Searches for dark matter annihilation signatures in the Segue 1 satellite galaxy with the MAGIC-I telescope

/ Authors

T. M. C. J. Aleksi'c, E. Alvarez, L. A. Antonelli, P. Antoranz, M. Asensio, Michael Backes, J. Barrio, D. Bastieri, J. Gonz'alez, W. Bednarek

and 229 more authors

A. Berdyugin, K. Berger, E. Bernardini, A. Biland, O. Blanch, R. Bock, A. Boller, G. Bonnoli, D. Tridon, I. Braun, T. Bretz, A. Cañellas, E. Carmona, A. Carosi, P. Colin, E. Colombo, J. Contreras, J. Cortina, L. Cossio, S. Covino, F. Dazzi, A. Angelis, E. C. D. Pozo, B. Lotto, C. Mendez, A. Ortega, M. Doert, A. Domínguez, D. Prester, D. Dorner, M. Doro, D. Elsaesser, D. Ferenc, M. Fonseca, L. Font, C. Fruck, R. L'opez, M. Garczarczyk, D. Garrido, G. Giavitto, N. Godinovi'c, D. Hadasch, D. Hafner, A. Herrero, D. Hildebrand, D. Hohne-Monch, J. Hose, D. Hrupec, B. Huber, T. Jogler, S. Klepser, T. Krahenbuhl, J. Krause, A. Barbera, D. Lelas, E. Leonardo, E. Lindfors, S. Lombardi, M. L'opez, E. Lorenz, M. Makariev, G. Maneva, N. Mankuzhiyil, K. Mannheim, L. Maraschi, M. Mariotti, M. Mart'inez, D. Mazin, M. Meucci, J. Miranda, R. Mirzoyan, H. Miyamoto, J. Mold'on, A. Moralejo, P. Munar-Adrover, D. Nieto, K. Nilsson, R. Orito, I. Oya, S. Paiano, D. Paneque, R. Paoletti, S. Pardo, J. Paredes, S. Partini, M. Pasanen, F. Pauss, M. Pérez-Torres, M. Persic, L. Peruzzo, M. Pilia, J. Pochon, F. Prada, P. Moroni, E. Prandini, I. Puljak, I. Reichardt, R. Reinthal, W. Rhode, M. Rib'o, J. Rico, S. Rugamer, A. Saggion, K. Saito, T. Saito, M. Salvati, K. Satalecka, V. Scalzotto, V. Scapin, C. Schultz, T. Schweizer, M. Shayduk, S. Shore, A. Sillanpaa, J. Sitarek, D. Sobczynska, F. Spanier, S. Spiro, A. Stamerra, B. Steinke, J. Storz, N. Strah, T. Suri'c, L. Takalo, H. Takami, F. Tavecchio, P. Temnikov, T. Terzi'c, D. Tescaro, M. Teshima, M. Thom, O. Tibolla, D. Torres, A. Treves, H. Vankov, P. Vogler, R. Wagner, Q. Weitzel, V. Zabalza, F. Zandanel, R. Zanin, M. Fornasa, R. Essig, N. Sehgal, L. Strigari, Ifae, Edifici Cn., Campus Uab, E-08193 Bellaterra, Spain., U. Complutense, E. Madrid, I. I. F. Astrophysics, I-00136 Rome, Italy., U. Siena, I. Pisa, I-53100 Siena, Technische Universitat Dortmund, D. Dortmund, H Germany, U. Padova, Infn, I-35131 Padova, Instituto de Astrof'isica de Canarias, E. Laguna, Tenerife, D. Astrof'isica, U. L. Laguna, E. Laguna, University of L'od'z, PL-90236 Lodz, Poland, T. Observatory, U. Turku, FI-21500 Piikkio, Finland., D. Elektronen-Synchrotron, D. Zeuthen, E. Zurich, CH-8093 Switzerland, M. F. Physik, D-80805 Munchen, U. Wurzburg, D-97074 Wurzburg, U. Barcelona, E. Barcelona, U. Udine, I. Trieste, I. Udine, Institut de Ci'encies de l'Espai, Inst. de Astrof'isica de Andaluc'ia, E-18080 Granada, Croatian Magic Consortium, I. R. Bošković, University of Rijeka, University of Split, HR-10000 Zagreb, Croatia., U. Barcelona, Inst. for Nucl. Research, Nucl. Energy, BG-1784 Sofia, Bulgaria., INAF-Osservatorio Astronomico, I. Trieste, U. dell'Insubria, Como, I-22100 Como, U. Pisa, I. Pisa, Icrea, E. Barcelona, N. C. E. P. F. D. Lausanne, Lausanne, Switzerland., supported by Infn Padova, N. A. C. D. I. Energ'eticas, Medioambientales y Tecnol'ogicas, Madrid, N. Eso, MultiDark fellow, Stanford Linear Accelerator Center, Stanford, California, Usa, Kavli Institute for Astrophysics, Cosmology, Stanford University

/ Abstract

We report the results of the observation of the nearly satellite galaxy Segue 1 performed by the MAGIC-I ground-based gamma-ray telescope between November 2008 and March 2009 for a total of 43.2 hours. No significant gamma-ray emission was found above the bmkground. Differential upper limits on the grimma-ray flux are derived assuming various power-law slopes for the possible emission spectrum. Integral upper limits are also calculated for several power-law spectra and for different energy thresholds. The values are of the order of 10(-11) ph cm(-2) s(-1) above 100 GeV and 10(-12) ph cm(-2) s(-1) above 200 GeV. Segue 1 is currently considered one of the most interesting targets for indirect dark matter searches. In these terms, the upper limits have been also interpreted in the context of annihilating dark matter particles. For such purpose, we performed a grid scan over a reasonable portion of the parameter space for the minimal SuperGravity model and computed the flux upper limit for each point separately, taking fully into account the peculiar spectral features of each model. We found that in order to match the experimental upper limits with the model predictions, a minimum flux boost of 10(3) is required, and that the upper limits are quite dependent on the shape of the gamma-ray energy spectrum predicted by each specific model. Finally we compared the upper limits with the predictions of some dark matter models able to explain the PAMELA rise in the positron ratio, finding that Segue 1 data are in tension with the dark matter explanation of the PAMELA spectrum in the case of a dark matter candidate annihilating into tau(+)tau(-). A complete exclusion however is not possible due to the uncertainties in the Segue 1 astrophysical factor.

Journal: Journal of Cosmology and Astroparticle Physics

DOI: 10.1088/1475-7516/2011/06/035