Abstract
A new outburst of the ultraluminous supersoft X-ray source in M101 (CXOU J140332.3+542103) was detected during a recent 9.9 ks Chandra observation on 2004 July 5. More than 200 counts was detected and the energy spectrum can be fit with an absorbed blackbody model with kT=70+/-15 eV and N_H=(2.2+/-1.7)e21 cm^-2 (90% uncertainties). The unabsorbed 0.3-7 keV luminosity is 7.4e39 erg/s (d=6.7 Mpc) and the bolometric luminosity is 2e40 erg/s (derived from the normalization).