Broad-band spectral energy distribution of the X-ray transient Swift J1745−26 from outburst to quiescence

摘要: We study the X-ray transient Swift J1745-26, using observations obtained from its outburst in September 2012, up to decay towards quiescence March 2013. optical and infrared observations, through override programme at ESO/VLT with FORS2 ISAAC instruments, archival (VLT/VIRCAM), radio (Swift) build lightcurve broad-band Spectral Energy Distribution (SED) of J1745-26. show that, during also quiescence, J1745-26 SED can be adjusted, X-rays, by sum both a viscous irradiated multi-colour blackbody emitted an accretion disk, synchrotron powerlaw high energy. In domain, arises emission jet. While our fitting confirms that source remained low/hard state outburst, we determine spectral break frequency 3.1 < nu_break 3.4 x 10^14 Hz, 10^12 Hz 10^13 Hz. system is compatible absorption Av ~7.69 magnitudes, lies within distance interval D~[2.6-4.8] kpc, upper limit orbital period P_orb = 11.3 hours, companion star late-type type range K0 - M0 V, confirming low-mass binary. finally plot position on optical-infrared luminosity diagram: localization this diagram consistent staying low-hard phases.