GASP XXXIV: Unfolding the thermal side of ram pressure stripping in the jellyfish galaxy JO201

TL;DR

This study investigates the X-ray and optical properties of the jellyfish galaxy JO201, revealing that its extended X-ray emission originates from hot plasma on the ISM surface due to ICM-ISM interactions, influencing star formation and optical emissions.

Contribution

It provides a detailed analysis of the thermal X-ray emission in JO201, linking it to ICM-ISM interactions and demonstrating its impact on galaxy evolution and optical line emissions.

Findings

X-ray emission is from hot plasma on the ISM surface.

X-ray emission closely follows the ISM distribution.

Warm plasma influences optical line ratios, indicating ICM-ISM interplay.

Abstract

X-ray studies of jellyfish galaxies play a crucial role in understanding the interactions between the interstellar medium (ISM) and the intracluster medium (ICM). In this paper, we focused on the jellyfish galaxy JO201. By combining archival Chandra observations, MUSE H$\alpha$ cubes, and maps of the emission fraction of the diffuse ionised gas, we investigated both its high energy spectral properties and the spatial correlation between its X-ray and optical emissions. The X-ray emission of JO201 is provided by both the Compton thick AGN (L$_{\text{X}}^{0.5-10 \text{keV}}$=2.7$\cdot$10$^{41}$ erg s$^{-1}$, not corrected for intrinsic absorption) and an extended component (L$_{\text{X}}^{0.5-10 \, \text{keV}}\approx$1.9-4.5$\cdot$10$^{41}$ erg s$^{-1}$) produced by a warm plasma (kT$\approx$1 keV), whose luminosity is higher than expected from the observed star formation (L$_{\text{X}}\sim$3.8$\cdot10^{40}$ erg s$^{-1}$). The spectral analysis showed that the X-ray emission is consistent with the thermal cooling of hot plasma. These properties are similar to the ones found in other jellyfish galaxies showing extended X-ray emission. A point-to-point analysis revealed that this X-ray emission closely follows the ISM distribution, whereas CLOUDY simulations proved that the ionisation triggered by this warm plasma would be able to reproduce the [OI]/H$\alpha$ excess observed in JO201. We conclude that the galactic X-ray emitting plasma is originated on the surface of the ISM as a result of the ICM-ISM interplay. This process would entail the cooling and accretion of the ICM onto the galaxy, which could additionally fuel the star formation, and the emergence of [OI]/H$\alpha$ excess in the optical spectrum.