JWST Reveals a Candidate Jellyfish Galaxy at z=1.156

TL;DR

This paper reports the discovery of a candidate jellyfish galaxy at z=1.156, showing signs of ram pressure stripping with a star-forming tail, indicating such processes occur at high redshift and may influence galaxy evolution.

Contribution

It presents the first high-redshift candidate jellyfish galaxy with a ram pressure stripped gas tail, observed with JWST and Gemini, demonstrating environmental effects at z>1.

Findings

Discovery of a jellyfish galaxy at z=1.156 with a star-forming tail.

Evidence of ram pressure stripping at high redshift.

Tail features contain very young stars (~100 Myr).

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 $0.1\text{--}1\,\mathrm{M_\odot\,yr^{-1}}$. 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.