Abstract
The thermal and chemical properties of the hot diffuse intragroup medium
(IGrM) provide important constraints on the feedback processes
associated with massive galaxy formation and evolution. Here we explore
these constraints via a detailed analysis of the global properties of
simulated z <3 galaxy groups drawn from a cosmological simulation
that includes a well-constrained prescription for momentum-driven,
stellar/supernova-powered galactic outflows but no active galactic
nucleus (AGN) feedback. Our simulation successfully reproduces the key
observed IGrM properties, including X-ray trends, for all but the most
massive groups. The z <1 redshift evolution of these is also
consistent with the observations. Contrary to expectations, the
simulated groups' IGrM does not suffer catastrophic cooling. Yet, the z
= 0 group stellar mass is ˜2× too large. We show that this
is due to the build-up of cold gas in the massive galaxies before they
are incorporated inside groups. This indicates that other feedback
mechanisms must activate in real galaxies once they grow to
M* ≈ a few ×1010 M⊙ and
that these must be powerful enough to expel a significant fraction of
the gas from the galactic haloes. Gentle `maintenance-mode' AGN feedback
would be insufficient to bring the stellar and baryonic fractions into
agreement with the observations. Just as importantly, we find that the
stellar/supernova-powered winds are essential for understanding the IGrM
metal abundances. Our simulation is able to reproduce the observed
relationship between the global IGrM iron and silicon abundances and the
group X-ray temperature, and these results should be relatively
insensitive to the addition of AGN feedback.
Original language | English |
---|---|
Pages (from-to) | 4266-4290 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 456 |
Issue number | 4 |
DOIs | |
Publication status | Published - 13 Jan 2016 |
Keywords
- methods: numerical
- galaxies: formation
- galaxies: groups: general
- galaxies: star formation
- galaxies: stellar content
- X-rays: galaxies: clusters