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Limits to Dark Matter Annihilation Cross-Section from a Combined Analysis of MAGIC and Fermi-LAT Observations of Dwarf Satellite Galaxies

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Limits to Dark Matter Annihilation Cross-Section from a Combined Analysis of MAGIC and Fermi-LAT Observations of Dwarf Satellite Galaxies Prepared for submission to JCAP Limits to dark matter annihilation cross-section from a combined analysis of MAGIC and Fermi-LAT observations of dwarf satellite galaxies M. L. Ahnen1 S. Ansoldi2 L. A. Antonelli3 P. Antoranz4 A. Babic5 B. Banerjee6 P. Bangale7 U. Barres de Almeida7;25 J. A. Barrio8 J. Becerra Gonz´alez9;26 W. Bednarek10 E. Bernardini11;27 B. Biasuzzi2 A. Biland1 O. Blanch12 S. Bonnefoy8 G. Bonnoli3 F. Borracci7 T. Bretz13;28 E. Carmona14 A. Carosi3 A. Chatterjee6 R. Clavero9 P. Colin7 E. Colombo9 J. L. Contreras8 J. Cortina12 S. Covino3 P. Da Vela4 F. Dazzi7 A. De Angelis15 B. De Lotto2 E. de O~naWilhelmi16 C. Delgado Mendez14 F. Di Pierro3 D. Dominis Prester5 D. Dorner13 M. Doro15 S. Einecke17 D. Eisenacher Glawion13 D. Elsaesser13 A. Fern´andez-Barral12 D. Fidalgo8 M. V. Fonseca8 L. Font18 K. Frantzen17 C. Fruck7 D. Galindo19 R. J. Garc´ıaL´opez9 M. Garczarczyk11 D. Garrido Terrats18 M. Gaug18 P. Giammaria3 N. Godinovi´c5 A. Gonz´alez Mu~noz12 D. Guberman12 A. Hahn7 Y. Hanabata20 M. Hayashida20 J. Herrera9 J. Hose7 D. Hrupec5 G. Hughes1 W. Idec10 K. Kodani20 Y. Konno20 H. Kubo20 J. Kushida20 A. La Barbera3 D. Lelas5 E. Lindfors21 S. Lombardi3 F. Longo2 M. L´opez8 R. L´opez-Coto12 A. L´opez-Oramas12;29 E. Lorenz7 P. Majumdar6 M. Makariev22 K. Mallot11 G. Maneva22 M. Manganaro9 K. Mannheim13 L. Maraschi3 B. Marcote19 M. Mariotti15 M. Mart´ınez12 D. Mazin7;30 U. Menzel7 J. M. Miranda4 arXiv:1601.06590v2 [astro-ph.HE] 16 Feb 2016 R. Mirzoyan7 A. Moralejo12 E. Moretti7 D. Nakajima20 V. Neustroev21 A. Niedzwiecki10 M. Nievas Rosillo8 K. Nilsson21;31 K. Nishijima20 K. Noda7 R. Orito20 A. Overkemping17 S. Paiano15 J. Palacio12 M. Palatiello2 D. Paneque7 R. Paoletti4 J. M. Paredes19 X. Paredes-Fortuny19 M. Persic2;32 J. Poutanen21 P. G. Prada Moroni23 E. Prandini1;33 I. Puljak5 W. Rhode17 M. Rib´o19 J. Rico12;∗ J. Rodriguez Garcia7 T. Saito20 K. Satalecka8 C. Schultz15 T. Schweizer7 S. N. Shore23 A. Sillanp¨a¨a21 J. Sitarek10 I. Snidaric5 D. Sobczynska10 A. Stamerra3 T. Steinbring13 M. Strzys7 L. Takalo21 H. Takami20 F. Tavecchio3 P. Temnikov22 T. Terzi´c5 D. Tescaro9 M. Teshima7;30 J. Thaele17 D. F. Torres24 T. Toyama7 A. Treves2 V. Verguilov22 I. Vovk7 J. E. Ward12 M. Will9 M. H. Wu16 R. Zanin19 (the MAGIC Collaboration) J. Aleksi´c12;∗ M. Wood34;∗ B. Anderson35;36 E. D. Bloom34 J. Cohen-Tanugi37 A. Drlica-Wagner38 M. N. Mazziotta39 M. S´anchez-Conde35;36 L. Strigari40 1ETH Zurich, CH-8093 Zurich, Switzerland 2Universit`adi Udine, and INFN Trieste, I-33100 Udine, Italy 3INAF National Institute for Astrophysics, I-00136 Rome, Italy 4Universit`adi Siena, and INFN Pisa, I-53100 Siena, Italy 5Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka, University of Split and University of Zagreb, Croatia 6Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Salt Lake, Sector-1, Kolkata 700064, India 7Max-Planck-Institut f¨urPhysik, D-80805 M¨unchen, Germany 8Universidad Complutense, E-28040 Madrid, Spain 9Inst. de Astrof´ısicade Canarias, E-38200 La Laguna, Tenerife, Spain; Universidad de La Laguna, Dpto. Astrof´ısica,E-38206 