The Large Synoptic Survey Telescope as a Near-Earth Object Discovery Machine

TL;DR

This paper evaluates LSST's capability to discover Near-Earth Objects and Potentially Hazardous Asteroids, demonstrating that strategic survey extensions can significantly improve detection rates and reduce undiscovered hazardous objects.

Contribution

It provides an empirical assessment of LSST's NEO detection potential and explores survey modifications to enhance discovery yields.

Findings

LSST can detect approximately 66% of PHAs brighter than H=22 with its baseline strategy.

Extending the survey by two years and increasing the search window raises PHA detection to 86%.

False detection rate in LSST image differencing is about 450 deg$^{-2}$.

Abstract

Using the most recent prototypes, design, and as-built system information, we test and quantify the capability of the Large Synoptic Survey Telescope (LSST) to discover Potentially Hazardous Asteroids (PHAs) and Near-Earth Objects (NEOs). We empirically estimate an expected upper limit to the false detection rate in LSST image differencing, using measurements on DECam data and prototype LSST software and find it to be about $450$~deg$^{-2}$. We show that this rate is already tractable with current prototype of the LSST Moving Object Processing System (MOPS) by processing a 30-day simulation consistent with measured false detection rates. We proceed to evaluate the performance of the LSST baseline survey strategy for PHAs and NEOs using a high-fidelity simulated survey pointing history. We find that LSST alone, using its baseline survey strategy, will detect $66\%$ of the PHA and $61\%$ of the NEO population objects brighter than $H=22$, with the uncertainty in the estimate of $\pm5$ percentage points. By generating and examining variations on the baseline survey strategy, we show it is possible to further improve the discovery yields. In particular, we find that extending the LSST survey by two additional years and doubling the MOPS search window increases the completeness for PHAs to $86\%$ (including those discovered by contemporaneous surveys) without jeopardizing other LSST science goals ($77\%$ for NEOs). This equates to reducing the undiscovered population of PHAs by additional $26\%$ ($15\%$ for NEOs), relative to the baseline survey.