Journal article
(Original article)

Publication Details

Author(s): 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
Journal: Astrophysical Journal
Publication year: 2016
Volume: 819
Journal issue: 2
ISSN: 0004-637X
eISSN: 1538-4357


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.

FAU Authors / FAU Editors

Funk, Stefan Prof. Dr.
Lehrstuhl für Physik

External institutions with authors

AlbaNova University Centre / Kungliga Tekniska Högskolan AlbaNova Universitetscentrum
Clemson University
Deutsches Elektronen-Synchrotron DESY
École Polytechnique - Université Paris-Saclay
George Mason University
Hiroshima University
Italian Space Agency / Agenzia Spaziale Italiana (ASI)
Mahidol University / มหาวิทยาลัยมหิดล
Max-Planck-Institut für Kernphysik (MPIK) / Max Planck Institute for Nuclear Physics
National Aeronautics and Space Administration (NASA)
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
National Institute for Nuclear Physics / Istituto Nazionale di Fisica Nucleare (INFN)
NYCB Real-Time Computing, Inc.
Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC)
Stanford University
Stockholm University / Stockholms universitet
Tel Aviv University
University of California Irvine
University of Denver
University of Iceland (UI)
University of Maryland
University of Montpellier / Université Montpellier
University of North Florida (UNF)
University of Padua / Universita degli Studi di Padova
University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot
University of Udine / Università degli Studi di Udine
University of Wisconsin - Madison
U.S. Naval Research Laboratory

How to cite

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).

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).


Last updated on 2019-23-08 at 08:32