Title: Ionized gas observation toward a nearby starburst galaxy NGC 253

Abstract:
Hydrogen recombination line is a fundamental probe to look into properties of ionized gas in 
galaxies. In particular, recombination lines in millimeter and sub-millimeter wavebands are 
suitable tool to investigate ionized gas in starburst. Now, ALMA''s superb sensitivity make it 
possible to carry out observations of the lines in reasonable time.
In this presentation, we will report outcome from analysis of hydrogen recombination line data 
toward NGC 253 with ALMA. The emission was successfully imaged in the central region of 
NGC 253 with a spatial resolution of few dozens of parsecs. It turned out ionized gas velocity 
field at the galaxy center considerably differ from that of molecular gas. The velocity field 
suggests existence of outflowing or inflowing ionized gas.