title: Automatic Detection of Gravitational Lenses in Astronomical Image Data
creator: Seidel, Gregor
subject: ddc-520
subject: 520 Astronomy and allied sciences
description: Strong gravitational lensing can magnify distant sources and also provides a direct probe of the mass density between source and observer. For these reasons, it has become an important tool in astronomy. Among other applications, it is used to constrain cosmological parameters, reconstruct the projected mass distribution of galaxy clusters and study their dynamics. Determining the statistical abundance of background galaxies projected into heavily distorted arcs by galaxy cluster lenses could improve our understanding of large scale structure formation, but arc statistics is particularly difficult due to possibly significant biases in the selection of galaxy cluster lenses. In order to provide a larger, unbiased sample of strong lenses, an efficient, automated arc detection software that uses a novel approach to detect elongated structures in images was developed for this PhD thesis. The new detection algorithm is based on locally coherent features and is capable of detecting even faint arcs with high computational efficiency. Postprocessing algorithms were developed to classify the detections and to remove false positives. For calibration and to determine its sensitivity to arcs of different magnitudes the completed software was applied to simulated images. The application to real ACS images resulted in 24 new galaxy-type lens candidates.
date: 2009
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/10088/1/thesis_gseidel.pdf
identifier: DOI:10.11588/heidok.00010088
identifier: urn:nbn:de:bsz:16-opus-100887
identifier:   Seidel, Gregor  (2009) Automatic Detection of Gravitational Lenses in Astronomical Image Data.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/10088/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng