Young massive star clusters in nearby galaxies. II.Software tools, data reductions and cluster sizes

TL;DR

This paper details the data analysis process for discovering young massive star clusters in 21 nearby galaxies, introduces the ishape tool for size estimation, and provides comprehensive photometric data and cluster size measurements.

Contribution

It introduces the ishape software tool for deriving intrinsic shape parameters of compact objects and applies it to estimate cluster sizes in galaxy samples.

Findings

Half-light radii of 0-20 pc for clusters in NGC 1313 and NGC 5236

ishape tool effectively estimates cluster sizes and shapes

Photometric data and cluster parameters are systematically tabulated

Abstract

A detailed description is given of the data analysis leading to the discovery of young massive star clusters (YMCs) in a sample of 21 nearby galaxies. A new useful tool, ishape, for the derivation of intrinsic shape parameters of compact objects is presented, and some test results are shown. Completeness tests for the cluster samples are discussed, and ishape is used to estimate cluster sizes. Half-light radii of 0 - 20 pc are derived for clusters in 2 of the most cluster-rich galaxies, NGC 1313 and NGC 5236, which is within the range spanned by globular clusters in the Milky Way and by YMCs in the LMC and some starburst galaxies. Photometric data for all clusters, along with positions and estimated half-light radii, are tabulated.