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 degrees x2 degrees (2.6  Mpc x 2.6  Mpc) of Perseus based on the presence of one-sided radio continuum tails that were detected at 144  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 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  similar to  70  Mpc, 1 '' similar or equal to  340  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.

Automated summary

In this paper, the first identification of jellyfish galaxies in the Perseus cluster is reported. Four jellyfish galaxies within the central region of Perseus were identified based on their one-sided radio continuum tails detected by LOFAR. The observed radio tails and the orientation of morphological features suggest that these galaxies have been impacted by ram pressure stripping in the intracluster medium. Spectral indices derived from multi-frequency imaging show different properties for the disk and stripped tail regions of these galaxies. Additionally, the presence of compact H alpha + [NII] sources along the leading side of the galaxies indicates ram pressure induced star formation. These jellyfish galaxies also exhibit enhanced radio luminosities compared to their star formation rates. The close proximity of the Perseus cluster makes these galaxies excellent candidates for further multiwavelength observations to study the impact of ram pressure stripping on galaxy star formation at subkiloparsec scales.