Fast and slow rotators in the densest environments: a FLAMES/GIRAFFE IFS study of galaxies in Abell 1689 at z=0.183

TL;DR

This study uses integral field spectroscopy to analyze galaxy kinematics in Abell 1689, revealing that the fraction of slow rotators is similar to that in Virgo and increases towards the cluster center, extending the kinematic morphology-density relation.

Contribution

It demonstrates that existing instruments can identify slow and fast rotators in distant clusters, extending the kinematic morphology-density relation beyond the local Universe.

Findings

Slow rotator fraction in Abell 1689 is 0.15, similar to Virgo.

Slow rotators are more common towards the cluster center.

The kinematic morphology-density relation extends to higher densities.

Abstract

We present FLAMES/GIRAFFE integral field spectroscopy of 30 galaxies in the massive cluster Abell 1689 at z = 0.183. Conducting an analysis similar to that of ATLAS3D, we extend the baseline of the kinematic morphology-density relation by an order of magnitude in projected density and show that it is possible to use existing instruments to identify slow and fast rotators beyond the local Universe. We find 4.5 +- 1.0 slow rotators with a distribution in magnitude similar to those in the Virgo cluster. The overall slow rotator fraction of our Abell 1689 sample is 0.15 +- 0.03, the same as in Virgo using our selection criteria. This suggests that the fraction of slow rotators in a cluster is not strongly dependent on its density. However, within Abell 1689, we find that the fraction of slow rotators increases towards the centre, as was also found in the Virgo cluster.