Size-mass relation of the brightest cluster galaxies at z 1
Abstract
We present the size-mass relation of the brightest cluster galaxies (BCGs) at 0.1 < z < 1.4 using the imaging data obtained by the Hyper Suprime-Cam Subaru Strategic Program. Our sample consists of 471 photometrically selected BCGs with stellar mass logM*/M⊙ = 11-12. We measure the size of the BCGs using i-band imaging and model fits based on a single Sérsic light profile. Stellar masses are determined through spectral energy distribution fitting using Sérsic-modelled photometry data across five optical bands (grizy). The size-mass scaling relation of BCGs is $r_\mathrm{ e}\propto M_*^{0.73-1.00}$ at z < 1, with a slope that does not evolve significantly. The slope of the size-mass relation for BCGs is steeper than other non-BCG galaxies, which implies that BCGs are a special galaxy population. The size of BCGs at a given stellar mass evolves rapidly as ∝ (1 + z)-1.58 ± 0.13 and increases with redshift by a factor of 2.5 from z ~ 1.2 to z ~ 0.2. The rapid size growth is in agreement with semi-analytical model results, indicating that the BCG growth is dominated by frequent minor mergers. Furthermore, we explore the size-mass relationship of BCGs with respect to the halo mass of the cluster and find there is no significant correlation, which might imply that a dependence on the environment predominantly affects the outer envelope of the BCGs.
- Publication:
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Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2024
- DOI:
- 10.1093/mnras/stae1374
- Bibcode:
- 2024MNRAS.531.4006Y