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Setting firmer constraints on the evolution of the most massive, central galaxies from their local abundances and ages

Setting firmer constraints on the evolution of the most massive, central galaxies from their local abundances and ages
Setting firmer constraints on the evolution of the most massive, central galaxies from their local abundances and ages
There is still much debate surrounding how the most massive, central galaxies in the local universe have assembled their stellar mass, especially the relative roles of in situ growth versus later accretion via mergers. In this paper, we set firmer constraints on the evolutionary pathways of the most massive central galaxies by making use of empirical estimates on their abundances and stellar ages. The most recent abundance matching and direct measurements strongly favour that a substantial fraction of massive galaxies with Mstar>3 × 1011?M? reside at the centre of clusters with mass Mhalo>3 × 1013?M?. Spectral analysis supports ages >10 Gyr, corresponding to a formation redshift zform>2. We combine these two pieces of observationally based evidence with the mass accretion history of their host dark matter haloes. We find that in these massive haloes, the stellar mass locked up in the central galaxy is comparable to, if not greater than, the total baryonic mass at zform. These findings indicate that either only a relatively minor fraction of their present-day stellar mass was formed in situ at zform, or that these massive, central galaxies form in the extreme scenario where almost all of the baryons in the progenitor halo are converted into stars. Interestingly, the latter scenario would not allow for any substantial size growth since the galaxy's formation epoch either via mergers or expansion. We show our results hold irrespective of systematic uncertainties in stellar mass, abundances, galaxy merger rates, stellar initial mass function, star formation rate and dark matter accretion histories.
0035-8711
2001-2010
Buchan, Stewart
8c3f2c85-3ffa-491c-91b5-b7bbeb0021cd
Shankar, Francesco
b10c91e4-85cd-4394-a18a-d4f049fd9cdb
Buchan, Stewart
8c3f2c85-3ffa-491c-91b5-b7bbeb0021cd
Shankar, Francesco
b10c91e4-85cd-4394-a18a-d4f049fd9cdb

Buchan, Stewart and Shankar, Francesco (2016) Setting firmer constraints on the evolution of the most massive, central galaxies from their local abundances and ages. Monthly Notices of the Royal Astronomical Society, 462 (2), 2001-2010. (doi:10.1093/mnras/stw1771).

Record type: Article

Abstract

There is still much debate surrounding how the most massive, central galaxies in the local universe have assembled their stellar mass, especially the relative roles of in situ growth versus later accretion via mergers. In this paper, we set firmer constraints on the evolutionary pathways of the most massive central galaxies by making use of empirical estimates on their abundances and stellar ages. The most recent abundance matching and direct measurements strongly favour that a substantial fraction of massive galaxies with Mstar>3 × 1011?M? reside at the centre of clusters with mass Mhalo>3 × 1013?M?. Spectral analysis supports ages >10 Gyr, corresponding to a formation redshift zform>2. We combine these two pieces of observationally based evidence with the mass accretion history of their host dark matter haloes. We find that in these massive haloes, the stellar mass locked up in the central galaxy is comparable to, if not greater than, the total baryonic mass at zform. These findings indicate that either only a relatively minor fraction of their present-day stellar mass was formed in situ at zform, or that these massive, central galaxies form in the extreme scenario where almost all of the baryons in the progenitor halo are converted into stars. Interestingly, the latter scenario would not allow for any substantial size growth since the galaxy's formation epoch either via mergers or expansion. We show our results hold irrespective of systematic uncertainties in stellar mass, abundances, galaxy merger rates, stellar initial mass function, star formation rate and dark matter accretion histories.

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Accepted/In Press date: 19 July 2016
e-pub ahead of print date: 28 July 2016
Published date: 21 October 2016
Organisations: Astronomy Group

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Local EPrints ID: 400178
URI: http://eprints.soton.ac.uk/id/eprint/400178
ISSN: 0035-8711
PURE UUID: b7efed0d-9772-41ef-aee8-189ffcbfdb4a

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Date deposited: 12 Sep 2016 14:30
Last modified: 16 Dec 2019 19:44

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