Evidence of an interaction from resolved stellar populations: The curious case of NGC1313

TL;DR

This study uses resolved stellar populations from HST data to investigate the peculiar morphology of NGC1313, providing evidence of a localized interaction with a satellite galaxy that influenced recent star formation.

Contribution

It offers new insights into NGC1313's interaction history by analyzing star formation histories across different regions using resolved stellar populations.

Findings

Evidence of a recent starburst in the south-west region.

Detection of a tidally disrupted satellite galaxy.

No global perturbation observed across the galaxy.

Abstract

The galaxy NGC1313 has attracted the attention of various studies due to the peculiar morphology observed in optical bands, although it is classified as a barred, late-type galaxy with no apparent close-by companions. However, the velocity field suggests an interaction with a satellite companion. Using resolved stellar populations, we study different parts of the galaxy to understand further its morphology. Based on HST/ACS images, we estimated star formation histories by means of the synthetic CMD method in different areas in the galaxy. Incompleteness limits our analysis to ages younger than ~100Myr. Stars in the red and blue He burning phases are used to trace the distribution of recent star formation. Star formation histories suggest a burst in the southern-west region. We support the idea that NGC1313 is experiencing an interaction with a satellite companion, observed as a tidally disrupted satellite galaxy in the south-west of NGC1313. However, we do not observe any indication of a perturbation due to the interaction with the satellite galaxy at other locations across the galaxy, suggesting that only a modest-sized companion that did not trigger a global starburst was involved.