Tamara T. Helfer (UC Berkeley/ATNF Distinguished Visitor)

The Molecular Connection to the FIR-Radio Continuum Correlation in Galaxies - Tamara T. Helfer Colloquium

ATNF Marsfield Lecture Theatre

Abstract

The correlation between the global far-infrared (FIR) and
centimeter-wavelength radio continuum (RC) emissions in galaxies
is at the same time one of the most robust and one of the most puzzling relations in extragalactic research. Even though the RC and FIR both ultimately originate in molecular clouds, the tightness of their correlation is surprising given that the emission mechanisms for the two processes are completely different. In this talk, I discuss the relationship between the RC and CO emission for a set of galaxies selected from the BIMA Survey of Nearby Galaxies. First, I'll show that the global CO-RC correlation is as tight as the global FIR-RC correlation. Furthermore, within galaxies, the CO and RC correlation is as tight as its global value, down to the smallest linear resolution of the observations, or 100 pc. The excellent correlation between the CO, RC and FIR emission in galaxies may be a consequence of regulation by hydrostatic pressure; this model links all three emissions without invoking an explicit dependence on a star formation scenario.