Multi-Wavelength Study of the First Gamma-Ray Emitting Lmxb Xss J12270-4859

Fermi is discovering many new gamma-ray sources, and 1FGL J1227.9-4852 is one of them. Recent studies suggest that this source is associated with the X-ray source XSS J12270-4859 (here-after J12270), of which nature is poorly understood. In this paper, we show results of our Suzaku and RXTE X-ray observations which are partly simultaneous with near-infrared (NIR) observations using InfraRed Survey Facility (IRSF). We found that J12270 shows (1) no emission lines in the X-ray spectra, (2) unique rapid temporal variations in X-rays, and (3) almost simultaneous X-ray and NIR flares. To investigate its nature, we constructed a spectral energy distribution (SED) from radio to gamma-rays. Because of the similarity of its SED with those of other microquasars, we propose that J12270 is a microquasar with a synchrotron jet, and also the first gamma-ray emitting low-mass X-ray binary.