RT Journal Article
T1 A search for very high energy gamma-ray emission from Scorpius X-1 with the MAGIC telescopes
A1 Antoranz Canales, Pedro
A1 Barrio Uña, Juan Abel
A1 Contreras González, José Luis
A1 Fonseca González, María Victoria
A1 Miranda Pantoja, José Miguel
A1 Nieto Castaño, Daniel
AB 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 data set does not yield a significant signal, with 95% CL flux upper limits above 300 GeV at the level of 2.4 x 10(-12) cm(-2) s(-1). Simultaneous RXTE observations were conducted to provide the X-ray state 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 3.4 x 10(-12) cm(-2) s(-1). These upper limits place a constraint on the maximum TeV luminosity to non-thermal X-ray luminosity of L-VHE/L-ntX less than or similar to 0.02 that can be related to a maximum TeV luminosity to jet power ratio of L-VHE/L-j less than or similar to 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.
PB IOP Publishing
SN 2041-8205
YR 2011
FD 2011-07-01
LK https://hdl.handle.net/20.500.14352/43889
UL https://hdl.handle.net/20.500.14352/43889
LA eng
NO © The American Astronomical Society. This research project has made use of data collected by NASA's RXTE. We thank the RXTE scheduling team for their help in coordinating the simultaneous observations. We also thank the Instituto de Astrofisica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The support of the German BMBF and MPG, the Italian INFN, the Swiss National Fund SNF, and the Spanish MICINN is gratefully acknowledged. This work was also supported by the Marie Curie program, by the CPAN CSD2007-00042 and MultiDark CSD2009-00064 projects of the Spanish Consolider-Ingenio 2010 programme, by grant DO02-353 of the Bulgarian NSF, by grant 127740 of the Academy of Finland, by the YIP of the Helmholtz Gemeinschaft, by the DFG Cluster of Excellence "Origin and Structure of the Universe," and by the Polish MNiSzW grant 745/N-HESS-MAGIC/2010/0.
NO German BMBF
NO MPG
NO Italian INFN
NO Swiss National Fund SNF
NO Spanish MICINN
NO Spanish Consolider-Ingenio
NO Bulgarian NSF
NO Academy of Finland
NO Helmholtz Gemeinschaft
NO DFG
NO Polish MNiSzW
DS Docta Complutense
RD 7 abr 2025