Microlensing Near Macro-Caustics
Name
11214_2024_Article_1088.pdf
Size
1.31 MB
Format
Adobe PDF
Checksum (MD5)
a32eeef53edc9f02214b42cb45b9958c
Author(s)
Weisenbach, Luke
Anguita, Timo
Miralda-Escudé, Jordi
Oguri, Masamune
Saha, Prasenjit
Schechter, Paul L.
Date Issued
July 30, 2024
Journal
Space Science Reviews
Publisher
Springer Netherlands
Citation
Weisenbach, L., Anguita, T., Miralda-Escudé, J. et al. Microlensing Near Macro-Caustics. Space Sci Rev 220, 57 (2024).
Version
Final published version
Abstract
Microlensing near macro-caustics is a complex phenomenon in which swarms of micro-images produced by micro-caustics form on both sides of a macro-critical curve. Recent discoveries of highly magnified images of individual stars in massive galaxy cluster lenses, predicted to be formed by these micro-image swarms, have stimulated studies on this topic. In this article, we explore microlensing near macro-caustics using both simulations and analytic calculations. We show that the mean total magnification of the micro-image swarms follows that of an extended source in the absence of microlensing. Micro-caustics join into a connected network in a region around the macro-critical line of a width proportional to the surface density of microlenses; within this region, the increase of the mean magnification toward the macro-caustic is driven by the increase of the number of micro-images rather than individual magnifications of micro-images. The maximum achievable magnification in micro-caustic crossings decreases with the mass fraction in microlenses. We conclude with a review of applications of this microlensing phenomenon, including limits to the fraction of dark matter in compact objects, and searches of Population III stars and dark matter subhalos. We argue that the discovered highly magnified stars at cosmological distances already imply that less than ∼ 10% of the dark matter may be in the form of compact objects with mass above ∼10−6 𝑀⊙.
MIT Department
MIT Kavli Institute for Astrophysics and Space Research
Terms of Use
Creative Commons Attribution
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1007/s11214-024-01088-9
