GBT20A-268

Measuring the cold gas in super spiral galaxies to z < 0.3 with ARGUS

Abstract

We have discovered a class of super spiral galaxies (0.1 < z < 0.6) which lie in the same stellar mass range as giant Elliptical galaxies, and have enormous sizes and luminosities. Super spirals appear to show a significant break from the baryonic Tully-Fisher relationship (BTFR) above stellar masses > 5 x 10^11 Msun (BTFR relates the rotational velocity of a galaxy to its total gas+stellar mass). If correct, this would imply a significant deviation in the relationship between baryonic matter and dark matter at large masses, and has important implications for massive galaxy evolution. One major uncertainty is the actual amount of cold gas in super spirals: which has not be measured directly, but has been inferred from other properties. Previous attempts by our team to directly measure HI in super spirals at the GBT have largely failed because of RFI. Instead, we propose to measure gas masses through CO 1-0 emission with ARGUS in the 95-105 GHz region free of RFI. We will then be able to make realistic estimates, for the first time, of the total baryonic (stars+gas) masses for comparison with the galaxy's rotational properties.

Investigators

Name	Institution
Phil Appleton *	California Institute of Technology
Dave Frayer	Green Bank Observatory
Lauranne Lanz	Dartmouth College; California Institute of Technology; The College of New Jersey
Patrick Ogle	Space Telescope Science Institute

* indicates the PI