Destruction of star clusters due to the radial migration in spiral galaxies

TL;DR

This study uses N-body simulations to show that star clusters in spiral galaxies migrate radially due to spiral arm interactions, leading to their rapid disruption in inner regions and formation of detectable tidal tails.

Contribution

It demonstrates the impact of transient spiral arms on star cluster migration and disruption, highlighting the importance of radial migration in cluster evolution within galactic disks.

Findings

Star clusters migrate radially over a few hundred Myr.

Disruption timescales are shortened in inner galaxy regions.

Tidal tails extend over 1-2 kpc and can be identified via velocity plots.

Abstract

Most stars in galactic disks are believed to be born as a member of star clusters or associations. Star clusters formed in disks are disrupted due to the tidal stripping and the evolution of star clusters themselves, and as a results new stars are supplied to the galactic disks. We performed $N$-body simulations of star clusters in galactic disks, in which both star clusters and galactic disks are modeled as $N$-body ("live") systems, and as a consequence the disks form transient and recurrent spiral arms. In such non-steady spiral arms, star clusters migrate radially due to the interaction with spiral arms. We found that the migration timescale is a few hundreds Myr and that the angular momentum changes of star clusters are at most $\sim 50$% in 1 Gyr. Radial migration of star clusters to the inner region of galaxies results in a fast disruption of the star clusters because of a stronger tidal field in the inner region of the galaxy. This effect is not negligible for the disruption timescale of star clusters in galactic disks. Stars stripped from clusters form tidal tails which spread over 1--2 kpc. While the spatial distribution of tidal tails change in a complicated way due to the non-steady spiral arms, the velocity distribution conserve well even if the tidal tails are located at a few kpc from their parent clusters. Tidal tails of clusters in galactic disks might be detected using velocity plots.