processes at work. Methods. We report observations made between October 2004 and January 2008 with the HESS array, a four imaging atmospheric-Cherenkov telescopes. Contemporaneous UV and X-ray observations with the Swift satellite in November 2006 are also reported. Results. PKS 0548-322 is detected for the first time in the VHE band with HESS We measure an excess of 216 γ-rays corresponding to a significance of 5.6 standard deviations. The photon spectrum of the source is described by a power-law, with a photon index of Γ = 2.86 ± 0.34 ± 0.10 . The integral flux above 200 GeV is ∼1.3% of the flux of the Crab Nebula, and is consistent with being constant in time. Contemporaneous Swift/XRT observations reveal an X-ray flux between 2 and 10 keV of F = (2.3±0.2)×10 erg cm s, an intermediate intensity state with respect to previous observations. The spectral energy distribution can be reproduced using a simple one-zone synchrotron self Compton model, with parameters similar those observed for other sources of this type. © 2010 ESO.

Authors with CRIS profile

Involved external institutions

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

How to cite

APA:

Aharonian, F., Akhperjanian, A.G., Anton, G., De Almeida, U.B., Bazer-Bachi, A.R., Becherini, Y.,... Zech, A. (2010). Discovery of VHE γ -rays from the BL Lacertae object PKS 0548-322. Astronomy & Astrophysics, 521(7). https://doi.org/10.1051/0004-6361/200912363

MLA:

Aharonian, F., et al. "Discovery of VHE γ -rays from the BL Lacertae object PKS 0548-322." Astronomy & Astrophysics 521.7 (2010).

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