Speaker
Jennifer Schober
(Nordita)
Description
Magnetic fields are omnipresent in local galaxies and can affect the star formation
process crucially. Observational evidence between the coupling of the magnetic field
and the star formation rate (SFR) comes from the far-infrared(FIR)-radio correlation
which holds over more than six orders of magnitude. While the FIR radiation is a
tracer of the SFR, radio emission is typically synchrotron radiation and thus depends
on the magnetic energy density. The latter can be assumed to be in equipartition with
the turbulent energy density as a result of efficient small-scale dynamo
amplification. With a steady-state model for cosmic ray electrons we determine the
galactic synchrotron flux as a function of redshift z. Our model reproduces the
observed FIR-radio correlation well at z=0. With increasing redshift we predict a
decrease of the synchrotron flux. This leads to a deviation from the FIR-radio
correlation from its present-day appearance which could already be detected at z
\approx 2 if the gas density increases strongly with z. Our model can be tested in
the near future with ultra-deep radio surveys.
Primary author
Jennifer Schober
(Nordita)
