Optical emission of the black hole X-ray transient MAXI J1659-152 during   quiescence
  We report on the optical detection of the black hole X-ray transient MAXI J1659-152 during its quiescent state. By using the Canada France Hawaii Telescope (CFHT), we observed MAXI J1659-152 about 7 months after the end of an X-ray outburst. The optical counterpart of MAXI J1659-152 is clearly detected with a r'-band magnitude of 23.6-23.8. The detection confirms that the optical emission of MAXI J1659-152 during quiescence is relatively bright comparing to other black hole X-ray transients. This implies that the distance to MAXI J1659-152 is 4.6-7.5 kpc for a M2 dwarf companion star, or 2.3-3.8 kpc for a M5 dwarf companion star. By comparing with other measurements, a M2 dwarf companion is more likely. 
Albert K.H. Kong (National Tsing Hua University, Taiwan)
astro-ph.HE