VLT/MAGELLAN SPECTROSCOPY of 29 STRONG LENSING SELECTED GALAXY CLUSTERS

Mauricio Carrasco, L. Felipe Barrientos, Timo Anguita, Cristina García-Vergara, Matthew Bayliss, Michael Gladders, David Gilbank, H. K.C. Yee, Michael West

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

We present an extensive spectroscopic follow-up campaign of 29 strong lensing (SL) selected galaxy clusters discovered primarily in the Second Red-Sequence Cluster Survey (RCS-2). Our spectroscopic analysis yields redshifts for 52 gravitational arcs present in the core of our galaxy clusters, which correspond to 35 distinct background sources that are clearly distorted by the gravitational potential of these clusters. These lensed galaxies span a wide redshift range of 0.8 ≤ z ≤ 2.9, with a median redshift of z s = 1.8 ± 0.1. We also measure reliable redshifts for 1004 cluster members, allowing us to obtain robust velocity dispersion measurements for 23 of these clusters, which we then use to determine their dynamical masses by using a simulation-based σ DM - M 200 scaling relation. The redshift and mass ranges covered by our SL sample are 0.22 ≤ z ≤ 1.01 and , respectively. We analyze and quantify some possible effects that might bias our mass estimates, such as the presence of substructure, the region where cluster members are selected for spectroscopic follow-up, the final number of confirmed members, and line-of-sight effects. We find that 10 clusters of our sample with N mem 20 show signs of dynamical substructure. However, the velocity data of only one system is inconsistent with a uni-modal distribution. We therefore assume that the substructures are only marginal and not of comparable size to the clusters themselves. Consequently, our velocity dispersion and mass estimates can be used as priors for SL mass reconstruction studies and also represent an important step toward a better understanding of the properties of the SL galaxy cluster population.

Original languageEnglish
Article number210
JournalAstrophysical Journal
Volume834
Issue number2
DOIs
Publication statusPublished - 10 Jan 2017

Keywords

  • dark matter
  • galaxies: clusters: general
  • galaxies: evolution
  • galaxies: kinematics and dynamics
  • gravitational lensing: strong

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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