Towards a new classification of early-type galaxies: an integral-field view

TL;DR

This paper introduces a new kinematic classification for early-type galaxies based on two-dimensional stellar velocity maps, distinguishing between slow and fast rotators using a novel parameter, LambdaR.

Contribution

The study proposes a new classification scheme for early-type galaxies based on integral-field spectroscopic data, emphasizing the role of large-scale rotation.

Findings

Early-type galaxies can be classified into slow and fast rotators.

The LambdaR parameter effectively distinguishes between the two classes.

Photometric properties support the kinematic classification.

Abstract

In this proceeding we make use of the two-dimensional stellar kinematics of a representative sample of E and S0 galaxies obtained with the SAURON integral-field spectrograph to reveal that early-type galaxies appear in two broad flavours, depending on whether they exhibit clear large-scale rotation or not. We measure the level of rotation via a new parameter LambdaR and use it as a basis for a new kinematic classification that separates early-type galaxies into slow and fast rotators. With the aid of broad-band imaging we will reinforce this finding by comparing our kinematic results to the photometric properties of these two classes.