The Outer Stellar Mass of Massive Galaxies: A Simple Tracer of Halo Mass with Scatter Comparable to Richness and Reduced Projection Effects

Abstract

Using the weak gravitational lensing data from the Hyper Suprime-Cam Subaru Strategic Program (HSC survey), we study the potential of different stellar mass estimates in tracing halo mass. We consider galaxies with log 10 (M /M )> 11.5 at 0.2 < z < 0.5 with carefully measured light profiles, and clusters from the redMaP-Per and CAMIRA richness-based algorithms. We devise a method (the "Top-N test") to evaluate the scatter in the halo mass-observable relation for different tracers, and to inter-compare halo mass proxies in four number density bins using stacked galaxygalaxy lensing profiles. This test reveals three key findings. Stellar masses based on CModel photometry and aperture luminosity within R <30 kpc are poor proxies of halo mass. In contrast, the stellar mass of the outer envelope is an excellent halo mass proxy. The stellar mass within R = [50, 100] kpc, M ,[50,100] , has performance comparable to the state-of-the-art richness-based cluster finders at log 10 M vir 14.0 and could be a better halo mass tracer at lower halo masses. Finally, using N-body simulations, we find that the lensing profiles of massive halos selected by M , [50,100] are consistent with the expectation for a sample without projection or mis-centering effects. Richness-selected clusters, on the other hand, display an excess at R ∼ 1 Mpc in their lensing profiles, which may suggest a more significant impact from selection biases. These results suggest that M -based tracers have distinct advantages in identifying massive halos, which could open up new avenues for cluster cosmology. The codes and data used in this work can be found here:

Inferring halo masses with Graph Neural Networks

“…There has been an extensive program of weighing the masses of halos and clusters, using a wealth of techniques including gravitational lensing (Mandelbaum 2015;Huang et al 2020Huang et al , 2021, rotation curves of galaxies (Sofue & Rubin 2001;Sofue 2015), abundance matching (Behroozi et al 2010), Sunyaev-Zeldovich effect (Grego et al 2001), X-rays observations (Landry et al 2013), velocity dispersion (Saro et al 2013) and kinematics of satellite galaxies (Wojtak & Mamon 2013;Seo et al 2020) among others; see, e.g. Old et al (2015) for a comparison of different techniques for galaxy clusters.…”

Reaching for the Edge I: Probing the Outskirts of Massive Galaxies with HSC, DECaLS, SDSS, and Dragonfly

“…Third, stellar halos show clear dependence on both stellar mass and halo mass, and can therefore provide insight about the galaxy-halo connection (e.g. Krick & Bernstein 2007;Huang et al 2020;Huang et al 2021). Finally, stellar halos are expected to show strong redshift evolution which can be used as a strong constraint on galaxy evolution models (e.g.…”

The Sphere of Influence of the Bright Central Galaxies in the Diffuse Light of SDSS Clusters

“…Detailed kinematic analysis of the hydrodynamical simulations of cluster formation could be tremendously helpful for providing insight to the growth of the BCG sphere of influence, as well as an indirect check of the physical link between 𝑟 𝑠 and 𝑅 SOI . Observationally, our work can be easily extended to the larger cluster catalogues (Zou et al 2021;Wen & Han 2021;Yang et al 2021) and deeper photometry (Huang et al 2021;Li et al 2021) from current stage-III imaging surveys. Future ground-based and space missions like the LSST, Euclid, Roman, and CSST with even larger cluster samples, deeper photometry, and sharper shear measurements will greatly enhance our capability of seeing cluster formation through the diffuse light.…”

“…By examining the stacked surface stellar mass density profiles of clusters at fixed 𝑀 BCG * but different 𝜆 (as will be demonstrated later in §5), we find that the effective aperture of our 𝑀 BCG * estimates is 𝑅 * 50 kpc. Therefore, our fiducial 𝑀 BCG * roughly corresponds to 𝑀 * ,50kpc in the language of Huang et al (2021). To test the robustness of our 𝑅 SOI detection, we also measure for each BCG an aperture-based stellar mass 𝑀 * ,20kpc , i.e., stellar mass enclosed within a fixed aperture of 20 kpc.…”