Morphometric analysis in gamma-ray astronomy using Minkowski functionals - Source detection via structure quantification

TL;DR

This paper introduces a novel morphometric analysis method using Minkowski functionals to detect faint extended gamma-ray sources in sky maps, enhancing traditional count-based techniques by incorporating geometric structure information.

Contribution

The paper develops and applies a new structure-based analysis technique using Minkowski functionals for gamma-ray source detection, improving sensitivity to extended sources without prior source knowledge.

Findings

Successfully applied to H.E.S.S. data

Enhanced detection of faint extended sources

Incorporates geometric structure information

Abstract

Aims. H.E.S.S. observes an increasing number of large extended sources. A new technique based on the structure of the sky map is developed to account for these additional structures by comparing them with the common point source analysis. Methods. Minkowski functionals are powerful measures from integral geometry. They can be used to quantify the structure of the counts map, which is then compared with the expected structure of a pure Poisson background. Gamma-ray sources lead to significant deviations from the expected background structure. The standard likelihood ratio method is exclusively based on the number of excess counts and discards all further structure information of large extended sources. The morphometric data analysis incorporates this additional geometric information in an unbiased analysis, i.e., without the need of any prior knowledge about the source. Results. We have successfully applied our method to data of the H.E.S.S. experiment. The morphometric analysis presented here is dedicated to detecting faint extended sources.