Open AccessAn improved method for the identification of galaxy systems: measuring the gravitational redshift by dark matter haloes
Author(s) -
Domínguez Romero Mariano Javier de León,
García Lambas Diego,
Muriel Hernán
Publication year - 2012
Publication title -
monthly notices of the royal astronomical society: letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.067
H-Index - 122
eISSN - 1745-3933
pISSN - 1745-3925
DOI - 10.1111/j.1745-3933.2012.01326.x
Subject(s) - physics , dark matter , astrophysics , redshift , galaxy , halo , dark matter halo , redshift survey , gravitation , general relativity , astronomy , theoretical physics
We introduce a new method for the identification of galaxy systems in redshift surveys based on the halo model. This method is a modified version of the K ‐means identification algorithm developed by Yang et al. We have calibrated and tested our algorithms using mock catalogues generated using the Millennium Simulations and applied them to the NYU‐DR7 galaxy catalogue (based on the SDSS data sets). Using this local sample of groups and clusters of galaxies, we have measured the effect of gravitational redshift produced by their host dark matter haloes. Our results show radial velocity decrements consistent with general relativity predictions and previous measurements by Wojtak et al. in clusters of galaxies.