The H2S 22,0-21,1 and SO 55-44 transitions were observed simultanesously toward the starburst galaxy NGC 253 using the Submillimeter Array.<br /><br />
Two H2S emission peaks are found at positions ~ 2’ NE (30 pc) and ~5’ SW (80 pc) from the galactic center, associated with the circumnuclear disk and coinciding with the inner ring structure seen on the SiO map. SO emission is detected, weakly, only toward the NE.<br /><br />
By combining data in the literature, we estimate H2S rotational temperatures of 130 K toward the NE H2S peak and 46 K toward the SW peak, and derive H2S column densities of ~ 3 and ~1 x 10^15 cm-2 and SO column densities ~4 and > 3 x 10^14cm-2 toward the NE and SW peaks, respectively.<br /><br />
The fractional abundances, relative to molecular hydrogen, are f ~ 1-3 x 10^-8 and 4 x 10^-9 for H2S and SO, comparable with the values observed in Galactic massive star-forming cores. The H2S emission is supposed to trace the on-going star formation through hot core activity, and a rough comparison with the massive star forming region Orion KL indicates that several thousands of Orion KL-like cores may exist towards each of the H2S peaks.<br /><br />