Identification and photometric classification of extragalactic transients in the Vera C. Rubin Observatory's Data Preview 1

TL;DR

This paper demonstrates the potential of the Vera C. Rubin Observatory's Data Preview 1 for detecting and classifying extragalactic transients, particularly supernovae, using photometric methods in early survey data.

Contribution

It introduces a method for identifying and classifying extragalactic transients in early LSST data, showing promising detection rates and classification confidence.

Findings

Identified 8 new likely supernovae and 3 known ones in early survey data.

Photometric classification achieved >95% confidence for select supernovae.

Detection rate aligns with simulation predictions, validating early data quality.

Abstract

The Vera C. Rubin Observatory will soon survey the southern sky, delivering a depth and sky coverage that is unprecedented in time domain astronomy. As part of commissioning, Data Preview 1 (DP1) has been released. It comprises a LSSTComCam observing campaign between November and December 2024 with multi-band imaging of seven fields, covering roughly 0.4 square degrees each, providing a first glimpse into the data products that will become available once the Legacy Survey of Space and Time begins. In this work, we search three fields for extragalactic transients. We identify eight new likely supernovae, and three known ones from a sample of 369,644 difference image analysis objects. Photometric classification using Superphot+ assigns sub-classes with >95% confidence to only one SN Ia and one SN II in this sample. Our findings are in agreement with supernova detection rate predictions of $15\pm4$ supernovae from simulations using simsurvey. The supernova detection rate in the data is possibly affected by the lack of suitable templates. Nevertheless, this work demonstrates the quality of the data products delivered in DP1 and indicates that the Rubin Observatory's Legacy Survey of Space and Time (LSST) is well placed to fulfill its discovery potential in time domain astronomy.