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arXiv · 1407.5627

Surface photometry of BCGs and intracluster stars in Lambda-CDM

Andrew P. Cooper·Liang Gao·Qi Guo·Carlos S. Frenk·Adrian Jenkins·Volker Springel·Simon D. M. White
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Abstract

We simulate the phase-space distribution of stellar mass in 9 massive Lambda-CDM galaxy clusters by applying the semi-analytic particle tagging method of Cooper et al. to the Phoenix suite of high-resolution N-body simulations (M200 = 7.5 to 33 x 10^14 Msol). The resulting surface brightness (SB) profiles of brightest cluster galaxies (BCGs) match well to observations. On average, stars formed in galaxies accreted by the BCG account for ~90 per cent of its total mass (the remainder is formed in situ). In circular BCG-centred apertures, the superposition of multiple debris clouds (each ~10 per cent of the total BCG mass) from different progenitors can result in an extensive outer diffuse component, qualitatively similar to a 'cD envelope'. These clouds typically originate from tidal stripping at z < 1 and comprise both streams and the extended envelopes of other massive galaxies in the cluster. Stars at very low SB contribute a significant fraction of the total cluster stellar mass budget: in the central 1 Mpc^2 of a z ~ 0.15 cluster imaged at SDSS-like resolution, our fiducial model predicts 80-95 per cent of stellar mass below a SB of mu_V = 26.5 mag arcsec^2 is associated with accreted stars in the envelope of the BCG. The ratio of BCG stellar mass (including this diffuse component) to total cluster stellar mass is ~30 per cent.

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Andrew P. Cooper, Liang Gao, Qi Guo, Carlos S. Frenk, Adrian Jenkins, Volker Springel, Simon D. M. White. 2015-07-05. Surface photometry of BCGs and intracluster stars in Lambda-CDM. https://arxiv.org/abs/1407.5627

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