Cosmology with velocity dispersion counts: an alternative to measuring cluster halo masses
| Autor: | Chris A. Collins, Ivan K. Baldry, Simeon Bird, Ian G. McCarthy, Joop Schaye, Caroline Caldwell |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Physics
Cosmology and Nongalactic Astrophysics (astro-ph.CO) Cosmic microwave background Halo mass function FOS: Physical sciences Velocity dispersion Astronomy and Astrophysics Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Galaxy Cosmology Redshift Space and Planetary Science 0103 physical sciences Halo 010306 general physics 010303 astronomy & astrophysics Galaxy cluster Astrophysics - Cosmology and Nongalactic Astrophysics |
| Zdroj: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY NASA Astrophysics Data System MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 462, 4117-4129 |
| Popis: | The evolution of galaxy cluster counts is a powerful probe of several fundamental cosmological parameters. A number of recent studies using this probe have claimed tension with the cosmology preferred by the analysis of the Planck primary CMB data, in the sense that there are fewer clusters observed than predicted based on the primary CMB cosmology. One possible resolution to this problem is systematic errors in the absolute halo mass calibration in cluster studies, which is required to convert the standard theoretical prediction (the halo mass function) into counts as a function of the observable (e.g., X-ray luminosity, Sunyaev-Zel'dovich flux, optical richness). Here we propose an alternative strategy, which is to directly compare predicted and observed cluster counts as a function of the one-dimensional velocity dispersion of the cluster galaxies. We argue that the velocity dispersion of groups/clusters can be theoretically predicted as robustly as mass but, unlike mass, it can also be directly observed, thus circumventing the main systematic bias in traditional cluster counts studies. With the aid of the BAHAMAS suite of cosmological hydrodynamical simulations, we demonstrate the potential of the velocity dispersion counts for discriminating even similar $\Lambda$CDM models. These predictions can be compared with the results from existing redshift surveys such as the highly-complete Galaxy And Mass Assembly (GAMA) survey, and upcoming wide-field spectroscopic surveys such as the Wide Area Vista Extragalactic Survey (WAVES) and the Dark Energy Survey Instrument (DESI). Comment: 15 pages, 13 figures. Accepted for publication in MNRAS. New section on cosmological forecasts added |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|