Enabling Early Transient Discovery in LSST via Difference Imaging with DECam

TL;DR

SLIDE is a pipeline that uses archival DECam images for difference imaging to enable early transient discovery in LSST data, effectively identifying new transients and supporting early transient analysis.

Contribution

This paper introduces SLIDE, a novel pipeline that performs difference imaging with archival images to facilitate early transient detection in LSST, especially when templates are incomplete or contaminated.

Findings

Identified 29 new transients, 12 of which were previously undetected.

Demonstrated effective photometry extraction circumventing poor LSST templates.

Showcased the pipeline's utility for early LSST transient analysis.

Abstract

We present SLIDE, a pipeline that enables transient discovery in data from the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST), using archival images from the Dark Energy Camera (DECam) as templates for difference imaging. We apply this pipeline to the recently released Data Preview 1 (DP1; the first public release of Rubin commissioning data) and search for transients in the resulting difference images. The image subtraction, photometry extraction, and transient detection are all performed on the Rubin Science Platform. We demonstrate that SLIDE effectively extracts clean photometry by circumventing poor or missing LSST templates. We identified 29 previously unreported transients, 12 of which would not have been detected based on the DP1 DiaObject catalog. SLIDE will be especially useful for transient analysis in the early years of LSST, when template coverage will be largely incomplete or when templates may be contaminated by transients present at the time of acquisition. We present multiband light curves for a sample of known transients, along with new transient candidates identified through our search. Finally, we discuss the prospects of applying this pipeline during the main LSST survey. Our pipeline is broadly applicable and will support studies of all transients with slowly evolving phases.