Extrapolating the projected potential of gravitational lens models: property-preserving degeneracies

Fuente: arXiv
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Auteurs principaux: Liesenborgs, Jori, Perera, Derek, Williams, Liliya L. R.
Format: Preprint
Publié: 2024
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author Liesenborgs, Jori
Perera, Derek
Williams, Liliya L. R.
author_facet Liesenborgs, Jori
Perera, Derek
Williams, Liliya L. R.
contents While gravitational lens inversion holds great promise to reveal the structure of the light-deflecting mass distribution, both light and dark, the existence of various kinds of degeneracies implies that care must be taken when interpreting the resulting lens models. This article illustrates how thinking in terms of the projected potential helps to gain insight into these matters. Additionally it is shown explicitly how, when starting from a discretised version of the projected potential of one particular lens model, the technique of quadratic programming can be used to create a multitude of equivalent lens models that preserve all or a subset of lens properties. This method is applied to a number of scenarios, showing the lack of grasp on the mass outside the strong lensing region, revisiting mass redistribution in between images and applying this to a recent model of the SDSS J1004+4112 cluster, as well as illustrating the generalised mass sheet degeneracy and source-position transformation. In the case of J1004 we show that this mass redistribution did not succeed at completely eliminating a dark mass clump recovered by GRALE near one of the quasar images.
format Preprint
id arxiv_https___arxiv_org_abs_2402_17591
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Extrapolating the projected potential of gravitational lens models: property-preserving degeneracies
Liesenborgs, Jori
Perera, Derek
Williams, Liliya L. R.
Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
While gravitational lens inversion holds great promise to reveal the structure of the light-deflecting mass distribution, both light and dark, the existence of various kinds of degeneracies implies that care must be taken when interpreting the resulting lens models. This article illustrates how thinking in terms of the projected potential helps to gain insight into these matters. Additionally it is shown explicitly how, when starting from a discretised version of the projected potential of one particular lens model, the technique of quadratic programming can be used to create a multitude of equivalent lens models that preserve all or a subset of lens properties. This method is applied to a number of scenarios, showing the lack of grasp on the mass outside the strong lensing region, revisiting mass redistribution in between images and applying this to a recent model of the SDSS J1004+4112 cluster, as well as illustrating the generalised mass sheet degeneracy and source-position transformation. In the case of J1004 we show that this mass redistribution did not succeed at completely eliminating a dark mass clump recovered by GRALE near one of the quasar images.
title Extrapolating the projected potential of gravitational lens models: property-preserving degeneracies
topic Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2402.17591