paper

HII and H2 in the envelopes of cooling flow central galaxies

arXiv:astro-ph/0504413 · doi:10.1111/j.1365-2966.2005.09073.x

Abstract

We report observations of ionized and warm molecular gas in the extended regions of the central galaxies in several cooling flow clusters. These show that both gas phases are present in these clusters to large radii. We trace both Pa alpha and H2 lines to radii in excess of 20 kpc. The surface brightness profiles of the two phases trace each other closely. Apart from very close to the central AGN, line ratios in and between the phases vary only slowly with position. The kinematics of the phases are indistinguishable and away from the influence of the central AGN both the mean and dispersion in velocity are low (<= 100 km/s) ruling out kinematic support of the molecular gas. All of the above indicates that the mechanisms for heating the molecular gas and ionizing the HII regions are highly coupled. The highest surface brightness emission within a few kpc of the central AGN is distinct, both kinematically and thermally from that at larger radii. The relative strengths of the Pa alpha to the H2 lines indicates a source of UV excitation rich in EUV relative to FUV photons, e.g. a black body with a temperature >= 10^5 K.

accepted by MNRAS 4 april 2005

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