[Previous] | [Session 105] | [Next]
T. Wong, L. Blitz (UC Berkeley)
High-resolution BIMA observations of CO in the RSab galaxy NGC 4736 are presented. Strong emission is detected in the star-forming ring as well as in the central region, where a molecular bar is apparent. The CO data is combined with high-resolution HI maps from the VLA (Braun 1995 A&AS 114:409) to construct a complete picture of the neutral ISM in this galaxy. Both CO and HI velocity fields show strong departures from a circular rotating disk model, consistent with inflow of gas towards the ring at velocities of 20--30 km/s. We compare the gas density with the star formation rate (SFR), as traced by H-alpha and radio continuum images, to estimate local variations in the star formation efficiency (SFR per unit gas mass) and investigate the relationship between star formation and the Toomre instability parameter. We also estimate consumption timescales for the gas in the ring and consider the rate at which the ring can be replenished by gas flows.