Satellite kinematics - II. The halo mass-luminosity relation of central galaxies in SDSS

Abstract

The kinematics of satellite galaxies reflect the masses of the extended dark matter haloes in which they orbit, and thus shed light on the mass–luminosity relation (MLR) of their corresponding central galaxies. In this paper, we select a large sample of centrals and satellites from the Sloan Digital Sky Survey and measure the kinematics (velocity dispersions) of the satellite galaxies as a function of the r‐band luminosity of the central galaxies. Using the analytical framework presented in More, van den Bosch & Cacciato, we use these data to infer both the mean and the scatter of the MLR of central galaxies, carefully taking account of selection effects and biases introduced by the stacking procedure. As expected, brighter centrals on average reside in more massive haloes. In addition, we find that the scatter in halo masses for centrals of a given luminosity, σlog M, also increases with increasing luminosity. As we demonstrate, this is consistent with σlog L, which reflects the scatter in the conditional probability function P(Lc|M), being independent of halo mass. Our analysis of the satellite kinematics yields σlog L= 0.16 ± 0.04, in excellent agreement with constraints from clustering and group catalogues, and with predictions from a semi‐analytical model of galaxy formation. We thus conclude that the amount of stochasticity in galaxy formation, which is characterized by σlog L, is well constrained, independent of halo mass and in a good agreement with current models of galaxy formation.

Galaxies in X-Ray Groups. Ii. A Weak Lensing Study of Halo Centering

“…The most common failure mode was the selection of satellites as MMGG scale because they had higher stellar masses than the true centrals, which happened in 12% of cases. The frequency of this occurrence depends on the way we populate halos with mock galaxies following the stellar-mass-halo-mass relation of Leauthaud et al (2012), but we note that scatter in this relation is consistent with that found in other analyses (Yang et al 2009;More et al 2009;Reddick et al 2012). The remaining centering failures were evenly split between cases where X-ray errors misplaced the search region and photometric redshift errors scattered centrals out of their groups.…”

“…Groups and clusters form from mergers of halos where the most massive halo becomes the host halo with its central galaxy, and smaller halos become subhalos with satellite galaxies. Several analyses of data from group catalogs and field surveys have found that there is some intrinsic scatter in stellar mass and luminosity at fixed halo mass (Yang et al 2009;More et al 2009;Leauthaud et al 2012;Reddick et al 2012), which implies that halos can end up with satellites that are intrinsically more massive or luminous than the central galaxy. Additionally, there are uncertainties in measuring any observable quantity such as stellar mass that can cause a satellite to be misidentified as the most massive central galaxy, and structure projected along the line of sight can confuse the identification of member galaxies.…”

Tracing Galaxies Through Cosmic Time With Number Density Selection

“…However, an additional source of scatter is introduced when the stellar mass-halo mass relationship is applied. This scatter is on the order of 0.16-0.2 dex at z = 0, with the scatter presumably increasing with redshift (More et al 2009;Reddick et al 2012). A comparable analysis to that presented in this paper would be needed.…”

The dark matter haloes of moderate luminosity X-ray AGN as determined from weak gravitational lensing and host stellar masses

“…From a global perspective that includes all galaxies, tremendous progress has had been made in recent years in terms of understanding and modelling the connection between galaxy stellar mass and dark matter halo mass out to z = 1 and beyond (Mandelbaum et al 2006;More et al 2009;Behroozi, Conroy & Wechsler 2010;Moster et al 2010;Leauthaud et al 2011Leauthaud et al , 2012a. At the core of these models is the stellar-to-halo mass relation (SHMR) for central galaxies.…”

“…In addition to the SHMR, these methods also constrain how satellite galaxies populate dark matter haloes as a function of galaxy mass. Finally, the SHMR may also be constrained as a function of other properties beyond stellar mass, such as galaxy colour or star formation activity (Mandelbaum et al 2006;More et al 2009;Hearin et al 2014;Tinker et al 2013).…”