1 research outputs found
Walk on the Low Side: LOFAR explores the low-frequency radio emission of GASP jellyfish galaxies
Jellyfish galaxies, characterized by long filaments of stripped interstellar
medium extending from their disks, are the prime laboratories to study the
outcomes of ram pressure stripping. At radio wavelengths, they often show
unilateral emission extending beyond the stellar disk, and an excess of radio
luminosity with respect to that expected from their current star formation
rate. We present new 144 MHz images provided by the LOFAR Two-metre Sky Survey
for a sample of six galaxies from the GASP survey. These galaxies are
characterized by a high global luminosity at 144 MHz ( W
Hz), in excess compared to their ongoing star formation rate. The
comparison of radio and H images smoothed with a Gaussian beam
corresponding to 10 kpc reveals a sub-linear spatial correlation between
the two emissions with an average slope . In their stellar disk we
measure , which is close to the radio-to-star formation linear
relation. We speculate that, as a consequence of the ram pressure, in these
jellyfish galaxies the cosmic rays transport is more efficient than in normal
galaxies. Radio tails typically have higher radio-to-H ratios than the
disks, thus we suggest that the radio emission is boosted by the electrons
stripped from the disks. In all galaxies, the star formation rate has decreased
by a factor within the last yr. The observed radio emission
is consistent with the past star formation, so we propose that this recent
decline may be the cause of their radio luminosity-to-star formation rate
excess.Comment: 22 pages, 7 figures. Accepted for publication on ApJ on 24/08/202