The Rotation of Selected Globular Clusters and the Differential Rotation of M3 in Multiple Populations from the SDSS-IV APOGEE-2 Survey

TL;DR

This study measures the rotation of 9 globular clusters using SDSS-IV APOGEE-2 data, revealing significant differences in the rotational properties of multiple populations in M3, and confirming theoretical predictions.

Contribution

First measurement of differential rotation between stellar populations in M3, validating numerical simulation predictions and expanding understanding of globular cluster dynamics.

Findings

M3 shows significant difference in rotation between populations.

Good agreement with previous rotation measurements.

Detected smaller deviations in other clusters, within error margins.

Abstract

In this paper, we analyze 10 globular clusters in order to measure their rotational properties by using high precision radial velocity data from the SDSS-IV APOGEE-2 survey. Out of the 10 clusters we were able to successfully measure the rotation speed and position angle of the rotation axis for 9 clusters (M2, M3, M5, M12, M13, M15, M53, M92, M107). The comparison between our results and previous ones shows a really good agreement within our uncertainties. For four of the globular clusters, M3, M13, M5 and M15, we separated the sample into two generation of stars using their [Al/Fe] abundances and examined the kinematic features of these generations separately from one another. In case of M3, we found significant difference between the rotational properties of first and second populations, confirming for the first time the predictions of several numerical simulations from the literature. The other three clusters (M5, M13, M15) also show smaller deviation between the two groups of stars, but those deviations are comparable to our errors.