Hyper Suprime-Cam view of the CMASS galaxy sample

Halo mass as a function of stellar mass, size, and Sérsic index

¹ Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
e-mail: sonnenfeld@strw.leidenuniv.nl
² Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan
³ Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544, USA

Received: 17 September 2018
Accepted: 9 November 2018

Abstract

Aims. We wish to determine the distribution of dark matter halo masses as a function of the stellar mass and the stellar mass profile for massive galaxies in the Baryon Oscillation Spectroscopic Survey (BOSS) constant-mass (CMASS) sample.

Methods. We used grizy photometry from the Hyper Suprime-Cam (HSC) to obtain Sérsic fits and stellar masses of CMASS galaxies for which HSC weak-lensing data are available. This sample was visually selected to have spheroidal morphology. We applied a cut in stellar mass, log M_*/M_⊙ >  11.0, and selected ∼10 000 objects thus. Using a Bayesian hierarchical inference method, we first investigated the distribution of Sérsic index and size as a function of stellar mass. Then, making use of shear measurements from HSC, we measured the distribution of halo mass as a function of stellar mass, size, and Sérsic index.

Results. Our data reveal a steep stellar mass-size relation R_e ∝ M_*^βR, with β_R larger than unity, and a positive correlation between Sérsic index and stellar mass: n ∝ M_*^0.46. The halo mass scales approximately with the 1.7 power of the stellar mass. We do not find evidence for an additional dependence of halo mass on size or Sérsic index at fixed stellar mass.

Conclusions. Our results disfavour galaxy evolution models that predict significant differences in the size growth efficiency of galaxies living in low- and high-mass halos.