MUSE narrow field mode observations of the central kinematics of M15

TL;DR

This study uses high-resolution MUSE observations with adaptive optics to analyze the complex central stellar kinematics of globular cluster M15, revealing detailed rotational structures and confirming previous suggestions of kinematic complexity.

Contribution

It provides the largest sample of radial velocities in M15's core and confirms complex kinematic features with higher significance using advanced integral field spectroscopy.

Findings

Central kinematics are complex with offset rotation axes.

Confirmed higher significance of kinematic complexity.

Largest radial velocity sample for M15's core.

Abstract

We present observations of the stellar kinematics of the centre of the core collapsed globular cluster M15 obtained with the MUSE integral field spectrograph on the VLT operating in narrow field mode. Thanks to the use of adaptive optics, we obtain a spatial resolution of 0.1arcsec and are able to reliably measure the radial velocities of 864 stars within 8 arcsec of the centre of M15 thus providing the largest sample of radial velocities ever obtained for the innermost regions of this system. Combined with previous observations of M15 using MUSE in wide field mode and literature data, we find that the central kinematics of M15 are complex with the rotation axis of the core of M15 offset from the rotation axis of the bulk of the cluster. While this complexity has been suggested by previous work, we confirm it at higher significance and in more detail.