Uncovering the Next Galactic Supernova with the Vera C. Rubin Observatory

TL;DR

The paper investigates how the Vera C. Rubin Observatory can identify the electromagnetic counterpart of the next galactic core-collapse supernova triggered by neutrino alerts. It combines a Milky Way CCSN candidate catalog from LSST TRILEGAL, light curves from SCOTCH, and SFD dust extinction to predict Rubin-band detectability and SBO brightness, using 30 s exposures. A key finding is that Rubin is well-positioned to provide initial localization for most observable events, with a 57–97% success range depending on assumptions, and SBO detection is feasible in redder bands. The authors propose an actionable, rapid-follow-up observing strategy to maximize SBO capture while acknowledging practical challenges such as sky coverage, crowded fields, and detector trip-off risks in bright events.

Abstract

Supernovae are observed to occur approximately 1-2 times per century in a galaxy like the Milky Way. Based on historical records, however, the last core-collapse galactic supernova observed by humans occurred almost 1,000 years ago. Luckily, we are well positioned to catch the next one with the advent of new neutrino detectors and astronomical observatories. Neutrino observatories can provide unprecedented triggers for a galactic supernova event as they are likely to see a supernova neutrino signal anywhere from minutes to days before the shock breakout causes the supernova to brighten in optical wavelengths. Given its large etendue, the Vera C. Rubin Observatory is ideally positioned to rapidly localize the optical counterpart based on the neutrino trigger. In this paper we simulate events to study the efficiency with which supernovae are optimally localized by the Vera C. Rubin Observatory. We find that the observatory is ideal for initial localization of nearly all observable supernova triggers and has a 57-97% chance of catching any supernova based on theoretical stellar mass density predictions and observations. We provide an analysis of optimal filter selection and exposure times and discuss observational caveats.

Figures (9)

• Figure 1: Top: Probability distribution of the distance away from Earth for the TRILEGAL CCSN candidates. Bottom: Same as the panel above as a cumulative distribution.
• Figure 2: Top: The distribution of TRILEGAL stars in a Molleview Celestial projection. Bottom: Same as the above figure but in galactic coordinates. Both of these show the visibility cutoff due to the location of Rubin.
• Figure 3: Probability distribution of events and their corresponding peak absolute LSST r-band magnitude for Type II CCSN SCOTCH Models. For our study, we focused on the SN-II Template model.
• Figure 4: The probability distribution of the peak (solid) and SBO (dashed) apparent magnitudes for all LSST TRILEGAL CCSN candidates with CCSN rates applied, using the SCOTCH SN-II and SN-Ib Template models used to represent Type-II and Type-I, respectively.
• Figure 5: Cumulative distribution of values shown in Figure \ref{['fig:PDF']}. The Rubin magnitude depth limits and saturation limits of a 30 second exposure at an airmass of 1 are shown in solid and dashed lines, respectively. The black dashed line represents the magnitude of a CCSN that could trip off a detector. To match this to the numbers in Table \ref{['tab:Sat_sig']}, the intersection of the 'Saturation' line and the curve corresponds to the 'Saturated' column, the difference between the $5\sigma$ exposure depth intersection and the saturation intersection corresponds to the 'Visible' column, and the 'Too Faint' column is 1 minus the $5\sigma$ intersection.