KMTNet Nearby Galaxy Survey: Overview and a Survey Description

TL;DR

This paper presents the KMTNet Nearby Galaxy Survey, which provides deep, wide-field optical and Hα imaging of 13 nearby galaxies to study low surface brightness features and galaxy evolution.

Contribution

It introduces a new deep imaging survey of nearby galaxies with unprecedented surface brightness limits, enabling detailed studies of galaxy merger remnants and star formation in outer disks.

Findings

Achieved surface brightness limits of 29-31 mag arcsec$^{-2}$ in optical bands.

Provided deep Hα imaging with flux limits of 1-2×10$^{-18}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$.

Survey data supports studies of galaxy mass assembly and disk evolution.

Abstract

Recently, there has been an increasing demand for deep imaging surveys to investigate the history of the mass assembly of galaxies in detail by examining the remnants of mergers and accretions, both of which have very low surface brightness (LSB). In addition, the nature of star formation in LSB regions, such as galaxy outer disks, is also an intriguing topic in terms of understanding the physical mechanisms of disk evolution. To address these issues, this study conducts a survey project, called the Korea Microlensing Telescope Network (KMTNet) Nearby Galaxy Survey to construct a deep imaging data set of nearby galaxies in the southern hemisphere using KMTNet. It provides deep and wide-field images with a field-of-view of $\sim$12 deg$^2$ for 13 nearby galaxies drawn from the Carnegie-Irvine Galaxy Survey catalog, in optical broadbands ($BRI$) and an H$\alpha$ narrowband. Through a dedicated data reduction, the surface brightness limit in 10$^{\prime\prime}\times10^{\prime\prime}$ boxes was found to reach as deep as $\mu_{1\sigma}\sim29$-31 mag arcsec$^{-2}$ in the optical broadbands and $f_{1\sigma}\sim1$-$2\times 10^{-18}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$ in the H$\alpha$ narrowband. To conclude the paper, several possible scientific applications for this data set are described.