Detailed study of galaxies with the stellar counter-rotation phenomenon

TL;DR

This study investigates galaxies with counter-rotating stellar discs to understand their formation and evolution, revealing a mass-dependent dichotomy in their properties through analysis of MaNGA survey data.

Contribution

It provides the first comprehensive analysis of counter-rotating galaxies' stellar populations, highlighting differences based on galaxy mass and suggesting varied evolutionary histories.

Findings

Most massive galaxies have extended counter-rotating disks.

Counter-rotating disk contribution is higher in more massive galaxies.

Sample shows a dichotomy in properties based on galaxy mass.

Abstract

The process of galactic disc growing is still not fully understood. In the majority of disk galaxies the gas and stars are located in the same plane and rotate in the same direction. However, there are kinematically peculiar galaxies hosting two counter-rotating stellar discs. Their origin is believed to be the result of a past event of accretion of gas followed by star formation. By studying such galaxies we can learn how much material, when, and how, have fallen onto the progenitor galaxy. We identified a sample of 56 counter-rotating galaxies in the MaNGA IFU survey and initiated a follow-up observing campaign at the 6-m telescope (BTA) aiming to determine the stellar population properties of both stellar discs. Our preliminary results suggest the dichotomy of the sample of counter-rotating galaxies. We found that most massive galaxies have extended counter-rotating disks, whose contribution to luminosity is higher than in the less massive galaxies suggestive of different evolutionary paths.