Stellar mass to halo mass scaling relation for X-ray-selected low-mass galaxy clusters and groups out to redshift z ≈ 1

We present the stellar mass-halo mass scaling relation for 46 X-ray-selected low-mass clusters or groups detected in the XMM-Newton-Blanco Cosmology Survey (XMM-BCS) survey with masses 2 × 10¹³ M_⊙ ≲ M₅₀₀ ≲ 2.5 × 10¹⁴ M_⊙ (median mass 8 × 10¹³ M_⊙) at redshift 0.1 ≤ z ≤ 1.02 (median redshift 0.47). The cluster binding masses M₅₀₀ are inferred from the measured X-ray luminosities L_X, while the stellar masses M_⋆ of the galaxy populations are estimated using near-infrared (NIR) imaging from the South Pole Telescope Deep Field survey and optical imaging from the BCS survey. With the measured L_X and stellar mass M_⋆, we determine the best-fitting stellar mass-halo mass relation, accounting for selection effects, measurement uncertainties and the intrinsic scatter in the scaling relation. The resulting mass trend is M_{star }∝ M_{500}^{0.69± 0.15}, the intrinsic (lognormal) scatter is σ _{ln M_{star }|M_{500}}=0.36^{+0.07}_{-0.06}, and there is no significant redshift trend M_⋆ ∝ (1 + z)^{-0.04 ± 0.47}, although the uncertainties are still large. We also examine M_⋆ within a fixed projected radius of 0.5 Mpc, showing that it provides a cluster binding mass proxy with intrinsic scatter of ≈93 per cent (1σ in M₅₀₀). We compare our M_⋆ = M_⋆(M₅₀₀, z) scaling relation from the XMM-BCS clusters with samples of massive, Sunyaev-Zel'dovich Effect selected clusters (M₅₀₀ ≈ 6 × 10¹⁴ M_⊙) and low-mass NIR-selected clusters (M₅₀₀ ≈ 10¹⁴ M_⊙) at redshift 0.6 ≲ z ≲ 1.3. After correcting for the known mass measurement systematics in the compared samples, we find that the scaling relation is in good agreement with the high-redshift samples, suggesting that for both groups and clusters the stellar content of the galaxy populations within R₅₀₀ depends strongly on mass but only weakly on redshift out to z ≈ 1.