We report on the results from the observations in the very high energy band ( VHE; GeV) of the black E = 100 g hole X- ray binary ( BHXB) Cygnus X- 1. The observations were performed with the MAGIC telescope, for a total of 40 hr during 26 nights, spanning the period between 2006 June and November. Searches for steady gamma - ray signals yielded no positive result, and upper limits to the integral flux ranging between 1% and 2% of the Crab Nebula flux, depending on the energy, have been established. We also analyzed each observation night independently, obtaining evidence of gamma- ray signals at the 4.0 j significance level ( 3.2 j after trial correction) for 154 minutes of effective on- time ( EOT) on September 24 between 20: 58 and 23: 41 UTC, coinciding with an X- ray flare seen by RXTE, Swift, and INTEGRAL. A search for faster- varying signals within a night resulted in an excess with a significance of 4.9 j ( 4.1 j after trial correction) for 79 minutes EOT between 22: 17 and 23: 41 UTC. The measured excess is compatible with a pointlike source at the position of Cygnus X- 1 and excludes the nearby radio nebula powered by its relativistic jet. The differential energy spectrum is well fitted by an unbroken power law described as dN/(dA dt dE) = ( 2.3 +/- 0.6)* 10 ( E/1TeV). This is the first experimental evidence of VHE emission from a stellar mass black hole and therefore from a confirmed accreting X- ray binary.

Very high energy gamma-ray radiation from the stellar mass black hole binary Cygnus X-1 RID B-5372-2009

SHORE, STEVEN NEIL;
2007-01-01

Abstract

We report on the results from the observations in the very high energy band ( VHE; GeV) of the black E = 100 g hole X- ray binary ( BHXB) Cygnus X- 1. The observations were performed with the MAGIC telescope, for a total of 40 hr during 26 nights, spanning the period between 2006 June and November. Searches for steady gamma - ray signals yielded no positive result, and upper limits to the integral flux ranging between 1% and 2% of the Crab Nebula flux, depending on the energy, have been established. We also analyzed each observation night independently, obtaining evidence of gamma- ray signals at the 4.0 j significance level ( 3.2 j after trial correction) for 154 minutes of effective on- time ( EOT) on September 24 between 20: 58 and 23: 41 UTC, coinciding with an X- ray flare seen by RXTE, Swift, and INTEGRAL. A search for faster- varying signals within a night resulted in an excess with a significance of 4.9 j ( 4.1 j after trial correction) for 79 minutes EOT between 22: 17 and 23: 41 UTC. The measured excess is compatible with a pointlike source at the position of Cygnus X- 1 and excludes the nearby radio nebula powered by its relativistic jet. The differential energy spectrum is well fitted by an unbroken power law described as dN/(dA dt dE) = ( 2.3 +/- 0.6)* 10 ( E/1TeV). This is the first experimental evidence of VHE emission from a stellar mass black hole and therefore from a confirmed accreting X- ray binary.
2007
Albert, J; Aliu, E; Anderhub, H; Antoranz, P; Armada, A; Baixeras, C; Barrio, Ja; Bartko, H; Bastieri, D; Becker, Jk; Bednarek, W; Berger, K; Bigongiari, C; Biland, A; Bock, Rk; Bordas, P; Bosch Ramon, V; Bretz, T; Britvitch, I; Camara, M; Carmona, E; Chilingarian, A; Coarasa, Ja; Commichau, S; Contreras, Jl; Cortina, J; Costado, Mt; Curtef, V; Danielyan, V; Dazzi, F; De Angelis, A; Delgado, C; Reyes, R; De Lotto, B; Domingo SantamariA, E; Dorner, D; Doro, M; Errando, M; Fagiolini, M; Ferenc, D; Fernandez, E; Firpo, R; Flix, J; Fonseca, Mv; Font, L; Fuchs, M; Galante, N; Garcia Lopez, Rj; Garczarczyk, M; Gaug, M; Giller, M; Goebel, F; Hakobyan, D; Hayashida, M; Hengstebeck, T; Herrero, A; Hohne, D; Hose, J; Hsu, Cc; Jacon, P; Jogler, T; Kosyra, R; Kranich, D; Kritzer, R; Laille, A; Lindfors, E; Lombardi, S; Longo, F; Lopez, J; Lopez, M; Lorenz, E; Majumdar, P; Maneva, G; Mannheim, K; Mansutti, O; Mariotti, M; Martinez, M; Mazin, D; Merck, C; Meucci, M; Meyer, M; Miranda, Jm; Mirzoyan, R; Mizobuchi, S; Moralejo, A; Nieto, D; Nilsson, K; Ninkovic, J; Ona Wilhelmi, E; Otte, N; Oya, I; Panniello, M; Paoletti, R; Paredes, Jm; Pasanen, M; Pascoli, D; Pauss, F; Pegna, R; Persic, M; Peruzzo, L; Piccioli, A; Prandini, E; Puchades, N; Raymers, A; Rhode, W; Ribo, M; Rico, J; Rissi, M; Robert, A; Rugamer, S; Saggion, A; Saito, T; Sanchez, A; Sartori, P; Scalzotto, V; Scapin, V; Schmitt, R; Schweizer, T; Shayduk, M; Shinozaki, K; Shore, STEVEN NEIL; Sidro, N; Sillanpaa, A; Sobczynska, D; Stamerra, A; Stark, Ls; Takalo, L; Temnikov, P; Tescaro, D; Teshima, M; Torres, Df; Turini, N; Vankov, H; Vitale, V; Wagner, Rm; Wibig, T; Wittek, W; Zandanel, F; Zanin, R; Zapatero, J.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/179443
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