TUNA Lunch Talk:

Jeff Mangum

NRAO

Densitometry and Thermometry of Starburst Galaxies

September 29

12:10PM, Room 230, NRAO, Edgemont Road

Abstract:

With a goal toward deriving the physical conditions in external galaxies, we have conducted high spatial resolution imaging of formaldehyde (H2CO) emission and absorption in a sample of starburst galaxies. We have utilized the VLA to image the volume density using the 1(10)-1(11) and 2(11)-2(12) K-doublet transitions of H2CO, while the kinetic temperature within this dense gas has been derived using ALMA measurements of several kinetic-temperature-sensitive J=3-2 and 5-4 transitions. Previous GBT measurements using H2CO and NH3 have resulted in measured volume densities in the range 10(4.5) to 10(5.5) cm(-3) and kinetic temperatures in the range from ~25 to < 250 K. In this presentation I will describe our VLA and ALMA measurements of the volume density and kinetic temperature structure in starburst galaxies and how these measurements help to inform the physical processes which drive the high kinetic temperatures in starburst environments.