Galaxy And Mass Assembly (GAMA): the halo mass of galaxy groups from maximum-likelihood weak lensing

Jiaxin Han*, Vincent R. Eke, Carlos S. Frenk, Rachel Mandelbaum, Peder Norberg, Michael D. Schneider, John A. Peacock, Yipeng Jing, Ivan Baldry, Joss Bland-Hawthorn, Sarah Brough, Michael J. I. Brown, Jochen Liske, Jon Loveday, Aaron S. G. Robotham

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We present a maximum-likelihood weak-lensing analysis of the mass distribution in optically selected spectroscopic Galaxy Groups (G(3)Cv5) in the Galaxy And Mass Assembly (GAMA) survey, using background Sloan Digital Sky Survey (SDSS) photometric galaxies. The scaling of halo mass, M-h, with various group observables is investigated. Our main results are as follows. (1) The measured relations of halo mass with group luminosity, virial volume and central galaxy stellar mass, M-*, agree very well with predictions from mock group catalogues constructed from a GALFORM semi-analytical galaxy formation model implemented in the Millennium Lambda CDM N-body simulation. (2) The measured relations of halo mass with velocity dispersion and projected half-abundance radius show weak tension with mock predictions, hinting at problems in the mock galaxy dynamics and their small-scale distribution. (3) The median M-h vertical bar M-* measured from weak lensing depends more sensitively on the lognormal dispersion in M-* at fixed Mh than it does on the median M-*vertical bar M-h. Our measurements suggest an intrinsic dispersion of sigma(log(M star)) similar to 0.15. (4) Comparing our mass estimates with those in the catalogue, we find that the G(3)Cv5 mass can give biased results when used to select subsets of the group sample. Of the various new halo-mass estimators that we calibrate using our weak-lensing measurements, group luminosity is the best single-proxy estimator of group mass.

Original languageEnglish
Pages (from-to)1356-1379
Number of pages24
JournalMonthly Notices of the Royal Astronomical Society
Volume446
Issue number2
DOIs
Publication statusPublished - 11 Jan 2015

Keywords

  • gravitational lensing: weak
  • methods: data analysis
  • dark matter
  • galaxies: clusters
  • DARK-MATTER HALOES
  • DIGITAL SKY SURVEY
  • LARGE-SCALE STRUCTURE
  • K-BAND PROPERTIES
  • STELLAR MASS
  • LUMINOSITY FUNCTION
  • RADIAL-DISTRIBUTION
  • REDSHIFT SURVEY
  • STAR-FORMATION
  • OCCUPATION DISTRIBUTION

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