Speaker
Marissa Rosenberg
(Leiden Observatory)
Description
(Ultra) Luminous Infrared Galaxies ((U)LIRGs) are galaxies exhibiting an extremely high infrared luminosity and may be the evolutionary transition phase between starburst galaxies and QSOs. Understanding the heating and cooling mechanisms in these galaxies give us insight to the driving mechanisms that fuel this transition. Molecular emission lines play a crucial role in the cooling of excited gas, and recently with Herschel we are able to observe carbon monoxide (CO), one of the most abundant and brightest molecules. By studying the CO excitation ladder and comparing the CO intensities to models, we can determine whether the gas is excited by UV radiation, Xrays, cosmic rays, or mechanical heating. However the models suffer from degeneracies. In order to understand the degeneracies, we perform a chi-squared minimized fit of the CO ladder of well studied starburst galaxies. Then by adding ancillary data (13CO, HCO+, and HCN), we are able to constrain these degeneracies.
Author
Marissa Rosenberg
(Leiden Observatory)