Statistics of magnification for extremely lensed high redshift stars

Abstract

Microlensing of stars in strongly lensed galaxies can lead to temporary extreme magnification factors ($\mu >1000$), enabling their detection at high redshifts. Following the discovery of Icarus, several stars at cosmological distances ($z>1$) have been observed using the Hubble Space Telescope (HST) and the James Webb Space Telescope (JWST). This emerging field of gravitational lensing holds promise to study individual high redshift stars. Also offers the opportunity to study the substructure in the lens plane with implications for dark matter models, as more lensed stars are detected and analysed statistically. Due to the computational demands of simulating microlensing at large magnification factors, it is important to develop fast and accurate analytical approximations for the probability of magnification in such extreme scenarios. In this study, we consider different macro-model magnification and microlensing surface mass density scenarios and study how the probability of extreme magnification factors depends on these factors. To achieve this, we create state of the art large simulations of the microlensing effect in these scenarios. Through the analysis of these simulations, we derive analytical scaling relationships that can bypass the need for expensive numerical simulations. Our results are useful to interpret current observations of stars at cosmic distances which are extremely magnified and under the influence of microlenses.

24 pages, 29 figures

References in corpus (15)

• Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds
• Constraints on Earth-mass primordial black holes from OGLE 5-year microlensing events
• Understanding caustic crossings in giant arcs: characteristic scales, event rates, and constraints on compact dark matter
• JWST's PEARLS: Prime Extragalactic Areas for Reionization and Lensing Science: Project Overview and First Results
• A Highly Magnified Star at Redshift 6.2
• Do Evaporating Black Holes Form Photospheres?
• Limits on the Mass and Abundance of Primordial Black Holes from Quasar Gravitational Microlensing
• Microlensing of Extremely Magnified Stars near Caustics of Galaxy Clusters
• JWST Imaging of Earendel, the Extremely Magnified Star at Redshift $z=6.2$
• Two lensed star candidates at $z\simeq 4.8$ behind the galaxy cluster MACS J0647.7+7015
• JWST's PEARLS: a new lens model for ACT-CL J0102$-$4915, "EL Gordo'', and the first red supergiant star at cosmological distances discovered by JWST
• Early results from GLASS-JWST VIII: An Extremely Magnified Blue Supergiant Star at Redshift 2.65 in the Abell 2744 Cluster Field
• An Efficient Method for Simulating Light Curves of Cosmological Microlensing and Caustic Crossing Events
• Flashlights: An Off-Caustic Lensed Star at Redshift $z$ = 1.26 in Abell 370
• Detecting compact dark matter in galaxy clusters via gravitational microlensing: A2218 & A370

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• A high-resolution view of the source-plane magnification near cluster caustics in wave dark matter models
• Caustic crossings in giant arcs with extended dark matter objects
• Transient star B/R ratio and star formation in $z\gtrsim 1$ lensed galaxies
• Across the Universe: GW231123 as a magnified and diffracted black hole merger
• Extending the cosmic distance ladder two orders of magnitude with strongly lensed Cepheids, carbon AGB, and RGB stars
• Lensed stars in galaxy-galaxy strong lensing -- a JWST prediction for the Cosmic Horseshoe
• Kinematic Mapping of Giant Arcs: A New Method to Locate Lensing Critical Curves