Inferring Globular Cluster Initial Mass Function from Stellar Streams

TL;DR

This study uses Gaia data and simulations to infer the initial mass function of globular clusters from stellar streams, revealing a power-law distribution with a slope of approximately 1.3.

Contribution

It introduces a method combining observations and simulations to determine the initial mass function of globular clusters from stellar streams.

Findings

Initial cluster mass function follows a power-law with slope ~1.3.

More massive clusters produce more massive but less mass-efficient streams.

Stellar streams serve as a new probe of early globular cluster mass distribution.

Abstract

The Gaia mission has provided precise astrometry and spectrophotometry for billions of stars in the Milky Way, enabling the identification and kinematic characterization of stellar streams. These streams, remnants of disrupted globular clusters and dwarf galaxies, have revealed the structure of the Milky Way's dark matter halo. We show that stellar streams also encode information about the initial mass function of globular clusters. We combine cold dark matter simulations that model the evolution and disruption of embedded globular clusters with observations of stellar streams and globular clusters to infer the initial cluster mass function. We find that initially more massive clusters produce more massive streams, but deposit a smaller fraction of their initial mass into those streams. Using stream mass and angular momentum measurements, we recover a declining, power-law-like initial mass function with a slope $\alpha = 1.3\pm0.05$ for streams $\gtrsim 1000\,M_{\odot}$. This work establishes stellar streams as a novel probe of the early mass distribution of globular clusters.