Matched Runs Method to Study Extended Regions of Gamma-ray Emission

TL;DR

The paper introduces the Matched Runs Method, a novel background estimation technique for gamma-ray imaging with VERITAS, enabling improved analysis of extended gamma-ray sources.

Contribution

We developed and validated a new background estimation method for analyzing extended gamma-ray sources with VERITAS, overcoming limitations of standard techniques.

Findings

Validated the method on archival VERITAS data.

Demonstrated improved sensitivity for extended sources.

Enabled detailed morphology studies of gamma-ray emission.

Abstract

Imaging atmospheric Cherenkov telescopes, such as the Very Energetic Radiation Imaging Tele-scope Array System (VERITAS), are uniquely suited to resolve the detailed morphology ofextended regions of gamma-ray emission. However, standard VERITAS data analysis techniques have insufficient sensitivity to gamma-ray sources spanning the VERITAS field of view (3.5{\deg}),due to difficulties with background estimation. For analysis of such spatially extended sources with 0.5{\deg} to greater than 2{\deg} radius, we developed the Matched Runs Method. This method derives background estimations for observations of extended sources using matched separate observations of known point sources taken under similar observing conditions. Our technique has been validated by application to archival VERITAS data. Here we present a summary of the Matched RunsMethod and multiple validation studies on different gamma-ray sources using VERITAS data.