A search for Very High Energy gamma-ray emission from Scorpius X-1 with the MAGIC telescopes
Creators: name: MAGIC Collaboration
name: Aleksić, J.
name: Alvarez, E. A.
name: Antonelli, L. A.
name: Antoranz, P.
name: Asensio, M.
name: Backes, M.
name: Barrio, J. A.
name: Bastieri, D.
name: González, J. Becerra
name: Bednarek, W.
name: Berdyugin, A.
name: Berger, K.
name: Bernardini, E.
name: Biland, A.
name: Blanch, O.
name: Bock, R. K.
name: Boller, A.
name: Bonnoli, G.
name: Bordas, P.
name: Tridon, D. Borla
name: Bosch-Ramon, V.
name: Braun, I.
name: Bretz, T.
name: Cañellas, A.
name: Carmona, E.
name: Carosi, A.
name: Colin, P.
name: Colombo, E.
name: Contreras, J. L.
name: Cortina, J.
name: Cossio, L.
name: Covino, S.
name: Dazzi, F.
name: De Angelis, A.
name: del Pozo, E. De Cea
name: De Lotto, B.
name: Mendez, C. Delgado
name: Ortega, A. Diago
name: Doert, M.
name: Domínguez, A.
name: Prester, D. Dominis
name: Dorner, D.
name: Doro, M.
name: Elsaesser, D.
name: Ferenc, D.
name: Fonseca, M. V.
name: Font, L.
name: Fruck, C.
name: López, R. J. García
name: Garczarczyk, M.
name: Garrido, D.
name: Giavitto, G.
name: Godinović, N.
name: Hadasch, D.
name: Häfner, D.
name: Herrero, A.
name: Hildebrand, D.
name: Höhne-Mönch, D.
name: Hose, J.
name: Hrupec, D.
name: Huber, B.
name: Jogler, T.
name: Klepser, S.
name: Krähenbühl, T.
name: Krause, J.
name: La Barbera, A.
name: Lelas, D.
name: Leonardo, E.
name: Lindfors, E.
name: Lombardi, S.
name: López, M.
name: Lorenz, E.
name: Makariev, M.
name: Maneva, G.
name: Mankuzhiyil, N.
name: Mannheim, K.
name: Maraschi, L.
name: Mariotti, M.
name: Martínez, M.
name: Mazin, D.
name: Meucci, M.
name: Miranda, J. M.
name: Mirzoyan, R.
name: Miyamoto, H.
name: Moldón, J.
name: Moralejo, A.
name: Munar-Adrover, P.
name: Nieto, D.
name: Nilsson, K.
name: Orito, R.
name: Oya, I.
name: Paneque, D.
name: Paoletti, R.
name: Pardo, S.
name: Paredes, J. M.
name: Partini, S.
name: Pasanen, M.
name: Pauss, F.
name: Perez-Torres, M. A.
name: Persic, M.
name: Peruzzo, L.
name: Pilia, M.
name: Pochon, J.
name: Prada, F.
name: Moroni, P. G. Prada
name: Prandini, E.
name: Puljak, I.
name: Reichardt, I.
name: Reinthal, R.
name: Rhode, W.
name: Ribó, M.
name: Rico, J.
name: Rügamer, S.
name: Saggion, A.
name: Saito, K.
name: Saito, T. Y.
name: Salvati, M.
name: Satalecka, K.
name: Scalzotto, V.
name: Scapin, V.
name: Schultz, C.
name: Schweizer, T.
name: Shayduk, M.
name: Shore, S. N.
name: Sillanpää, A.
name: Sitarek, J.
name: Sobczynska, D.
name: Spanier, F.
name: Spiro, S.
name: Stamerra, A.
name: Steinke, B.
name: Storz, J.
name: Strah, N.
name: Surić, T.
name: Takalo, L.
name: Takami, H.
name: Tavecchio, F.
name: Temnikov, P.
name: Terzić, T.
name: Tescaro, D.
name: Teshima, M.
name: Thom, M.
name: Tibolla, O.
name: Torres, D. F.
name: Treves, A.
name: Vankov, H.
name: Vogler, P.
name: Wagner, R. M.
name: Weitzel, Q.
name: Zabalza, V.
name: Zandanel, F.
name: Zanin, R.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The acceleration of particles up to GeV or higher energies in microquasars has been the subject of considerable theoretical and observational efforts in the past few years. Sco X-1 is a microquasar from which evidence of highly energetic particles in the jet has been found when it is in the so-called Horizontal Branch (HB), a state when the radio and hard X-ray fluxes are higher and a powerful relativistic jet is present. Here we present the first very high energy gamma-ray observations of Sco X-1 obtained with the MAGIC telescopes. An analysis of the whole dataset does not yield a significant signal, with 95% CL flux upper limits above 300 GeV at the level of 2.4x10^{-12} ph/cm^2/s. Simultaneous RXTE observations were conducted to search for TeV emission during particular X-ray states of the source. A selection of the gamma-ray data obtained during the HB based on the X-ray colors did not yield a signal either, with an upper limit of 3.4x10^{-12} ph/cm^2/s. These upper limits place a constraint on the maximum TeV luminosity to non-thermal X-ray luminosity of L_{VHE}/L_{ntX}&lt;0.02, that can be related to a maximum TeV luminosity to jet power ratio of L_{VHE}/L_{j}&lt;10^{-3}. Our upper limits indicate that the underlying high-energy emission physics in Sco X-1 must be inherently different from that of the hitherto detected gamma-ray binaries.
description: 5 pages, 2 figures, 2 tables. Version as published in ApJL