MACS1931 BCG MIRI MRS data

In this work, we perform a combined study of the warm (100-1000 K) and cold (10-100 K) phases of molecular gas in the brightest cluster galaxy (BCG) of a cool-core galaxy cluster, MACS1931-26 at z~0.35. This galaxy has a massive H2 reservoir, high star formation, and a radio-loud active galactic nucleus (AGN). We present new JWST observations of this system revealing warm H2 co-spatial with the cold gas traced by CO, distributed in a tail-like structure extended over 30 kpc around the BCG, reaching out to the circumgalactic medium of this galaxy. Analysis of the H2 pure rotational lines H2S(1), H2S(5), and H2S(9) show an excitation temperature of ~510 K for the BCG and ~541 K for the tail. We trace cold gas towards MACS1931-26 BCG using the archival CO(3-2) emission line observed with the ALMA interferometry array and calculate the warm-to-cold gas mass ratio. The warm-to-cold molecular gas fraction is comparable in the BCG (~1.0 %) and the tail (~1.3 %). Our analysis suggests that shocks and X-rays can both contribute to the heating of the H2-emitting gas, and the dissipation of the kinetic energy of the H2 emitting gas is sufficient to lead to the formation of the CO-emitting gas. This observation provides new insights into the molecular gas distribution and its potential role in the interplay between the central galaxy and its circumgalactic environment.