Connecting Transitions in Galaxy Properties to Refueling

Understand

We relate transitions in galaxy structure and gas content to refueling, here defined to include both the external gas accretion and the internal gas processing needed to renew reservoirs for star formation.

• We analyze two z=0 data sets: a high-quality ~200-galaxy sample (the Nearby Field Galaxy Survey, data release herein) and a volume-limited ~3000-galaxy sample with reprocessed archival data.
• Both reach down to baryonic masses ~10^9Msun and span void-to-cluster environments.
• Two mass-dependent transitions are evident: (i) below the "gas-richness threshold" scale (V~125km/s), gas-dominated quasi-bulgeless Sd--Im galaxies become numerically dominant, while (ii) above the "bimodality" scale (V~200km/s), gas-starved E/S0s become the norm.