Naslov
A search for Very High Energy gamma-ray emission from Sco X-1 with the MAGIC telescopes

Autori
Aleksić, Jelena ; ... ; Dominis Prester, Dijana ; ... ; Ferenc, Daniel ; ... ; Godinović, Nikola ; ... ; Hrupec, Dario ; ... ; Lelas, Damir ; ... ; Puljak, Ivica ; ... ; Surić, Tihomir ; ... ; Terzić, Tomislav ; ... Zanin, R.

Izvornik
The Astrophysical journal. Supplement series (0067-0049) 735 (2011); L5-1, 5

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
acceleration of particles — X-rays: binaries — Stars: individual (Sco X-1) — Gamma rays: stars

Sažetak
He 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.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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