Galaxy halo masses and satellite fractions from galaxy-galaxy lensing in the Sloan Digital Sky Survey: stellar mass, luminosity, morphology and environment dependencies

Abstract

The relationship between galaxies and dark matter (DM) can be characterized by the halo mass of the central galaxy and the fraction of galaxies that are satellites. Here, we present observational constraints from the Sloan Digital Sky Survey on these quantities as a function of r-band luminosity and stellar mass using galaxy-galaxy weak lensing, with a total of 351 507 lenses. We use stellar masses derived from spectroscopy and virial halo masses derived from weak gravitational lensing to determine the efficiency with which baryons in the halo of the central galaxy have been converted into stars. We find that an L * galaxy with a stellar mass of 6 × 10 10 M is hosted by a halo with mass of 1.4 × 10 12 h −1 M , independent of morphology, yielding baryon conversion efficiencies of 17 +10 −5 per cent (early-types) and 16 +15 −6 per cent (latetypes) at the 95 per cent confidence level (statistical, not including systematic uncertainty due to assumption of a universal initial mass function). We find that for a given stellar mass, the halo mass is independent of morphology below M stellar = 10 11 M , in contrast to typically a factor of 2 difference in halo mass between ellipticals and spirals at a fixed luminosity. This suggests that stellar mass is a good proxy for halo mass in this range and should be used preferentially whenever a halo mass selected sample is needed. For higher stellar masses, the conversion efficiency is a declining function of stellar mass, and the differences in halo mass between early-and late-types become larger, reflecting the fact that most group and cluster haloes with masses above 10 13 M host ellipticals at the centre, while even the brightest central spirals are hosted by haloes of mass below 10 13 M . We find that the fraction of spirals that are satellites is roughly 10-15 per cent independent of stellar mass or luminosity, while for ellipticals this fraction decreases with stellar mass from 50 per cent at 10 10 M to 10 per cent at 3 × 10 11 M or 20 per cent at the maximum luminosity considered. We split the elliptical sample by local density, and find that at a given luminosity there is no difference in the signal on scales below 100 h −1 kpc between high-and low-density regions, suggesting that tidal stripping inside large haloes does not remove most of the DM from the early-type satellites. This result is dominated by haloes in the mass range 10 13 -10 14 h −1 M , and is an average over all separations from the group or cluster centre.

LoCuSS: weak-lensing mass calibration of galaxy clusters

“…Note that the reduced shear ∆Σ+ is different from the definition of, for example, Mandelbaum et al (2006), because we define ∆Σ+ in terms of the reduced shear, g, and not in terms of shear, γ. The reduced tangential distortion component, g+, with respect to the cluster center is defined by The mean lensing signal for all 50 clusters as a function of the colour offset ∆C in cluster-centric radial bins.…”

“…Stacking the shear signal from a sample of clusters averages over the distribution of internal structures and halo triaxiality, and thus overcomes the structural biases suffered by some individual cluster mass measurements (e.g. Mandelbaum et al 2006;Johnston et al 2007;Okabe et al 2010aOkabe et al , 2013Umetsu et al 2011Umetsu et al , 2014Umetsu et al , 2015bOguri et al 2012;Leauthaud et al 2012;Miyatake et al 2013;Niikura et al 2015). We compute the average lensing signal in physical length unit centered on the respective BCGs.…”

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).…”

Weak lensing constraints on the dark matter haloes of early type galaxies

“…However, 72 Natarajan the most exciting results on the masses, density profiles and the galaxy-mass correlation function at the present time are from the SDSS (Sloan Digital Sky Survey). Mandelbaum and collaborators (Mandelbaum et al 2006;Hirata et al 2007) find that mass traces light on these large scales as M/L ∼ L 0.5 ; the mass of a typical dark matter (DM) halo that hosts an early-type L * galaxy is 1.5×10 12 h −1 M ; more massive DM haloes host brighter galaxies and that the masses of haloes that host late-types are a factor of 2-4 lower. Fitting parametric models they find that both NFW and Einasto profiles offer good fits over the range 0.2 r v ir < r 1 h −1 Mpc; and the inferred concentration parameter c v ir for NFW profiles is consistent with expectations of a power-law distribution with halo mass from cosmological simulations.…”