# A Redshift Survey of the Nearby Galaxy Cluster Abell 2199: Comparison of the Spatial and Kinematic Distributions of Galaxies with the Intracluster Medium

## TL;DR

This study conducts a comprehensive redshift survey of galaxy cluster Abell 2199, comparing galaxy kinematics and distribution with the intracluster medium, revealing insights into cluster dynamics and structure.

## Contribution

It provides the first extensive spectroscopic dataset for A2199's central region, enabling detailed comparison of galaxy and intracluster medium properties.

## Key findings

- Galaxy velocity dispersion profile smoothly connects to the cD galaxy's stellar velocity dispersion.
- General agreement between galaxy and ICM velocities, with some localized differences.
- Detection of potential global rotation in galaxy distribution not seen in ICM.

## Abstract

We present the results from an extensive spectroscopic survey of the central region of the nearby galaxy cluster Abell 2199 at $z=0.03$. By combining 775 new redshifts from the MMT/Hectospec observations with the data in the literature, we construct a large sample of 1624 galaxies with measured redshifts at $R<30^\prime$, which results in high spectroscopic completeness at $r_{\rm petro,0}<20.5$ (77%). We use these data to study the kinematics and clustering of galaxies focusing on the comparison with those of the intracluster medium (ICM) from Suzaku X-ray observations. We identify 406 member galaxies of A2199 at $R<30^\prime$ using the caustic technique. The velocity dispersion profile of cluster members appears smoothly connected to the stellar velocity dispersion profile of the cD galaxy. The luminosity function is well fitted with a Schechter function at $M_r<-15$. The radial velocities of cluster galaxies generally agree well with those of the ICM, but there are some regions where the velocity difference between the two is about a few hundred kilometer per second. The cluster galaxies show a hint of global rotation at $R<5^\prime$ with $v_{\rm rot}=300{-}600\,\textrm{km s}^{-1}$, but the ICM in the same region do not show such rotation. We apply a friends-of-friends algorithm to the cluster galaxy sample at $R<60^\prime$ and identify 32 group candidates, and examine the spatial correlation between the galaxy groups and X-ray emission. This extensive survey in the central region of A2199 provides an important basis for future studies of interplay among the galaxies, the ICM and the dark matter in the cluster.