The ASAS-SN Low Surface Brightness Survey I: Proof-of-Concept and Potential Applications

TL;DR

The ASAS-SN Low Surface Brightness Survey leverages 7 years of data to produce deep, wide-field images revealing faint structures in the Milky Way and nearby galaxies, enabling new astrophysical discoveries.

Contribution

This paper presents a novel deep imaging survey using existing data to explore low surface brightness phenomena across the entire sky.

Findings

Achieved a median surface brightness limit of 26.1 mag arcsec$^{-2}$.

Recovered 82% of known ultra-diffuse galaxies in the survey.

Demonstrated the survey's capability to image large-scale diffuse structures.

Abstract

The ASAS-SN Low Surface Brightness Survey utilizes the $\sim7$ years of g-band CCD data from ASAS-SN (The All-Sky Automated Survey for Supernovae) to create stacked images of the entire sky. It is significantly deeper than previous photographic surveys. Our median/95th percentile cumulative exposure time per field is 58.1/86.8 hours, and our median $3{\sigma}$ g-band surface brightness limit off the Galactic plane ($|b| > 20{\deg}$) is 26.1 mag arcsec$^{-2}$. We image large-scale diffuse structures within the Milky Way, such as multiple degree-spanning supernova remnants and star-forming nebulae, and tidal features of nearby galaxies. To quantify how effective our deep images are, we compare with a catalog of known ultra-diffuse galaxies and find a recovery rate of 82$\%$. In the future, we intend to use this data set to perform an all-sky search for new nearby dwarf galaxies, create an all-sky Galactic cirrus map, create an all-sky low surface brightness mosaic for public use, and more.