Improving Neutrino Point Source Sensitivity with Source-Informed Event Selection

TL;DR

This paper introduces a source-informed event selection method for neutrino telescopes that prioritizes events near known source directions, significantly improving sensitivity with minimal additional computational cost.

Contribution

It proposes a simple modification to event selection that leverages known source locations to enhance neutrino point source detection sensitivity.

Findings

Median point source sensitivity improved by factors of 2-3.

Modest computational overhead of 7-14% for catalogs of about 100 sources.

Method effectively enhances discovery potential without new detector hardware.

Abstract

Neutrino telescopes employ multi-level reconstruction chains, where computationally expensive high-quality reconstructions are applied only to events that survive initial quality cuts based on fast, coarse directional estimates. Currently, event selection between reconstruction levels is source-agnostic, giving no priority to events from directions of known neutrino source candidates. We propose a simple modification to inter-level event selection: preferentially retain events whose early-level reconstruction places them within an angular tolerance of pre-specified candidate source directions from established multi-messenger catalogs, while continuing to subsample remaining events at the baseline rate. Using a realistic two-level detector model with energy-dependent angular resolution, we show that this source-informed selection can improve median point source sensitivity by factors of $\sim 2$--$3$ compared to uniform subsampling, with the improvement depending on the baseline selection efficiency, angular tolerance, and correlation between reconstruction qualities at different levels. For catalogs of $\mathcal{O}(100)$ sources, the additional computational overhead is modest ($\sim 7$--$14\%$). This approach offers a path to substantially enhance the discovery potential of current and future neutrino telescopes without requiring new detector capabilities.