Radio continuum emission from local analogs of high-z faint LAEs:
  Blueberry galaxies
  We present a radio continuum study of a population of extremely young and
starburst galaxies, termed as blueberries at ${\sim}$ 1 GHz using the upgraded
Giant Metrewave Radio Telescope (uGMRT). We find that their radio-based star
formation rate (SFR) is suppressed by a factor of ${\sim}$ 3.4 compared to the
SFR based on optical emission lines. This might be due to (i) the young ages of
these galaxies as a result of which a stable equilibrium via feedback from
supernovae has not yet been established (ii) escape of cosmic ray electrons via
diffusion or galactic scale outflows. The estimated non-thermal fraction in
these galaxies has a median value of ${\sim}$0.49, which is relatively lower
than that in normal star-forming galaxies at such low frequencies. Their
inferred equipartition magnetic field has a median value of 27 ${\mu}$G, which
is higher than those in more evolved systems like spiral galaxies. Such high
magnetic fields suggest that small-scale dynamo rather than large-scale dynamo
mechanisms might be playing a major role in amplifying magnetic fields in these
galaxies.
