5 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
On the encounter between the GASP galaxy JO36 and the radio plume of GIN 049
We report on the serendipitous discovery of an unprecedented interaction
between the radio lobe of a radio galaxy and a spiral galaxy. The discovery was
made thanks to LOFAR observations at 144 MHz of the galaxy cluster Abell 160
() provided by the LOFAR Two-metre Sky Survey. The new low-frequency
observations revealed that one of the radio plumes of the central galaxy GIN
049 overlaps with the spiral galaxy JO36. Previous studies carried out with
MUSE revealed that the warm ionized gas in the disk of JO36, traced by the
H emission, is severely truncated with respect to the stellar disk. We
further explore this unique system by including new uGMRT observations at 675
MHz to map the spectral index. The emerging scenario is that JO36 has
interacted with the radio plume in the past 200-500 Myr. The encounter resulted
in a positive feedback event for JO36 in the form of a star formation rate
burst of yr. In turn, the galaxy passage left a trace
in the radio-old plasma by re-shaping the old relativistic plasma via magnetic
draping.Comment: 20 pages, 11 figures. Accepted for publication on ApJ on September
4th, 202
On the encounter between the GASP galaxy JO36 and the radio plume of GIN 049
© 2023. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/We report on the serendipitous discovery of an unprecedented interaction between the radio lobe of a radio galaxy and a spiral galaxy. The discovery was made thanks to LOFAR observations at 144 MHz of the galaxy cluster Abell 160 () provided by the LOFAR Two-metre Sky Survey. The new low-frequency observations revealed that one of the radio plumes of the central galaxy GIN 049 overlaps with the spiral galaxy JO36. Previous studies carried out with MUSE revealed that the warm ionized gas in the disk of JO36, traced by the H emission, is severely truncated with respect to the stellar disk. We further explore this unique system by including new uGMRT observations at 675 MHz to map the spectral index. The emerging scenario is that JO36 has interacted with the radio plume in the past 200-500 Myr. The encounter resulted in a positive feedback event for JO36 in the form of a star formation rate burst of yr. In turn, the galaxy passage left a trace in the radio-old plasma by re-shaping the old relativistic plasma via magnetic draping.Peer reviewe