Weak-lensing analysis of a new galaxy group sample

ELIZABETH JOHANA GONZALEZ; FACUNDO RODRIGUEZ; MANUEL MERCHÁN; DIEGO GARCIA LAMBAS; MARTÍN MAKLER

Rosario

Congreso; 62ª Reunión Anual de la Asociación Argentina de Astronomía; 2020

Universidad Nacional de Rosario

In this work, we analyse a sample of spectroscopic selected galaxy groups identified according to an algorithm based on a combination of percolation and halo-based methods. Groups are identified using the spectroscopic data of the Sloan Digital Sky Survey Data Release 12 and spans over a wide range of richness and masses, mostly including low-richness galaxy systems. We select a sample of these groups and performed a lensing analysis in order to estimate the total halo masses considering the brightest galaxy member (BGM) as the halo centre. We model the lensing signal considering a fraction of miss-centred groups and evaluate how this fraction is related to a wrong membership assignment using simulated data. Then, we compare derived masses with the estimates provided in the catalogue, computed according to the abundance matching technique and to the line-of-sight velocity dispersion. We inspect the relation between these mass proxies and the lensing estimates and how this relation is biased according to the redshift and the group richness. Since the mass proxy provided in the catalogue relies on the membership assignment by the identification algorithm, the analysis allows us to test its performance as well as to study the relation between the total halo masses and the mentioned proxies. This study enables to constrain observational mass proxies, especially for low-richness galaxy systems.