Unveiling the Interplay between the GASP Jellyfish Galaxy JO194 and Its Environment with Chandra

X-ray studies of jellyfish galaxies opened a window into the physics of the interplay between the intracluster medium (ICM) and interstellar medium (ISM). In this paper, we present the study of an archival Chandra observation of the GASP jellyfish galaxy JO194. We observe X-ray emission extending from the stellar disk to the unwinding spiral arms with an average temperature of kT = 0.79 +/- 0.03 keV. To investigate the origin of the X-ray emission, we compare the observed X-ray luminosities with those expected from the star formation rates (SFRs) obtained from H alpha emission. We estimate an X-ray luminosity excess of a factor similar to 2-4 with respect to the SF; therefore, we conclude that SF is not the main event responsible for the extended X-ray emission of JO194. The metallicity in the spiral arms (Z = 0.24(-0.12)(+0.19) Z(circle dot)) is consistent with that of the ICM around JO194 (Z= 0.35 +/- 0.07); thus, we suggest that ICM radiative cooling dominates the X-ray emission of the arms. We speculate that the X-ray plasma results from the ISM-ICM interplay, although the nature of this interplay is still mostly unknown. Finally, we observe that the X-ray properties of JO194 are consistent with those of two other GASP galaxies with different stellar mass, phase-space conditions in their hosting clusters, and local ICM conditions. We suggest that the conditions required to induce extended X-ray emission in jellyfish galaxies are established at the beginning of the stripping, and they can persist on long timescales so that galaxies in different clusters and evolutionary stages can present a similar extended X-ray emission.

Automated summary

X-ray studies of jellyfish galaxies provide insights into the physics of the interaction between the interstellar medium (ISM) and intracluster medium (ICM). This study of the GASP jellyfish galaxy JO194 reveals extended X-ray emission originating from the ICM radiative cooling in the spiral arms, rather than from star formation. The observations suggest that conditions for extended X-ray emission are established at the beginning of the stripping process and can persist in galaxies in different clusters and evolutionary stages.