The Star Cluster Population of M51: III. Cluster disruption and formation history

TL;DR

This study investigates the evolution of star clusters in galaxy M51, focusing on their disruption timescales and formation history, revealing increased formation during galaxy encounters and shorter-than-expected disruption times.

Contribution

It introduces a method to compare observed cluster populations with models, accounting for formation rate variations and physical disruption parameters, applied to M51.

Findings

Cluster formation rate increases during galaxy encounters.

Disruption timescale is shorter than theoretical predictions.

Young globular clusters are unlikely to survive long in M51's disk.

Abstract

In this work we concentrate on the evolution of the cluster population of the interacting galaxy M51 (NGC 5194), namely the timescale of cluster disruption and possible variations in the cluster formation rate. We present a method to compare observed age vs. mass number density diagrams with predicted populations including various physical input parameters like the cluster initial mass function, cluster disruption, cluster formation rate and star bursts. If we assume that the cluster formation rate increases at the moments of the encounters with NGC 5195, we find an increase in the cluster formation rate of a factor of 3, combined with a disruption timescale which is slightly higher then when assuming a constant formation rate (t_4 = 200 Myr vs. 100 Myr). The measured cluster disruption time is a factor of 5 shorter than expected on theoretical grounds. This implies that the disk of M51 is not a preferred location for survival of young globular clusters, since even clusters with masses of the order of 10^6 M_sun will be destroyed within a few Gyr.