Finding the Fuse: Prospects for the Detection and Characterization of Hydrogen-Rich Core-Collapse Supernova Precursor Emission with the LSST

TL;DR

This paper forecasts the detection prospects of hydrogen-rich precursor emissions before core-collapse supernovae using LSST data, highlighting the potential discovery rates and strategies for identifying these phenomena.

Contribution

It simulates precursor models and predicts detection rates in LSST data, providing strategies to improve identification of pre-supernova emissions.

Findings

Detection rate of 40-130 per year for SN IIP/IIL precursors in single-epoch photometry.

Detection rate of approximately 110 per year for SN IIn precursors.

Total predicted detections of 150-400 over three years with binned photometry.

Abstract

Enhanced emission in the months to years preceding explosion has been detected for several core-collapse supernovae (SNe). Though the physical mechanisms driving the emission remain hotly debated, the light curves of detected events show long-lived ($\geq$50 days), plateau-like behavior, suggesting hydrogen recombination may significantly contribute to the total energy budget. The Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) will provide a decade-long photometric baseline to search for this emission, both in binned pre-explosion observations after an SN is detected and in single-visit observations prior to the SN explosion. In anticipation of these searches, we simulate a range of eruptive precursor models to core-collapse SNe and forecast the discovery rates of these phenomena in LSST data. We find a detection rate of ~40-130 yr$^{-1}$ for SN IIP/IIL precursors and ~110 yr$^{-1}$ for SN IIn precursors in single-epoch photometry. Considering the first three years of observations with the effects of rolling and observing triplets included, this number grows to a total of 150-400 in binned photometry, with the highest number recovered when binning in 100-day bins for 2020tlf-like precursors and in 20-day bins for other recombination-driven models from the literature. We quantify the impact of using templates contaminated by residual light (from either long-lived or separate precursor emission) on these detection rates, and explore strategies for estimating baseline flux to mitigate these issues. Spectroscopic follow-up of the eruptions preceding core-collapse SNe and detected with LSST will offer important clues to the underlying drivers of terminal-stage mass loss in massive stars.