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Gravitational lensing with stochastic substructure: Effects of the clump mass function and spatial distribution

Keeton, Charles R. (2009) Gravitational lensing with stochastic substructure: Effects of the clump mass function and spatial distribution. . http://resolver.caltech.edu/CaltechAUTHORS:20160218-144152809

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Abstract

Mass clumps in gravitational lens galaxies can perturb lensed images in characteristic ways. Strong lens flux ratios have been used to constrain the amount of dark matter substructure in lens galaxies, and various other observables have been considered as additional probes of substructure. We study the general theory of lensing with stochastic substructure in order to understand how lensing observables depend on the mass function and spatial distribution of clumps. We find that magnification perturbations are mainly sensitive to the total mass in substructure projected near the lensed images; when the source is small, flux ratios are not very sensitive to the shape of the clump mass function. Position perturbations are mainly sensitive to a characteristic clump mass scale, namely m_eff = <m^2>/<m>, with some mild dependence on other mass moments when the spatial distribution is not uniform. They have contributions from both "local" and "global" populations of clumps (i.e., those projected near the images, and those farther away). Time delay perturbations are sensitive to the same characteristic mass, m_eff, and mainly driven by the global population of clumps. While there is significant scatter in all lensing quantities, there are some non-trivial correlations that may contain further information about the clump population. Our results indicate that a joint analysis of multiple lens observables will offer qualitatively new constraints on the mass function and spatial distribution of dark matter substructure in distant galaxies.


Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription
http://arxiv.org/abs/0908.3001arXivDiscussion Paper
Additional Information:Submitted 20 Aug 2009. I thank Jacqueline Chen, Art Congdon, Greg Dobler, Ross Fadely, Mike Kuhlen, Leonidas Moustakas, Joel Primack, Eduardo Rozo, Kris Sigurdson, and Risa Wechsler for helpful discussions about astrophysical aspects of dark matter, substructure, and lensing; as well as Arlie Petters, Alberto Teguia, and Kelly Wieand for productive conversations about mathematical aspects of stochastic lensing. Ross Fadely also provided helpful comments on the manuscript. I thank the astrophysics group at the Institute for Advanced Study and the organisers and participants of the workshops “Strong Gravitational Lensing in the Next Decade” and “Shedding Light on the Nature of Dark Matter” for opportunities to present preliminary versions of this work. Principal support for this work has come from NSF through grant AST-0747311, with additional support from the Institute for Advanced Study and the W. M. Keck Institute for Space Studies.
Group:Keck Institute for Space Studies
Funders:
Funding AgencyGrant Number
Institute for Advanced StudyUNSPECIFIED
Keck Institute for Space Studies (KISS)UNSPECIFIED
NSFAST-0747311
DOI:10.26206/GTYK-TJ83
Record Number:CaltechAUTHORS:20160218-144152809
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160218-144152809
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:64589
Collection:CaltechAUTHORS
Deposited By: Colette Connor
Deposited On:20 Feb 2016 00:55
Last Modified:21 Mar 2019 21:15

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