Neutral hydrogen in galaxy clusters: impact of AGN feedback and implications for intensity mapping

VILLAESCUSA-NAVARRO FRANCISCO ; PLANELLES, SUSANA; BORGANI, STEFANO; VIEL, MATTEO; RASIA, ELENA; MURANTE, GIUSEPPE; DOLAG, KLAUS; STEINBORN, LISA; BIFFI, VERONICA; BECK, ALEXANDER; RAGONE FIGUEROA, CINTHIA

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016 vol. 456 p. 3553 - 3570

0035-8711

By means of zoom-in hydrodynamic simulations, we quantify the amount of neutral hydrogen(H I ) hosted by groups and clusters of galaxies. Our simulations, which are based on animproved formulation of smoothed particle hydrodynamics, include radiative cooling, starformation, metal enrichment and supernova feedback, and can be split into two differentgroups, depending on whether feedback from active galactic nuclei (AGN) is turned on oroff. Simulations are analysed to account for H I self-shielding and the presence of molecularhydrogen. We find that the mass in neutral hydrogen of dark matter haloes monotonicallyincreases with the halo mass and can be well described by a power law of the form M H I (M, z) ∝M 3/4 . Our results point out that AGN feedback reduces both the total halo mass and its H Imass, although it is more efficient in removing H I . We conclude that AGN feedback reducesthe neutral hydrogen mass of a given halo by ∼50 per cent, with a weak dependence on halomass and redshift. The spatial distribution of neutral hydrogen within haloes is also affectedby AGN feedback, whose effect is to decrease the fraction of H I that resides in the halo innerregions. By extrapolating our results to haloes not resolved in our simulations, we deriveastrophysical implications from the measurements of H I (z): haloes with circular velocitieslarger than ∼25 km s −1 are needed to host H I in order to reproduce observations. We find thatonly the model with AGN feedback is capable of reproducing the value of H I b H I derivedfrom available 21 cm intensity mapping observations.