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Title: Flashlights: Properties of Highly Magnified Images Near Cluster Critical Curves in the Presence of Dark Matter Subhalos
Abstract

Dark matter subhalos with extended profiles and density cores, and globular star clusters of mass 106–108Mthat live near the critical curves in galaxy cluster lenses can potentially be detected through their lensing magnification of stars in background galaxies. In this work, we study the effect such subhalos have on lensed images, and compare to the case of more well-studied microlensing by stars and black holes near critical curves. We find that the cluster density gradient and the extended mass distribution of subhalos are important in determining image properties. Both lead to an asymmetry between the image properties on the positive- and negative-parity sides of the cluster that is more pronounced than in the case of microlensing. For example, on the negative-parity side, subhalos with cores larger than about 50 pc do not generate any images with magnification above ∼100 outside of the immediate vicinity of the cluster critical curve. We discuss these factors using analytical and numerical analysis, and exploit them to identify observable signatures of subhalos: Subhalos create pixel-to-pixel flux variations of ≳0.1 mag on the positive-parity side of clusters. These pixels tend to cluster around (otherwise invisible) subhalos. Unlike in the case of microlensing, signatures of subhalo lensing can be found up to 1″ away from the critical curves of massive clusters.

 
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Award ID(s):
1908823
NSF-PAR ID:
10487759
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ;
Publisher / Repository:
DOI PREFIX: 10.3847
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
961
Issue:
2
ISSN:
0004-637X
Format(s):
Medium: X Size: Article No. 200
Size(s):
["Article No. 200"]
Sponsoring Org:
National Science Foundation
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