La Laguna, Tenerife, Spain 10University ofL´od´z,PL-90236 Lodz, Poland 11Deutsches Elektronen-Synchrotron (DESY), D-15738 Zeuthen, Germany 12Institut de Fisica d'Altes Energies (IFAE), The Barcelona Institute of Science and Tech- nology, Campus UAB, 08193 Bellaterra (Barcelona), Spain 13Universit¨atW¨urzburg,D-97074 W¨urzburg,Germany 14Centro de Investigaciones Energ´eticas,Medioambientales y Tecnol´ogicas,E-28040 Madrid, Spain 15Universit`adi Padova and INFN, I-35131 Padova, Italy 16Institute for Space Sciences (CSIC/IEEC), E-08193 Barcelona, Spain 17Technische Universit¨atDortmund, D-44221 Dortmund, Germany 18Unitat de F´ısicade les Radiacions, Departament de F´ısica,and CERES-IEEC, Universitat Aut`onomade Barcelona, E-08193 Bellaterra, Spain 19Universitat de Barcelona, ICC, IEEC-UB, E-08028 Barcelona, Spain 20Japanese MAGIC Consortium, ICRR, The University of Tokyo, Department of Physics and Hakubi Center, Kyoto University, Tokai University, The University of Tokushima, KEK, Japan 21Finnish MAGIC Consortium, Tuorla Observatory, University of Turku and Department of Physics, University of Oulu, Finland 22Inst. for Nucl. Research and Nucl. Energy, BG-1784 Sofia, Bulgaria *Corresponding author. 23Universit`adi Pisa, and INFN Pisa, I-56126 Pisa, Italy 24ICREA and Institute for Space Sciences (CSIC/IEEC), E-08193 Barcelona, Spain 25now at Centro Brasileiro de Pesquisas F´ısicas(CBPF/MCTI), R. Dr. Xavier Sigaud, 150 - Urca, Rio de Janeiro - RJ, 22290-180, Brazil 26now at NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA and Department of Physics and Department of Astronomy, University of Maryland, College Park, MD 20742, USA 27Humboldt University of Berlin, Institut f¨urPhysik Newtonstr. 15, 12489 Berlin Germany 28now at Ecole polytechnique f´ed´eralede Lausanne (EPFL), Lausanne, Switzerland 29now at Laboratoire AIM, Service d'Astrophysique, DSM/IRFU, CEA/Saclay FR-91191 Gif-sur-Yvette Cedex, France 30also at Japanese MAGIC Consortium 31now at Finnish Centre for Astronomy with ESO (FINCA), Turku, Finland 32also at INAF-Trieste 33also at ISDC - Science Data Center for Astrophysics, 1290, Versoix (Geneva) 34W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stan- ford University, Stanford, CA 94305, USA 35Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden 36The Oskar Klein Centre for Cosmoparticle Physics, AlbaNova, SE-106 91 Stockholm, Swe- den 37Laboratoire Univers et Particules de Montpellier, Universit´eMontpellier, CNRS/IN2P3, Montpellier, France 38Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, IL 60510, USA 39Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy 40Texas A&M University, Department of Physics and Astronomy, College Station, TX 77843- 4242, USA E-mail: [email protected], [email protected], [email protected] Abstract. We present the first joint analysis of gamma-ray data from the MAGIC Cherenkov tele- scopes and the Fermi Large Area Telescope (LAT) to search for gamma-ray signals from dark matter annihilation in dwarf satellite galaxies. We combine 158 hours of Segue 1 observations with MAGIC with 6-year observations of 15 dwarf satellite galaxies by the Fermi-LAT. We obtain limits on the annihilation cross-section for dark matter particle masses between 10 GeV and 100 TeV { the widest mass range ever explored by a single gamma-ray analysis. These limits improve on previously published Fermi-LAT and MAGIC results by up to a factor of two at certain masses. Our new