Karlsruhe 2024 – scientific programme
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T: Fachverband Teilchenphysik
T 10: Gamma astronomy 1
T 10.1: Talk
Monday, March 4, 2024, 16:00–16:15, Geb. 30.22: kl. HS A
Background estimation for IACTs combining a run matching approach with a background template — •Tina Wach1, Alison Mitchell1, and Lars Mohrmann2 — 1Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander-Universität Erlangen-Nürnberg — 2Max-Planck-Institut für Kernphysik
Detecting large, extended gamma-ray structures using IACTs has been a major challenge due to their comparatively small field-of-view. In the case of large extended sources, the separation between background and source signal is challenging, since most techniques rely on the background signal evaluation from source-free regions within the field-of-view of the respective observation. This is however only possible if the gamma-ray emission is well contained within the field-of-view of the telescope array. One way to overcome this challenge is to estimate the background from a separate observation of a source-free region, although this can introduce large systematic uncertainties.
To decrease the systematic uncertainties and their correlation to the choice of the observation of the source-free region, we use the open-source tool gammapy to combine the ON observation / OFF observation method with a 3-dimensional background template, created from a large amount of archival data of the H.E.S.S. array. We then use data from the first public data release of the H.E.S.S. Collaboration to validate the technique and evaluate the systematic errors introduced. We show that this method is a stable approach to estimate the background rate in complicated regions of the sky where other approaches cannot be used.
Keywords: IACT; background; open source tools