A GMOS/IFU Study of Jellyfish Galaxies in Massive Clusters

Abstract

Jellyfish galaxies are an intriguing snapshot of galaxies undergoing ram pressure stripping (RPS) in dense environments, showing spectacular star-forming knots in their disks and tails. We study the ionized gas properties of five jellyfish galaxies in massive clusters with Gemini GMOS/Integral Field Unit observations: MACSJ0916-JFG1 (z = 0.330), MACSJ1752-JFG2 (z = 0.353), A2744-F0083 (z = 0.303), MACSJ1258-JFG1 (z = 0.342), and MACSJ1720-JFG1 (z = 0.383). “Baldwin, Phillips, and Terlevich” diagrams show that star formation, active galactic nuclei (AGNs), or mixed effects are ionizing gas in these galaxies. Radial velocity distributions of ionized gas seem to follow disk rotation of galaxies, with the appearance of a few high-velocity components in the tails as a sign of RPS. Mean gas velocity dispersion is lower than 50 km s−1 in most star-forming regions except near AGNs or shock-heated regions, indicating that the ionized gas is dynamically cold. Integrated star formation rates (SFRs) of these galaxies range from 7 M ⊙ yr−1 to 35 M ⊙ yr−1, and the tail SFRs are from 0.6 M ⊙ yr−1 to 16 M ⊙ yr−1, which are much higher than those of other jellyfish galaxies in the local universe. These high SFR values imply that RPS triggers intense star formation activity in these extreme jellyfish galaxies. The phase-space diagrams demonstrate that the jellyfish galaxies with higher stellar masses and higher host cluster velocity dispersion are likely to have more enhanced star formation activity. The jellyfish galaxies in this study have similar gas kinematics and dynamical states to those in the local universe, but they show a much higher SFR.

LoTSS Jellyfish Galaxies. IV. Enhanced Star Formation on the Leading Half of Cluster Galaxies and Gas Compression in IC3949

“…The two galaxies in Figure 6 with sSFR peaks that are on the TH and significantly offset from the galaxy center are GMP2599 (MaNGA plate-ifu: 9862-9101) and MRK0881 (MaNGA plate-ifu: 8604-9102). These sSFR peaks may be indicative of ongoing star formation along the stripped tail for these galaxies, as has been seen previously for some jellyfish galaxies (e.g., Gavazzi et al 2001;Yagi et al 2010;Poggianti et al 2017;Boselli et al 2018;Lee et al 2022b;Hess et al 2022). The MaNGA field of view (FOV) is too small to directly probe these stripped tails; however, for both galaxies the Hα emission fills the MaNGA FOV toward the direction of the observed radio tail, suggesting that there may be extraplanar star formation along the tail beyond the MaNGA coverage.…”