Biases in the estimation of velocity dispersions and dynamical masses for galaxy clusters

Abstract

Using a set of 73 numerically simulated galaxy clusters, we have characterised the statistical and physical biases for three velocity dispersion and mass estimators, namely biweight, gapper and standard deviation, in the small number of galaxies regime ($N_{gal}\le 75$), both for the determination of the velocity dispersion and the dynamical mass of the clusters via the $\sigma -M$ relation. These results are used to define a new set of unbiased estimators, that are able to correct for those statistical biases. By applying these new estimators to a subset of simulated observations, we show that they can retrieve bias-corrected values for both the mean velocity dispersion and the mean mass.

6 pages, 7 figures, to appear in the proceedings of the international conference entitled mm Universe @ NIKA2, Grenoble (France), June 2019, EPJ Web of conferences

References in corpus (4)

• Virial Scaling of Massive Dark Matter Halos: Why Clusters Prefer a High Normalization Cosmology
• The galaxy cluster mass scale and its impact on cosmological constraints from the cluster population
• The relation between velocity dispersion and mass in simulated clusters of galaxies: dependence on the tracer and the baryonic physics
• The universal distribution of halo interlopers in projected phase space. Bias in galaxy cluster concentration and velocity anisotropy?

Cited by in corpus (3)

• SPIDERS: An Overview of The Largest Catalogue of Spectroscopically Confirmed X-ray Galaxy Clusters
• Boosting the evolutionary picture of Cl 0024+17 and MS 0451-03: A case study at intermediate-redshift
• Galaxy Velocity Bias in Cosmological Simulations: Towards Percent-level Calibration