New Photometric Pipeline to Explore Temporal and Spatial Variability with KMTNet DEEP-South Observations

TL;DR

This paper introduces a new photometric pipeline utilizing multi-aperture photometry and FastBit indexing to efficiently analyze large time-series data from KMTNet DEEP-South observations, leading to the discovery of new variable stars and recovery of asteroid data.

Contribution

The paper presents a novel automated pipeline for high-precision photometry and variability detection in large datasets, enhancing the exploration of temporal and spatial variability in small Solar System bodies.

Findings

Discovered 21 new periodic variable stars, including eclipsing binaries and rotating variables.

Recovered astrometry and photometry of two near-earth asteroids with high accuracy.

Demonstrated the pipeline's effectiveness in identifying variable phenomena in massive datasets.

Abstract

The DEEP-South photometric census of small Solar System bodies produces massive time-series data of variable, transient or moving objects as a by-product. To fully investigate unexplored variable phenomena, we present an application of multi-aperture photometry and FastBit indexing techniques for faster access to a portion of the DEEP-South year-one data. Our new pipeline is designed to perform automated point source detection, robust high-precision photometry and calibration of non-crowded fields which have overlap with previously surveyed areas. In this paper, we show some examples of catalog-based variability searches to find new variable stars and to recover targeted asteroids. We discover 21 new periodic variables with period ranging between 0.1 and 31 days, including four eclipsing binary systems (detached, over-contact, and ellipsoidal variables), one white dwarf/M dwarf pair candidate, and rotating variable stars. We also recover astrometry ($<\pm$1--2 arcsec level accuracy) and photometry of two targeted near-earth asteroids, 2006 DZ169 and 1996 SK, along with the small- ($\sim$0.12 mag) and relatively large-amplitude ($\sim$0.5 mag) variations of their dominant rotational signals in $R$-band.