FERMI LARGE AREA TELESCOPE DETECTION OF EXTENDED GAMMA-RAY EMISSION FROM THE RADIO GALAXY FORNAX A

Ackermann M, Ajello M, Baldini L, Ballet J, Barbiellini G, Bastieri D, Bellazzini R, Bissaldi E, Blandford RD, Bloom ED, Bonino R, Brandt TJ, Bregeon J, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Caragiulo M, Caraveo PA, Cavazzuti E, Cecchi C, Charles E, Chekhtman A, Cheung CC, Chiaro G, Ciprini S, Cohen JM, Cohen-Tanugi J, Costanza F, Cutini S, D'Ammando F, Davis DS, De Angelis A, De Palma F, Desiante R, Digel SW, Di Lalla N, Di Mauro M, Di Venere L, Favuzzi C, Fegan SJ, Ferrara EC, Focke WB, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Georganopoulos M, Giglietto N, Giordano F, Giroletti M, Godfrey G, Green D, Grenier IA, Guiriec S, Hays E, Hewitt JW, Hill AB, Jogler T, Johnnesson G, Kensei S, Kuss M, Larsson S, Latronico L, Li J, Li L, Longo F, Loparco F, Lubrano P, Magill JD, Maldera S, Manfreda A, Mayer M, Mazziotta MN, Mcconville W, Mcenery JE, Michelson PF, Mitthumsiri W, Mizuno T, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Negro M, Nuss E, Ohno M, Ohsugi T, Orienti M, Orlando E, Ormes JF, Paneque D, Perkins JS, Pesce-Rollins M, Piron F, Pivato G, Porter TA, Raino S, Rando R, Razzano M, Reimer A, Reimer O, Schmid J, Sgro C, Simone D, Siskind EJ, Spada F, Spandre G, Spinelli P, Stawarz L, Takahashi H, Thayer JB, Thompson DJ, Torres DF, Tosti G, Troja E, Vianello G, Wood KS, Wood M, Zimmer S (2016)

Publication Status: Published

Publication Type: Journal article

Publication year: 2016

Journal

Publisher: American Astronomical Society

Book Volume: 826

Journal Issue: 1

DOI: 10.3847/0004-637X/826/1/1

Abstract

We report the Fermi Large Area Telescope detection of extended gamma-ray emission from the lobes of the radio galaxy Fornax. A using 6.1 years of Pass. 8 data. After Centaurus. A, this is now the second example of an extended gamma-ray source attributed to a radio galaxy. Both an extended flat disk morphology and a morphology following the extended radio lobes were preferred over a point-source description, and the core contribution was constrained to be < 14% of the total gamma-ray flux. A preferred alignment of the gamma-ray elongation with the radio lobes was demonstrated by rotating the radio lobes template. We found no significant evidence for variability on similar to 0.5 year timescales. Taken together, these results strongly suggest a lobe origin for the gamma-rays. With the extended nature of the > 100 MeV gamma-ray emission established, we model the source broadband emission considering currently available total lobe radio and millimeter flux measurements, as well as X-ray detections attributed to inverse Compton (IC) emission off the cosmic microwave background (CMB). Unlike the Centaurus. A case, we find that a leptonic model involving IC scattering of CMB and extragalactic background light (EBL) photons underpredicts the gamma-ray fluxes by factors of about similar to 2-3, depending on the EBL model adopted. An additional gamma-ray spectral component is thus required, and could be due to hadronic emission arising from proton-proton collisions of cosmic rays with thermal plasma within the radio lobes.

Authors with CRIS profile

Involved external institutions

National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) Italy (IT) Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC) Spain (ES) University of Geneva / Université de Genève (UNIGE) Switzerland (CH) Mahidol University / มหาวิทยาลัยมหิดล Thailand (TH) National Aeronautics and Space Administration (NASA) United States (USA) (US) University of Maryland United States (USA) (US) University of Iceland (UI) / Háskóli Íslands Iceland (IS) University of Maryland, Baltimore County (UMBC) United States (USA) (US) École Polytechnique - Université Paris-Saclay France (FR) U.S. Naval Research Laboratory United States (USA) (US) Clemson University United States (USA) (US) University of North Florida (UNF) United States (USA) (US) Jagiellonian University / Uniwersytet Jagielloński (UJ) Poland (PL) Hiroshima University / 広島大学 Japan (JP) Stanford University United States (USA) (US) National Institute for Nuclear Physics / Istituto Nazionale di Fisica Nucleare (INFN) Italy (IT) University of Udine / Università degli Studi di Udine Italy (IT) Italian Space Agency / Agenzia Spaziale Italiana (ASI) Italy (IT) University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot France (FR) AlbaNova University Centre / Kungliga Tekniska Högskolan AlbaNova Universitetscentrum Sweden (SE) Deutsches Elektronen-Synchrotron DESY Germany (DE) University of Pisa / Università di Pisa (UniPi) Italy (IT) University of Montpellier / Université Montpellier France (FR) George Mason University United States (USA) (US) University of Padua / Universita degli Studi di Padova Italy (IT) University of California Irvine United States (USA) (US) University of Denver United States (USA) (US) NYCB Real-Time Computing, Inc. United States (USA) (US)

How to cite

APA:

Ackermann, M., Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D.,... Zimmer, S. (2016). FERMI LARGE AREA TELESCOPE DETECTION OF EXTENDED GAMMA-RAY EMISSION FROM THE RADIO GALAXY FORNAX A. Astrophysical Journal, 826(1). https://doi.org/10.3847/0004-637X/826/1/1

MLA:

Ackermann, M., et al. "FERMI LARGE AREA TELESCOPE DETECTION OF EXTENDED GAMMA-RAY EMISSION FROM THE RADIO GALAXY FORNAX A." Astrophysical Journal 826.1 (2016).

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