J-PLUS: Detecting and studying extragalactic globular clusters -- the case of NGC 1023

TL;DR

This study utilizes the J-PLUS survey to detect and analyze extragalactic globular clusters in NGC 1023, revealing complex stellar populations, accretion history, and galaxy interactions through a new semi-automatic detection pipeline and spectral analysis.

Contribution

The paper introduces GCFinder, a semi-automatic pipeline for detecting globular clusters in wide-field survey images, and demonstrates its application to NGC 1023, uncovering new clusters and galaxy interaction evidence.

Findings

Detected 523 GC candidates, including ~300 new ones.

Identified multiple peaks in age and metallicity distributions.

Evidence of galaxy accretion events and ongoing interactions.

Abstract

Extragalactic globular clusters (GCs) are key objects for studying the history of galaxies. The arrival of wide-field surveys such as the Javalambre Photometric Local Universe Survey (J-PLUS) offers new possibilities for the study of these systems. We perform the first study of GCs in J-PLUS to recover information about the history of NGC 1023 taking advantage of wide-field images and 12 filters. We develop the semiautomatic pipeline GCFinder that detects GC candidates in J-PLUS images and can also be adapted to similar surveys. We study the stellar population properties of a sub-sample of GC candidates using spectral energy distribution (SED) fitting. We find 523 GC candidates in NGC 1023, of which $\sim$300 are new. We identify subpopulations of GC candidates, where age and metallicity distributions have multiple peaks. By comparing our results with simulations, we report a possible broad age-metallicity relation, evidence that NGC 1023 experienced accretion events in the past. The dominating age peak is at $10^{10}$ yr. We report a correlation between masses and ages that suggests that massive GC candidates are more likely to survive the turbulent history of the host galaxy. Modeling the light of NGC 1023, we find two spiral-like arms and detect a displacement of the galaxy's photometric center with respect to the outer isophotes and center of GC distribution ($\sim$700 pc and $\sim$1600 pc, respectively), which could be the result of ongoing interaction between NGC 1023 and NGC 1023A. By studying the GC system of NGC 1023 with J-PLUS we showcase the power of multi-band surveys for this kind of study and find evidence of a complex accretion history of the host galaxy.