Lawrence Cram
U. Sydney

Star formation and 1.4 GHz radio emission
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Star formation produces radio emission, at low frequencies (1.4 GHz) via
cosmic ray acceleration in supernova events. Radio observations hold the
promise of revealing star formation rates and processes unhindered by the
obscuration that is prevalent in optical observations, but have as yet been
little exploited.

We have been developing the application of 1.4 GHz observations to star
formation studies in two directions:

(1) The Phoenix Deep Survey, a 1.4 GHz radiofrequency survey of a 2 degree
field made with the Australia Telescope Compact Array, is designed to
explore star formation rates in individual galaxies to z ~ 0.5. Our work to
date has characterised the sub-mJy radio source population, explored
optical counterparts photometrically and spectroscopically, and
demonstrated a remarkably close parallel between radio and H-alpha
properties in this population.

(2) Data mining for a multiplicity of star-formation diagnostics in field
galaxies has allowed us to correlate star-formation diagnostics for several
hundred galaxies. This work has reinforced the promise of 1.4 GHz methods,
and revealed some interesting apparent inconsistencies between often-used
diagnostics.

In addition to outlining the methods and results of our observing programs,
the talk will also describe recent theoretical work that suggests ways to
explore the sporadic or bursty character of star formation.