JWST Reveals a Candidate Jellyfish Galaxy at z=1.156

Abstract

We report the discovery of COSMOS2020-635829 as a candidate jellyfish galaxy undergoing ram pressure stripping in a (proto)cluster at $z>1$. High-resolution imaging from the James Webb Space Telescope reveals a symmetric stellar disk coupled to a unilateral tail of star-forming knots to the south. Using Gemini GMOS IFU observations, we show that these extra-planar continuum sources are embedded within an ionized gas tail that is kinematically connected to the disk of COSMOS2020-635829. If confirmed, this represents the highest-redshift discovery of a ram pressure stripped ionized gas tail. The tail sources are characterized by extremely young stellar populations ($\lesssim 100\mathrm{Myr}$), have stellar masses of $\sim 10^8{\mathrm{M}}_{\odot }$, and star formation rates of $0.1\text{–}1{\mathrm{M}}_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$. This work shows that ram pressure stripping can potentially perturb group and cluster galaxies at $z>1$ and may contribute to environmental quenching even near Cosmic Noon.

14 pages, 10 figures, 1 appendix, accepted to ApJ