Scientific Verification of the High Altitude Water Cherenkov observatory

TL;DR

This paper reports on the verification process of the HAWC observatory's data acquisition and event reconstruction algorithms through comparison of Monte Carlo simulations with real data collected during initial commissioning.

Contribution

It provides the first comparison between Monte Carlo simulations and actual data from the HAWC observatory during early commissioning phases.

Findings

Good agreement between simulation and data validates the data analysis methods.

Verification of detector performance across different configurations.

Confirmation of the observatory's readiness for scientific observations.

Abstract

The High Altitude Water Cherenkov (HAWC) observatory is a TeV gamma-ray and cosmic-ray detector currently under construction at an altitude of 4100 m close to volcano Sierra Negra in the state of Puebla, Mexico. The HAWC observatory is an extensive air-shower array comprised of 300 optically-isolated water Cherenkov detectors (WCDs). Each WCD contains $\sim$200,000 liters of filtered water and four upward-facing photomultiplier tubes. In Fall 2014, when the HAWC observatory will reach an area of 22,000 m$^{2}$, the sensitivity will be 15 times higher than its predecessor Milagro. Since September 2012, more than 30 WCDs have been instrumented and taking data. This first commissioning phase has been crucial for the verification of the data acquisition and event reconstruction algorithms. Moreover, with the increasing number of instrumented WCDs, it is important to verify the data taken with different configuration geometries. In this work we present a comparison between Monte Carlo simulation and data recorded by the experiment during 24 hours of live time between 14 and 15 April of 2013 when 29 WCDs were active.