Star Clusters in the Nearby Late-Type Galaxy NGC 1311

TL;DR

This study uses Hubble Space Telescope images to identify and analyze a small population of star clusters in galaxy NGC 1311, revealing their ages, masses, and formation history.

Contribution

It provides the first detailed characterization of star clusters in NGC 1311, showing their mass-age relationship and episodic formation in a nearby dwarf galaxy.

Findings

Cluster masses range from 1,000 to 100,000 solar masses.

Cluster ages indicate multiple formation episodes at ~10 Myr, ~100 Myr, and ~1 Gyr.

No evidence of super star clusters typical of starburst galaxies.

Abstract

Ultraviolet, optical and near infrared images of the nearby (D ~ 5.5 Mpc) SBm galaxy NGC 1311, obtained with the Hubble Space Telescope, reveal a small population of 13 candidate star clusters. We identify candidate star clusters based on a combination of their luminosity, extent and spectral energy distribution. The masses of the cluster candidates range from ~1000 up to ~100000 Solar masses, and show a strong positive trend of larger mass with increasing with cluster age. Such a trend follows from the fading and dissolution of old, low-mass clusters, and the lack of any young super star clusters of the sort often formed in strong starbursts. The cluster age distribution is consistent with a bursting mode of cluster formation, with active episodes of age ~10 Myr, ~100 Myr and ~1 Gyr. The ranges of age and mass we probe are consistent with those of the star clusters found in quiescent Local Group dwarf galaxies.