inclusive analysis approach is completely generic and can be used to perform a global, sensitivity-optimized dark matter search by combining data from present and future gamma-ray and neutrino detectors. Keywords: dark matter experiments, gamma ray experiments, neutrino experiments, dwarf galaxies Contents 1 Introduction1 2 Instruments and Observations2 2.1 The MAGIC telescopes2 2.2 The Fermi-LAT3 3 Analysis 4 3.1 Dark Matter annihilation flux4 3.2 Likelihood analysis5 4 Results 7 5 Discussion and Conclusions 11 A Comparison with previous MAGIC results 12 1 Introduction The existence of a non-baryonic, neutral and cold dark matter (DM) component in the Uni- verse is supported by an overwhelming body of observational evidence, mainly involving its gravitational effects on the dynamics of cosmic structures like galaxy clusters (first observed by Zwicky in 1933 [1]) and spiral galaxies [2,3], and on the power spectrum of temperature anisotropies of the cosmic microwave background [4,5]. Several theories beyond the Stan- dard Model postulate the existence of a new neutral, stable and weakly interacting massive particle (generically known as WIMP [6]), with mass in the TeV scale, and that could account for the measured DM relic density (e.g. [7]). A promising way to identify the nature of DM and to measure its properties is to search for the Standard Model (SM) particles produced through WIMP annihilation or decay at DM over-densities, or halos, in the local Universe. Among those SM products, gamma rays and neutrinos are the only stable neutral particles. They travel from their production sites to Earth unaffected by magnetic deflection, and as such are ideal messengers for astronomical DM searches. Current gamma-ray instruments like the Fermi Large Area Telescope (LAT)1 in space, the ground-based Cherenkov telescopes MAGIC2, H.E.S.S.3 and VERITAS4, the new-generation water Cherenkov detector HAWC5, as well as neutrino telescopes like Antares6, IceCube7, and SuperKamiokande8, are sensitive to overlapping and/or complementary DM particle mass ranges (from ∼1 GeV to ∼100 TeV). All these instruments have dedicated programs 1http://fermi.gsfc.nasa.gov 2http://magic.mpp.mpg.de 3http://www.mpi-hd.mpg.de/hfm/HESS 4http://veritas.sao.arizona.edu 5http://www.hawc-observatory.org 6http://antares.in2p3.fr 7http://icecube.wisc.edu 8http://www-sk.icrr.u-tokyo.ac.jp/sk/index-e.html { 1 { to look for WIMP signals coming from, e.g., the Galactic Center and halo [8{17], galaxy clusters [18{22], dwarf spheroidal galaxies (dSphs) [23{34] and other targets [35{37]. A natural step forward within this collective effort is the combination of data from different experiments and/or observational targets, which allows a global and sensitivity- optimized search [38]. This can be achieved in a relatively straightforward way since, for a given DM particle model, a joint likelihood function can be written as the product of the particular likelihood functions for each of the measurements/instruments. One advantage of such an approach is that the details of each experiment, such as event lists or instrument response functions (IRFs), do not need to be combined or averaged. In this paper, we present a new global analysis framework for DM searches, applicable to observations from gamma-ray and neutrino instruments, and the results of applying it to the MAGIC and Fermi-LAT observations of dSphs.
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