The masses of satellites in GAMA galaxy groups from 100 square degrees of KiDS weak lensing data

• Published in: Monthly notices of the Royal Astronomical Society Vol. 454; no. 4; pp. 3938 - 3951
• Main Authors: Sifón, Cristóbal, Cacciato, Marcello, Hoekstra, Henk, Brouwer, Margot, van Uitert, Edo, Viola, Massimo, Baldry, Ivan, Brough, Sarah, Brown, Michael J. I., Choi, Ami, Driver, Simon P., Erben, Thomas, Grado, Aniello, Heymans, Catherine, Hildebrandt, Hendrik, Joachimi, Benjamin, de Jong, Jelte T. A., Kuijken, Konrad, McFarland, John, Miller, Lance, Nakajima, Reiko, Napolitano, Nicola, Norberg, Peder, Robotham, Aaron S. G., Schneider, Peter, Kleijn, Gijs Verdoes
• Format: Journal Article
• Language: English
• Published: London Oxford University Press 21-12-2015
• Subjects: Astronomical models; Astronomy; Cold; Dark matter; Density; Galactic halos; Galaxies; Satellites; Stars & galaxies; Stellar mass; Universe; methods: observational; methods: statistical; gravitational lensing: weak; galaxies: statistics; dark matter; galaxies: haloes
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stv2051

We use the first 100 deg2 of overlap between the Kilo-Degree Survey and the Galaxy And Mass Assembly survey to determine the average galaxy halo mass of ∼10 000 spectroscopically confirmed satellite galaxies in massive (M > 1013 h
−1 M⊙) galaxy groups. Separating the sample as a function of projected distance to the group centre, we jointly model the satellites and their host groups with Navarro–Frenk–White density profiles, fully accounting for the data covariance. The probed satellite galaxies in these groups have total masses log 〈M
sub/(h
−1 M⊙)〉 ≈ 11.7–12.2 consistent across group-centric distance within the errorbars. Given their typical stellar masses, log 〈M
⋆, sat/(h
−2 M⊙)〉 ∼ 10.5, such total masses imply stellar mass fractions of 〈M
⋆, sat〉/〈M
sub〉 ≈ 0.04 h
−1. The average subhalo hosting these satellite galaxies has a mass M
sub ∼ 0.015M
host independent of host halo mass, in broad agreement with the expectations of structure formation in a Λ cold dark matter universe.