SEARCH for GAMMA-RAY EMISSION from the COMA CLUSTER with SIX YEARS of FERMI-LAT DATA

Ackermann M, Ajello M, Albert A, Atwood WB, Baldini L, Ballet J, Barbiellini G, Bastieri D, Bechtol K, Bellazzini R, Bissaldi E, Blandford RD, Blooms ED, Bonino R, Bottacini E, Bregeon J, Bruel P, Buehler R, Caliandro GA, Cameron RA, 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, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Giglietto N, Giordano F, Giroletti M, Godfrey G, Green D, Grenier IA, Guiriec S, Hays E, Hewitt JW, Horan D, Johannesson G, Kuss M, Larsson S, Latronico L, Li J, Li L, Longo F, Loparco F, Lovellette MN, Lubrano P, Madejski GM, Maldera S, Manfreda A, Mayer M, Mazziotta MN, Michelson PF, Mitthumsiri W, Mizuno T, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nuss E, Ohsugi T, Orienti M, Orlando E, Ormes JF, Paneque D, Pesce-Rollins M, Petrosian V, Piron F, Pivato G, Porter TA, Raino S, Rando R, Razzano M, Reimer A, Reimer O, Sanchez-Conde M, Sgro C, Siskind EJ, Spada F, Spandre G, Spinelli P, Tajima H, Takahashi H, Thayer JB, Tibaldo L, Torres DF, Tosti G, Troja E, Vianello G, Wood KS, Zimmer S, Rephaeli Y (2016)

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2016

Journal

Book Volume: 819

Article Number: 149

Journal Issue: 2

DOI: 10.3847/0004-637X/819/2/149

Abstract

We present results from γ-ray observations of the Coma cluster incorporating six years of Fermi-LAT data and the newly released "Pass 8" event-level analysis. Our analysis of the region reveals low-significance residual structures within the virial radius of the cluster that are too faint for a detailed investigation with the current data. Using a likelihood approach that is free of assumptions on the spectral shape we derive upper limits on the γ-ray flux that is expected from energetic particle interactions in the cluster. We also consider a benchmark spatial and spectral template motivated by models in which the observed radio halo is mostly emission by secondary electrons. In this case, the median expected and observed upper limits for the flux above 100 are 1.7 times;10 ph cm s and 5.2 times;10 ph cm s respectively (the latter corresponds to residual emission at the level of 1.8σ). These bounds are comparable to or higher than predicted levels of hadronic gamma-ray emission in cosmic-ray (CR) models with or without reacceleration of secondary electrons, although direct comparisons are sensitive to assumptions regarding the origin and propagation mode of CRs and magnetic field properties. The minimal expected γ-ray flux from radio and star-forming galaxies within the Coma cluster is roughly an order of magnitude below the median sensitivity of our analysis.

Authors with CRIS profile

Involved external institutions

National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) Italy (IT) University of Maryland United States (USA) (US) Stanford University United States (USA) (US) École Polytechnique - Université Paris-Saclay France (FR) Italian Space Agency / Agenzia Spaziale Italiana (ASI) Italy (IT) Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC) Spain (ES) Tel Aviv University Israel (IL) Stockholm University / Stockholms universitet Sweden (SE) Deutsches Elektronen-Synchrotron DESY Germany (DE) Max-Planck-Institut für Kernphysik (MPIK) / Max Planck Institute for Nuclear Physics Germany (DE) National Institute for Nuclear Physics / Istituto Nazionale di Fisica Nucleare (INFN) Italy (IT) University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot France (FR) University of North Florida (UNF) United States (USA) (US) National Aeronautics and Space Administration (NASA) United States (USA) (US) AlbaNova University Centre / Kungliga Tekniska Högskolan AlbaNova Universitetscentrum Sweden (SE) U.S. Naval Research Laboratory United States (USA) (US) University of Iceland (UI) / Háskóli Íslands Iceland (IS) Hiroshima University Japan (JP) University of Montpellier / Université Montpellier France (FR) Clemson University United States (USA) (US) University of Wisconsin - Madison United States (USA) (US) George Mason University United States (USA) (US) University of Padua / Universita degli Studi di Padova Italy (IT) University of Udine / Università degli Studi di Udine Italy (IT) Mahidol University / มหาวิทยาลัยมหิดล Thailand (TH) 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., Albert, A., Atwood, W.B., Baldini, L., Ballet, J.,... Rephaeli, Y. (2016). SEARCH for GAMMA-RAY EMISSION from the COMA CLUSTER with SIX YEARS of FERMI-LAT DATA. Astrophysical Journal, 819(2). https://dx.doi.org/10.3847/0004-637X/819/2/149

MLA:

Ackermann, M., et al. "SEARCH for GAMMA-RAY EMISSION from the COMA CLUSTER with SIX YEARS of FERMI-LAT DATA." Astrophysical Journal 819.2 (2016).

BibTeX: Download