LoTSS Jellyfish Galaxies III. The first identification of jellyfish
  galaxies in the Perseus cluster
  In this paper we report the first identification of jellyfish galaxies in the
Perseus cluster (Abell 426). We identified four jellyfish galaxies (LEDA
2191078, MCG +07-07-070, UGC 2654, UGC 2665) within the central $2^\circ \times
2^\circ$ ($2.6\,\mathrm{Mpc} \times 2.6\,\mathrm{Mpc}$) of Perseus based on the
presence of one-sided radio continuum tails that were detected at
$144\,\mathrm{MHz}$ by the LOw Frequency ARray (LOFAR). The observed radio
tails, as well as the orientation of morphological features in the rest-frame
optical, are consistent with these four galaxies being impacted by ram pressure
stripping as they orbit through the Perseus intracluster medium. By combining
the LOFAR imaging at 144 MHz with 344 MHz imaging from the Karl G. Jansky Very
Large Array, we derived spectral indices for the disks and the stripped tails
of these jellyfish galaxies. We show that the spectral indices over the galaxy
disks are quite flat, while the indices of the stripped tails are substantially
steeper. We also identified a number of compact $\mathrm{H\alpha + [NII]}$
sources with narrowband imaging from the Isaac Newton Telescope. These sources
are brighter along the leading side of the galaxy (i.e., opposite to the
direction of the stripped tail), which is consistent with ram pressure induced
star formation. Lastly, consistent with previous works in other clusters, we
find that these jellyfish galaxies show enhanced radio luminosities for their
observed star formation rates. Given the small distance to the Perseus cluster
($D \sim 70\,\mathrm{Mpc}$, $1'' \simeq 340\,\mathrm{pc}$), these galaxies are
excellent candidates for multiwavelength follow-up observations to probe the
impact of ram pressure stripping on galaxy star formation at subkiloparsec
scales.
