SEARCH FOR EXTENDED GAMMA-RAY EMISSION FROM THE VIRGO GALAXY CLUSTER WITH FERMI-LAT

Ackermann M, Ajello M, Albert A, Atwood WB, Baldini L, Barbiellini G, Bastieri D, Bechtol K, Bellazzini R, Bissaldi E, Bloom ED, Bonino R, Bottacini E, Brandt TJ, Bregeon J, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Caputo R, Caragiulo M, Caraveo PA, Casandjian JM, Cavazzuti E, Cecchi C, Charles E, Chekhtman A, Chiaro G, Ciprini S, Cohen-Tanugi J, Conrad J, Cutini S, D'Ammando F, De Angelis A, De Palma F, Desiante R, Digel SW, Di Venere L, Drell PS, Favuzzi C, Fegan SJ, Focke WB, Franckowiak A, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Giglietto N, Giordano F, Giroletti M, Glanzman T, Godfrey G, Gomez-Vargas GA, Grenier A, Guiriec S, Gustafsson M, Hewitt JW, Hill AB, Horan D, Jeltema TE, Jogler T, Johnson AS, Kuss M, Larsson S, Latronico L, Li J, Li L, Longo F, Loparco F, Lovellette MN, Lubrano P, Maldera S, Malyshev D, Manfreda A, Mayer M, Mazziotta MN, Michelson PF, Mizuno T, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nuss E, Ohsugi T, Orienti M, Orlando E, Ormes JF, Paneque D, Perkins JS, Pesce-Rollins M, Petrosian V, Piron F, Pivato G, Porter TA, Raino S, Rando R, Razzano M, Reimer A, Reimer O, Sanchez-Conde M, Schulz A, Sgro C, Siskind EJ, Spada F, Spandre G, Spinelli P, Storm E, Tajima H, Takahashi HH, Thayer JB, Torres DF, Tosti G, Troja E, Vianello G, Wood KS, Wood M, Zaharijas G, Zimmer S, Pinzke A (2015)

Publication Type: Journal article

Publication year: 2015

Journal

Book Volume: 812

Journal Issue: 2

DOI: 10.1088/0004-637X/812/2/159

Abstract

Galaxy clusters are one of the prime sites to search for dark matter (DM) annihilation signals. Depending on the substructure of the DM halo of a galaxy cluster and the cross sections for DM annihilation channels, these signals might be detectable by the latest generation of gamma-ray telescopes. Here we use three years of Fermi-Large Area Telescope data, which are the most suitable for searching for very extended emission in the vicinity of the nearby Virgo galaxy cluster. Our analysis reveals statistically significant extended emission which can be well characterized by a uniformly emitting disk profile with a radius of 3 degrees that moreover is offset from the cluster center. We demonstrate that the significance of this extended emission strongly depends on the adopted interstellar emission model (IEM) and is most likely an artifact of our incomplete description of the IEM in this region. We also search for and find new point source candidates in the region. We then derive conservative upper limits on the velocity-averaged DM pair annihilation cross section from Virgo. We take into account the potential gamma-ray flux enhancement due to DM sub-halos and its complex morphology as a merging cluster. For DM annihilating into b (b) over bar, assuming a conservative sub-halo model setup, we find limits that are between 1 and 1.5 orders of magnitude above the expectation from the thermal cross section for m(DM) <= 100 GeV. In a more optimistic scenario, we exclude similar to 3 x 10(-26)cm(3)s(-1) for m(DM)less than or similar to 40 GeV for the same channel. Finally, we derive upper limits on the gamma-ray-flux produced by hadronic cosmic-ray interactions in the inter cluster medium. We find that the volume-averaged cosmic-ray-to-thermal pressure ratio is less than similar to 6%.

Authors with CRIS profile

Involved external institutions

National Institute for Nuclear Physics / Istituto Nazionale di Fisica Nucleare (INFN) Italy (IT) University of Montpellier / Université Montpellier France (FR) Italian Space Agency / Agenzia Spaziale Italiana (ASI) Italy (IT) Stanford University United States (USA) (US) Clemson University United States (USA) (US) Deutsches Elektronen-Synchrotron DESY Germany (DE) Georg-August-Universität Göttingen Germany (DE) National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) Italy (IT) National Aeronautics and Space Administration (NASA) United States (USA) (US) University of Bari Aldo Moro / Università degli Studi di Bari Aldo Moro Italy (IT) University of California Santa Cruz United States (USA) (US) Stockholm University / Stockholms universitet Sweden (SE) University of Chicago United States (USA) (US) Hiroshima University / 広島大学 Japan (JP) George Mason University United States (USA) (US) University of Maryland, Baltimore County United States (USA) (US) University of Denver United States (USA) (US) AlbaNova University Centre / Kungliga Tekniska Högskolan AlbaNova Universitetscentrum Sweden (SE) University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot France (FR) École Polytechnique - Université Paris-Saclay France (FR) U.S. Naval Research Laboratory United States (USA) (US) Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC) Spain (ES) NYCB Real-Time Computing, Inc. United States (USA) (US) University of California Irvine United States (USA) (US) University of Padua / Universita degli Studi di Padova Italy (IT) University of Udine / Università degli Studi di Udine Italy (IT)

How to cite

APA:

Ackermann, M., Ajello, M., Albert, A., Atwood, W.B., Baldini, L., Barbiellini, G.,... Pinzke, A. (2015). SEARCH FOR EXTENDED GAMMA-RAY EMISSION FROM THE VIRGO GALAXY CLUSTER WITH FERMI-LAT. Astrophysical Journal, 812(2). https://doi.org/10.1088/0004-637X/812/2/159

MLA:

Ackermann, Markus, et al. "SEARCH FOR EXTENDED GAMMA-RAY EMISSION FROM THE VIRGO GALAXY CLUSTER WITH FERMI-LAT." Astrophysical Journal 812.2 (2015).

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