Spectral analysis and interpretation of the γ-ray emission from the starburst galaxy NGC253

Abramowski A, Acero F, Aharonian F, Akhperjanian AG, Anton G, Balzer A, Barnacka A, Becherini Y, Becker J, Bernloehr K, Birsin E, Biteau J, Bochow A, Boisson C, Bolmont J, Bordas P, Brucker J, Brun F, Brun P, Bulik T, Buesching I, Carrigan S, Casanova S, Cerruti M, Chadwick PM, Charbonnier A, Chaves RCG, Cheesebrough A, Cologna G, Conrad J, Couturier C, Dalton M, Daniel MK, Davids ID, Degrange B, Deil C, Dickinson HJ, Djannati-Atai A, Domainko W, Drury LO, Dubus G, Dutson K, Dyks J, Dyrda M, Egberts K, Eger P, Espigat P, Fallon L, Fegan S, Feinstein F, Fernandes MV, Fiasson A, Fontaine G, Foerster A, Fuessling M, Gajdus M, Gallant YA, Garrigoux T, Gast H, Gerard L, Giebels B, Glicenstein JF, Glueck B, Göring D, Grondin MH, Häffner S, Hague JD, Hahn J, Hampf D, Harris J, Hauser M, Heinz S, Heinzelmann G, Henri G, Hermann G, Hillert A, Hinton JA, Hofmann W, Hofverberg P, Holler M, Horns D, Jacholkowska A, Jahn C, Jamrozy M, Jung I, Kastendieck MA, Katarzynski K, Katz U, Kaufmann S, Khelifi B, Klochkov D, Kluzniak W, Kneiske TM, Komin N, Kosack K, Kossakowski R, Krayzel F, Laffon H, Lamanna G, Lenain JP, Lennarz D, Lohse T, Lopatin A, Lu CC, Marandon V, Marcowith A, Masbou J, Maurin G, Maxted N, Mayer M, Mccomb TJL, Medina MC, Mehault J, Moderski R, Mohamed M, Moulin E, Naumann CL, Naumann-Godo M, De Naurois M, Nedbal D, Nekrassov D, Nguyen N, Nicholas B, Niemiec J, Nolan SJ, Ohm S, Wilhelmi EDO, Opitz B, Ostrowski M, Oya I, Panter M, Arribas MP, Pekeur NW, Pelletier G, Perez J, Petrucci PO, Peyaud B, Pita S, Puehlhofer G, Punch M, Quirrenbach A, Raue M, 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, Sahakian V, Sanchez DA, Santangelo A, Schlickeiser R, Schulz A, Schwanke U, Schwarzburg S, Schwemmer S, Sheidaei F, Skilton JL, Sol H, Spengler G, Stawarz L, Steenkamp R, Stegmann C, Stinzing F, Stycz K, Sushch I, Szostek A, Tavernet JP, Terrier R, Tluczykont M, Valerius K, van Eldik C, Vasileiadis G, Venter C, Viana A, Vincent P, Voelk HJ, Volpe F, Vorobiov S, Vorster M, Wagner SJ, Ward M, White R, Wierzcholska A, Zacharias M, Zajczyk A, Zdziarski AA, Zech A, Zechlin HS (2012)

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2012

Journal

Book Volume: 757

Article Number: 158

Journal Issue: 2

DOI: 10.1088/0004-637X/757/2/158

Abstract

Very high energy (VHE; E ≥ 100 GeV) and high-energy (HE; 100 MeV ≤ E ≤ 100 GeV) data from γ-ray observations performed with the H.E.S.S. telescope array and the Fermi-LAT instrument, respectively, are analyzed in order to investigate the non-thermal processes in the starburst galaxy NGC253. The VHE γ-ray data can be described by a power law in energy with differential photon index Γ = 2.14 ± 0.18 ± 0.30 and differential flux normalization at 1TeV of F = (9.6 ± 1.5(+ 5.7, -2.9)) × 10 TeV cm s. A power-law fit to the differential HE γ-ray spectrum reveals a photon index of Γ = 2.24 ± 0.14 ± 0.03 and an integral flux between 200MeV and 200GeV of F(0.2-200 GeV) = (4.9 ± 1.0 ± 0.3) × 10 cm s. No evidence for a spectral break or turnover is found over the dynamic range of both the LAT instrument and the H.E.S.S. experiment: a combined fit of a power law to the HE and VHE γ-ray data results in a differential photon index Γ = 2.34 ± 0.03 with a p-value of 30%. The γ-ray observations indicate that at least about 20% of the energy of the cosmic rays (CRs) capable of producing hadronic interactions is channeled into pion production. The smooth alignment between the spectra in the HE and VHE γ-ray domain suggests that the same transport processes dominate in the entire energy range. Advection is most likely responsible for charged particle removal from the starburst nucleus from GeV to multiple TeV energies. In a hadronic scenario for the γ-ray production, the single overall power-law spectrum observed would therefore correspond to the mean energy spectrum produced by the ensemble of CR sources in the starburst region. © 2012. The American Astronomical Society. All rights reserved.

Authors with CRIS profile

Involved external institutions

University of Adelaide Australia (AU) Humboldt-Universität zu Berlin Germany (DE) University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot France (FR) Nicolaus Copernicus Astronomical Centre of the Polish Academy of Sciences Poland (PL) National Academy of Sciences of the Republic of Armenia (NAS RA) / Հայաստանի Հանրապետության գիտությունների ազգային ակադեմիա, ՀՀ ԳԱԱ Armenia (AM) Max-Planck-Institut für Kernphysik (MPIK) / Max Planck Institute for Nuclear Physics Germany (DE) Universität Hamburg (UHH) Germany (DE) Durham University United Kingdom (GB) University of Savoy Mont Blanc / Université Savoie Mont Blanc France (FR) École Polytechnique - Université Paris-Saclay France (FR) University of Montpellier / Université Montpellier France (FR) Université Joseph Fourier (UJF Grenoble 1) France (FR) University of Leicester United Kingdom (GB) Commissariat à l'énergie atomique France (FR) Ruprecht-Karls-Universität Heidelberg Germany (DE) Eberhard Karls Universität Tübingen Germany (DE) Jagiellonian University / Uniwersytet Jagielloński (UJ) Poland (PL) Leopold-Franzens-Universität Innsbruck / University of Innsbruck Austria (AT) Noordwes-Universiteit / North-West University South Africa (ZA) Univerzita Karlova v Praze / Charles University in Prague Czech Republic (CZ) Dublin Institute for Advanced Studies (DIAS) Ireland (IE) Ruhr-Universität Bochum (RUB) Germany (DE) Stockholm University / Stockholms universitet Sweden (SE) University of Warsaw / Uniwersytet Warszawski Poland (PL) Institute of Nuclear Physics PAN / Instytut Fizyki Jądrowej im. Henryka Niewodniczańskiego PAN Poland (PL) University of Namibia (UNAM) Namibia (NA) Nicolaus Copernicus University (NCU) / Uniwersytet Mikołaja Kopernika w Toruniu (UMK) Poland (PL)

How to cite

APA:

Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A.G., Anton, G., Balzer, A.,... Zechlin, H.-S. (2012). Spectral analysis and interpretation of the γ-ray emission from the starburst galaxy NGC253. Astrophysical Journal, 757(2). https://doi.org/10.1088/0004-637X/757/2/158

MLA:

Abramowski, A., et al. "Spectral analysis and interpretation of the γ-ray emission from the starburst galaxy NGC253." Astrophysical Journal 757.2 (2012).

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