Mass Segregation in the CMZoom Survey

TL;DR

This study uses a Minimum Spanning Tree approach to analyze the spatial distribution and mass segregation of compact sources in the Central Molecular Zone, revealing varied segregation patterns across clouds.

Contribution

It introduces a MST-based method to quantify mass segregation in CMZ clouds and compares these patterns with star formation activity and evolutionary stages.

Findings

Some clouds show significant mass segregation (Λ_MSR > 1.5).

Others exhibit inverse or no mass segregation.

Mass segregation does not strongly correlate with star formation activity.

Abstract

We employ a Minimum Spanning Tree (MST) approach to characterize the spatial distribution and mass segregation of compact millimeter continuum sources within the Central Molecular Zone (CMZ) of the Milky Way. We use a modified form of the complete version of the 1.3 mm dust continuum catalog from the CMZoom survey, which identifies 685 compact sources with typical effective radii of $\sim0.1$ pc. For 22 of 35 CMZ clouds, we calculate the thermal and turbulent Jeans lengths and masses, and determine that compact source separations, as well as compact source masses, are more consistent with thermal fragmentation at $\sim0.1$ pc size scales. We construct the mass segregation ratios for compact sources in 17 CMZ clouds and determine that 5 of the analyzed clouds display some form of mass segregation ($\Lambda_{MSR} > 1.5$), while the remaining clouds show either inverse mass segregation ($\Lambda_{MSR} < 0.75$), or no evidence of true mass segregation ($0.75 < \Lambda_{MSR} < 1.5$). Finally, we find that although some actively star-forming clouds do exhibit mass segregation, other similarly active clouds do not, indicating an unclear correlation with evolutionary stage for star forming clouds in the CMZ, given the current available data.