Detection of open cluster rotation fields from Gaia EDR3 proper motions

Abstract

Context. Most stars from in groups which with time disperse, building the field population of their host galaxy. In the Milky Way, open clusters have been continuously forming in the disk up to the present time, providing it with stars spanning a broad range of ages and masses. Observations of the details of cluster dissolution are, however, scarce. One of the main difficulties is obtaining a detailed characterisation of the internal cluster kinematics, which requires very high quality proper motions. For open clusters, which are typically loose groups with some tens to hundreds of members, there is the additional difficulty of inferring kinematic structures from sparse and irregular distributions of stars. Aims. Here, we aim to analyse internal stellar kinematics of open clusters, and identify rotation, expansion or contraction patterns. Methods. We use Gaia Early Data Release 3 (EDR3) astrometry and Integrated Nested Laplace Approximations to perform vector-field inference and create spatio-kinematic maps of 1237 open clusters. The sample is composed of clusters for which individual stellar memberships were known, thus minimising contamination from field stars in the velocity maps. Projection effects were corrected using EDR3 data complemented with radial velocities from Gaia Data Release 2 and other surveys. Results. We report the detection of rotation patterns in 8 open clusters. Nine additional clusters display possible rotation signs. We also observe 14 expanding clusters, with 15 other objects showing possible expansion patterns. Contraction is evident in two clusters, with one additional cluster presenting a more uncertain detection. In total, 53 clusters are found to display kinematic structures. Within these, elongated spatial distributions suggesting tidal tails are found in 5 clusters. [abridged]

7 pages main article + 29 pages in appendices. Published in A&A

References in corpus (15)

• The Gaia mission
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• The Radial Velocity Experiment (RAVE): Fifth Data Release
• Gaia EDR3 view on Galactic globular clusters
• Updated parameters of 1743 open clusters based on Gaia DR2
• Age determination for 269 $Gaia$ DR2 Open Clusters
• Lifetimes of tidally limited star clusters with different radii
• Extended stellar systems in the solar neighborhood - I. The tidal tails of the Hyades
• The eye of Gaia on globular clusters kinematics: internal rotation
• Hubble Space Telescope Proper Motion (HSTPROMO) Catalogs of Galactic Globular Clusters. V. The rapid rotation of 47 Tuc traced and modeled in three dimensions
• Evidence of tidal distortions and mass loss from the old open cluster NGC 6791
• Theia: Faint objects in motion or the new astrometry frontier
• Tails and streams around the Galactic globular clusters NGC1851, NGC1904, NGC2298 and NGC2808
• 3D core kinematics of NGC 6362: central rotation in a dynamically evolved globular cluster
• The Rotation of Selected Globular Clusters and the Differential Rotation of M3 in Multiple Populations from the SDSS-IV APOGEE-2 Survey

Cited by in corpus (8)

• Tidal tails of open clusters
• The spin, expansion and contraction of open star clusters
• Expansion Kinematics of Young Clusters. I. Lambda Ori
• Open cluster dissolution rate and the initial cluster mass function in the solar neighbourhood. Modelling the age and mass distributions of clusters observed by Gaia
• Bayesian ages of local young stellar associations I. Through the expansion rate method
• $R_V$ from multi-waveband galaxy polarimetry in supernovae vicinity
• Internal dynamics and structure of Cepheus OB4. The asymmetric expansion of Berkeley 59
• Right round: onset and long-term evolution of rotation in star clusters