State transitions in the early stage of the outburst from the new X-ray transient MAXI J1305-704

We further report results from MAXI observations of the new X-ray transient MAXI J1305-704 (Sato et al. #4024). Recent MAXI/GSC data show that the one-day averaged 2-20 keV flux almost linearly increased from around April 5, 2012 (MJD=56022) to April 10, and started decreasing on April 11. The peak flux on April 10 was about 50 mCrab in the 4-10 keV band.

A preliminary spectral analysis, avoiding contamination from the nearby persistent source 4U 1254-690, shows that energy spectra obtained with MAXI/GSC are roughly described by single power-law functions with photon indices of 1.8 +/- 0.2 on April 7 and 8 (average of the 2 days), 1.9 +/- 0.2 on April 9, and 2.4 +/- 0.2 on April 10 where the column density is fixed to 2e21 cm^-2 (Kennea et al.