Abstract
Jellyfish galaxies are galaxies that exhibit tentacles of debris material
suggestive of gas stripping. We have conducted the first systematic search for
jellyfish galaxies at low-z (z=0.04-0.07) in different environments. We have
visually inspected B and V-band images and identified 241+153 candidates in
41+31 galaxy clusters of the OMEGAWINGS+WINGS sample and 99 candidates in
groups and lower mass structures in the PM2GC sample. This large sample is well
suited for follow-up studies of the gas and for a detailed analysis of the
environments where such episodes of gas stripping occur. We present here the
atlas of jellyfish candidates, a first analysis of their environment and their
basic properties, such as morphologies, star formation rates and galaxy stellar
masses. Jellyfish candidates are found in all clusters and at all
clustercentric radii, and their number does not correlate with the cluster
velocity dispersion or X-ray luminosity. Interestingly, convincing cases of
jellyfish candidates are also found in groups and lower mass haloes
(10^11-10^14 M_sun). All the candidates are disky, have stellar masses
ranging from log M/M_sun < 9 to > 11.5 and the majority of them form stars, at
a rate that is on average a factor of 2 higher compared to non-stripped
galaxies of similar mass. The few post-starburst and passive candidates have
weak tentacles. We conclude that the jellyfish phenomenon is ubiquitous in
clusters and can be present even in groups and low mass haloes. Further studies
will reveal the physics of the gas stripping and clarify the mechanisms at
work.
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