85 citations · 165 across the 22 of their papers we have counts for
23 papers
Observing population III stars in the pristine region
Sung Kei Li, Jose M. Diego, Jose M. Palencia
The detection of the long-sought Population III (Pop III) stars is, perhaps, one of the most intriguing missing links in modern astronomy. Caustic crossing events (CCE) -- extreme…
Model independent lensing sub-structure detection with multiply-imaged star clusters constellations
Leo W. H. Fung, Tom Broadhurst, Sung Kei Li +3
A broad class of dark matter (DM) models predicts the existence of sub-structures residing in DM haloes on sub-resolvable angular scales. Techniques to extract such a generic featu…
Extragalactic microlensing through Ultra Diffuse Galaxies
Sung Kei Li, Thomas Broadhurst, Jose M. Diego +4
Stellar microlensing is a powerful method to constrain compact dark matter models, uncover binary stars, and exoplanets during caustic crossing events. At cosmological distances, {…
Massive stars as gravitationally lensed transients -- Insights on the high-mass initial mass function
Sung Kei Li
A robust stellar initial mass function (IMF) is crucial in any studies related to star formation. However, the direct measurement of the stellar IMF is confined to the local univer…
Lensed stars in galaxy-galaxy strong lensing -- a JWST prediction for the Cosmic Horseshoe
Sung Kei Li, Luke Weisenbach, Thomas E. Collett +10
We explore for the first time the possibility of detecting lensed star transients in galaxy-galaxy strong lensing systems upon repeated, deep imaging using the {\it James-Webb Spac…
Magnification bias reveals severe contamination in Hubble Frontier Field photo-z catalogs
Jiashuo Zhang, Jeremy Lim, Tom Broadhurst +4
Gravitational lensing by massive galaxy clusters enables faint distant galaxies to be more abundantly detected than in blank fields, thereby allowing one to construct galaxy lumino…
Signatures of Fuzzy Dark Matter Inside Radial Critical Curves
J. M. Palencia, Paloma Morilla, Sung Kei Li +5
We investigate the strong gravitational lensing properties of fuzzy dark matter (FDM) halos, focusing on the magnification properties near radial critical curves (CCs). Using simul…
Transient star B/R ratio and star formation in lensed galaxies
Sung Kei Li, Jose M. Palencia, Jose M. Diego +8
The extreme magnification from galaxy clusters and microlenses therein allows the detection of individual, luminous stars in lensed galaxies as transient events, and hence provides…
Constraining the z 1 Initial Mass Function with {\it HST} and {\it JWST} Lensed Stars in MACS J0416.1-2403
Sung Kei Li, Jose M. Diego, Ashish K. Meena +19
Our understanding of galaxy properties and evolution is contingent on knowing the initial mass function (IMF), and yet to date, the IMF is constrained only to local galaxies. Indiv…
Flashlights: Prospects for constraining the Initial Mass Function around cosmic noon with caustic-crossing events
Ashish Kumar Meena, Sung Kei Li, Adi Zitrin +7
The Flashlights program with the Hubble Space Telescope imaged the six Hubble Frontier Fields galaxy clusters in two epochs and detected twenty transients. These are primarily expe…
Multi-copy Axion Transfer Function and Observational Implications of Effective de Broglie Scales
Jiashuo Zhang, Tom Broadhurst, Jeremy Lim +2
Ultra-light axions are viable fuzzy/wave-like dark matter (DM) candidates generically predicted by the String Axiverse paradigm with multiple particle copies, whereas most of th…
Are Models of Strong Gravitational Lensing by Clusters Converging or Diverging?
Derek Perera, John H Miller, Liliya L. R. Williams +4
The increasingly large numbers of multiple images in cluster-scale gravitational lenses have allowed for tighter constraints on the mass distributions of these systems. Most lens m…
BUFFALO Wild Wings: A High Precision Free-Form Lens Model of MACSJ0416 with Constraints on Dark Matter from Substructure and Highly Magnified Arcs
Derek Perera, Liliya L. R. Williams, Jori Liesenborgs +10
We present new free-form and hybrid mass reconstructions of the galaxy cluster lens MACS J0416.12403 at using the lens inversion method GRALE. The reconstructions use…
A high-resolution view of the source-plane magnification near cluster caustics in wave dark matter models
Jose M. Diego, Alfred Amruth, Jose M. Palencia +10
We present the highest resolution images to date of caustics formed by wave dark matter (DM) fluctuations near the critical curves of cluster gravitational lenses. We describe t…
Dark Matter distinguished by skewed microlensing in the "Dragon Arc"
Tom Broadhurst, Sung Kei Li, Amruth Alfred +18
Microlensed stars recently discovered by JWST & HST follow closely the winding critical curve of A370 along all sections of the ``Dragon Arc" traversed by the critical curve. These…
Imaging dark matter at the smallest scales with lensed stars
J. M. Diego, Sung Kei Li, Alfred Amruth +19
Observations of caustic-crossing galaxies at redshift show a wealth of transient events. Most of them are believed to be microlensing events of highly magnified stars. Ea…
Flashlights: Transients among Gravitationally-Lensed Star Clusters in the Dragon Arc. I. Stellar Microlensing vs Stellar Outbursts
Sung Kei Li, Jose M. Diego, Patrick L. Kelly +8
We report the discovery of transients among star clusters in a distant galaxy that is gravitationally lensed by a foreground galaxy cluster, and explore whether these transients co…
A Lens Finder Map to check claimed High-z Galaxies behind SMACS J0723.3-7327
Alex Chow, Sung Kei Li, Tom Broadhurst +5
The first science image released by the JWST reveals numerous galaxies in the distant background of the galaxy cluster SMACS J0723.3-7327. Some have claimed redshifts of up to $z \…
BUFFALO/Flashlights: Constraints on the abundance of lensed supergiant stars in the Spock galaxy at redshift 1
Jose M. Diego, Sung Kei Li, Ashish K. Meena +27
We present a constraint on the abundance of supergiant (SG) stars at redshift z approx. 1, based on recent observations of a strongly lensed arc at this redshift. First we derive a…
Einstein rings modulated by wavelike dark matter from anomalies in gravitationally lensed images
Alfred Amruth, Tom Broadhurst, Jeremy Lim +10
Unveiling the true nature of Dark Matter (DM), which manifests itself only through gravity, is one of the principal quests in physics. Leading candidates for DM are weakly interact…
Flashlights: Properties of Highly Magnified Images Near Cluster Critical Curves in the Presence of Dark Matter Subhalos
Liliya L. R. Williams, Patrick L. Kelly, Tommaso Treu +7
Dark matter subhalos with extended profiles and density cores, and globular stars clusters of mass , that live near the critical curves in galaxy cluster lenses…
Flashlights: More than A Dozen High-Significance Microlensing Events of Extremely Magnified Stars in Galaxies at Redshifts z=0.7-1.5
Patrick L. Kelly, Wenlei Chen, Amruth Alfred +23
Once only accessible in nearby galaxies, we can now study individual stars across much of the observable universe aided by galaxy-cluster gravitational lenses. When a star, compact…
Flashlights: An Off-Caustic Lensed Star at Redshift = 1.26 in Abell 370
Ashish Kumar Meena, Wenlei Chen, Adi Zitrin +10
We report the discovery of a transient seen in a strongly lensed arc at redshift in \emph{Hubble Space Telescope} imaging of the Abell 370 galaxy cluster. The tr…