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

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, Multi Unit Spectroscopic Explorer Hα cubes, and maps of the emission fraction of the diffuse ionized 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 active galactic nucleus (L ${}_{{\rm{X}}}^{0.5-10\mathrm{keV}}$ = 2.7 · 10<SUP>41</SUP> erg s<SUP>-1</SUP>, not corrected for intrinsic absorption) and an extended component (L ${}_{{\rm{X}}}^{0.5\mbox{--}10\,\mathrm{keV}}\,\approx $ 1.9-4.5 · 10<SUP>41</SUP> erg s<SUP>-1</SUP>) produced by a warm plasma (kT $\approx 1$ keV), whose luminosity is higher than expected from the observed star formation (L ${}_{{\rm{X}}}\,\sim $ 3.8 · 10<SUP>40</SUP>erg s<SUP>-1</SUP>). 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 ionization triggered by this warm plasma would be able to reproduce the [O I]/Hα excess observed in JO201. We conclude that the galactic X-ray emitting plasma originates 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 [O I]/Hα excess in the optical spectrum.