Giant disk galaxies : Where environment trumps mass in galaxy evolution

Understand

We identify some of the most HI massive and fastest rotating disk galaxies in the local universe with the aim of probing the processes that drive the formation of these extreme disk galaxies.

• By combining data from the Cosmic Flows project, which has consistently reanalyzed archival galaxy HI profiles, and 3.6$\mu$m photometry obtained with the Spitzer Space Telescope, with which we can measure stellar mass, we use the baryonic Tully-Fisher (BTF) relationship to explore whether these massive galaxies are distinct.
• We discuss several results, but the most striking is the systematic offset of the HI-massive sample above the BTF.
• These galaxies have both more gas and more stars in their disks than the typical disk galaxy of similar rotational velocity.