A 10¹⁰SOLAR MASS FLOW OF MOLECULAR GAS IN THE A1835 BRIGHTEST CLUSTER GALAXY

Abstract

We report ALMA Early Science observations of the Abell 1835 brightest cluster\ngalaxy (BCG) in the CO (3-2) and CO (1-0) emission lines. We detect 5E10 solar\nmasses of molecular gas within 10 kpc of the BCG. Its velocity width of ~130\nkm/s FWHM is too narrow to be supported by dynamical pressure. The gas may\ninstead be supported in a rotating, turbulent disk oriented nearly face-on. The\ndisk is forming stars at a rate of 100-180 solar masses per year. Roughly 1E10\nsolar masses of molecular gas is projected 3-10 kpc to the north-west and to\nthe east of the nucleus with line of sight velocities lying between -250 km/s\nto +480 km/s with respect to the systemic velocity. Although inflow cannot be\nruled out, the rising velocity gradient with radius is consistent with a broad,\nbipolar outflow driven by radio jets or buoyantly rising X-ray cavities. The\nmolecular outflow may be associated with an outflow of hot gas in Abell 1835\nseen on larger scales. Molecular gas is flowing out of the BCG at a rate of\napproximately 200 solar masses per year, which is comparable to its star\nformation rate. How radio bubbles lift dense molecular gas in their updrafts,\nhow much gas will be lost to the BCG, and how much will return to fuel future\nstar formation and AGN activity are poorly understood. Our results imply that\nradio-mechanical (radio mode) feedback not only heats hot atmospheres\nsurrounding elliptical galaxies and BCGs, it is able to sweep higher density\nmolecular gas away from their centers.\n