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Main Authors: Zhou, Qing, Sonnenfeld, Alessandro, Hoekstra, Henk
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2406.17019
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author Zhou, Qing
Sonnenfeld, Alessandro
Hoekstra, Henk
author_facet Zhou, Qing
Sonnenfeld, Alessandro
Hoekstra, Henk
contents The statistics of Einstein radii for a sample of strong lenses can provide valuable constraints on the underlying mass distribution. The correct interpretation, however, relies critically on the modelling of the selection of the sample, which has proven to be a limiting factor. This may change thanks to upcoming uniform high-resolution imaging surveys that cover a large fraction of the sky, because they can provide complete lens samples, with well understood selection criteria. To explore how the observed distribution of Einstein radii depends on the galaxy properties, we simulated a realistic complete sample of strong lenses, predicting a number density of lenses of about 2.5 deg$^{-2}$ for a \Euclid-like setup. Such data can break the degeneracy between the stellar initial mass function (IMF) and the inner slope of the density profile of dark matter, without having to rely on additional information from stellar dynamics. We found that a survey covering only 50 deg$^2$ can already provide tight constraints: assuming that the cosmology is known, the dark matter slope is recovered with an uncertainty of $3.5\%$, while the uncertainty in the ratio between the true stellar mass and that inferred from stellar population modelling was found to be $10\%$. These findings highlight the potential of this method when applied to samples of lenses with well-understood selection functions.
format Preprint
id arxiv_https___arxiv_org_abs_2406_17019
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Constraining galaxy properties with complete samples of lenses
Zhou, Qing
Sonnenfeld, Alessandro
Hoekstra, Henk
Cosmology and Nongalactic Astrophysics
The statistics of Einstein radii for a sample of strong lenses can provide valuable constraints on the underlying mass distribution. The correct interpretation, however, relies critically on the modelling of the selection of the sample, which has proven to be a limiting factor. This may change thanks to upcoming uniform high-resolution imaging surveys that cover a large fraction of the sky, because they can provide complete lens samples, with well understood selection criteria. To explore how the observed distribution of Einstein radii depends on the galaxy properties, we simulated a realistic complete sample of strong lenses, predicting a number density of lenses of about 2.5 deg$^{-2}$ for a \Euclid-like setup. Such data can break the degeneracy between the stellar initial mass function (IMF) and the inner slope of the density profile of dark matter, without having to rely on additional information from stellar dynamics. We found that a survey covering only 50 deg$^2$ can already provide tight constraints: assuming that the cosmology is known, the dark matter slope is recovered with an uncertainty of $3.5\%$, while the uncertainty in the ratio between the true stellar mass and that inferred from stellar population modelling was found to be $10\%$. These findings highlight the potential of this method when applied to samples of lenses with well-understood selection functions.
title Constraining galaxy properties with complete samples of lenses
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2406.17019