A kinematically distinct core and minor-axis rotation: the MUSE perspective on M87

TL;DR

This study reveals a complex, non-axisymmetric kinematic structure in M87, including a kinematically distinct core and significant rotation twist, using advanced integral-field spectroscopy to inform galaxy formation models.

Contribution

It provides new detailed kinematic maps of M87's core, demonstrating the galaxy's complex shape and orbital structure with MUSE data, advancing understanding of galaxy assembly.

Findings

Detection of a low-amplitude kinematically distinct core

Identification of a 140-degree velocity twist within the central region

Evidence for a prolate-like rotation around the galaxy's major axis

Abstract

We present evidence for the presence of a low-amplitude kinematically distinct component in the giant early-type galaxy M87, via datasets obtained with the SAURON and MUSE integral-field spectroscopic units. The MUSE velocity field reveals a strong twist of ~140 deg within the central 30 arcsec connecting outwards such a kinematically distinct core to a prolate-like rotation around the large-scale photometric major-axis of the galaxy. The existence of these kinematic features within the apparently round central regions of M87 implies a non-axisymmetric and complex shape for this galaxy, which could be further constrained using the presented kinematics. The associated orbital structure should be interpreted together with other tracers of the gravitational potential probed at larger scales (e.g., Globular Clusters, Ultra Compact Dwarfs, Planetary Nebulae): it would offer an insight in the assembly history of one of the brightest galaxies in the Virgo Cluster. These data also demonstrate the potential of the MUSE spectrograph to uncover low-amplitude spectral signatures.