GASP XXIII: A Jelly fi sh Galaxy as an Astrophysical Laboratory of the Baryonic Cycle

Abstract

With MUSE, Chandra , VLA, ALMA, and UVIT data from the GAS P program, we study the multiphase baryonic components in a jelly fi sh galaxy ( JW100 ) with a stellar mass 3.2

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10 11 M e hosting an active galactic nucleus ( AGN ) . We present its spectacular extraplanar tails of i onized and molecular gas, UV stellar light, and X-ray and radio continuum emission. This galaxy repres ents an excellent laborato ry to study the interplay between different gas phases a nd star formation and the in fl uence of gas stripping, gas heating, and AGNs. We analyze the physical origin of the emission at differe nt wavelengths in the tail, in particular in situ star formation ( related to H α ,CO,andUVemission ) , synchrotron emission fr om relativistic electrons ( producing the radio continuum ) , and heating of the stripp ed interstellar medium ( ISM; responsible for the X-ray emission ) . We show the similarities and differences of the spa tial distributions of ionized gas, molecular gas, and UV light and argue that the mismatch on small scales ( 1kpc ) is due to different stages of the star formation process. We present the relation H α – X-ray surface brightness, which is steeper for star-forming regions than for diffuse ionized gas regions with a high [ O I ] / H α ratio. We propose that ISM he ating due to interaction with the intracluster medium ( either for mixing, thermal conduction, or shocks ) is responsible for the X-ray tail, observed [ O I ] excess, and lack of star formation in the northe rn part of the tail. We also report the tentative discovery in the tail of the most distant ( and among the brightest ) currently known ULX, a pointlike ultraluminous X-ray source commonly originating in a binary stellar syste m powered by either an intermediate- mass black hole or a magnetized neutron star.