GASP XXXVIII: The LOFAR-MeerKAT-VLA view on the non-thermal side of a jellyfish galaxy

TL;DR

This study investigates the non-thermal radio emission of the jellyfish galaxy JW100 using multi-frequency radio observations, revealing insights into ram pressure stripping effects, magnetic fields, and AGN activity in galaxy evolution.

Contribution

It provides a detailed multi-frequency analysis of JW100, combining LOFAR, MeerKAT, and VLA data to study non-thermal emission, magnetic fields, and the interplay between star formation, stripping, and AGN activity.

Findings

Star formation in the disk was rapidly quenched by a factor of 4 within 10^7 years.

Radio emission in the tail supports the ram pressure stripping scenario.

Magnetic field strength is between 11 and 18 μG in the disk and less than 10 μG in the tail.

Abstract

Ram pressure stripping is a crucial evolutionary driver for cluster galaxies. It is thought to be able to accelerate the evolution of their star formation, trigger the activity of their central active galactic nucleus (AGN) and the interplay between the galactic and environmental gas, and eventually dissipate their gas reservoir. We explored the outcomes of ram pressure stripping by studying the non-thermal radio emission of the jellyfish galaxy JW100 in the cluster Abell 2626 ($z=0.055$) by combining LOFAR, MeerKAT, and VLA observations from 0.144 to 5.5 GHz. We studied the integrated spectra of the stellar disk, the stripped tail and the AGN, mapped the spectral index over the galaxy, and constrained the magnetic field intensity to be between 11 and 18 $\mu$G in the disk and $<10$ $\mu$G in the tail. The stellar disk radio emission is dominated by a radiatively old plasma, likely related to an older phase of high star formation rate. This suggests that the star formation was quickly quenched by a factor of 4 in a few $10^7$ yr. The radio emission in the tail is consistent with the stripping scenario, where the radio plasma originally accelerated in the disk is then displaced in the tail. The morphology of the radio and X-ray emissions supports the scenario of accretion of the magnetized environmental plasma onto the galaxy. The AGN non-thermal spectrum indicates that the relativistic electron acceleration may have occurred simultaneously with a central ionized gas outflow, thus suggesting a physical connection between the two processes.