Morphometric analysis in gamma-ray astronomy using Minkowski functionals
Source detection via structure quantification
Erlangen Centre for Astroparticle Physics, Universität
e-mail: email@example.com; firstname.lastname@example.org
2 Institut für Theoretische Physik, Universität Erlangen-Nürnberg, Staudtstr. 7, 91058 Erlangen, Germany
3 DESY, Platanenallee 6, 15738 Zeuthen, Germany
Received: 21 January 2013
Accepted: 18 April 2013
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.
Key words: methods: data analysis / methods: statistical / techniques: image processing / gamma rays: diffuse background
© ESO, 2013