Publications by Hung-Hsu Chan | EPFL Graph Search

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Context. Strong lenses are extremely useful probes of the distribution of matter on galaxy and cluster scales at cosmological distances, however, they are rare and difficult to find. The number of currently known lenses is on the order of 1000.Aims. The ai ...

We report periodic oscillations in the 15-year-long optical light curve of the gravitationally lensed quasar Q J0158-4325 at z(s) = 1.29. The signal is enhanced during a high magnification microlensing event of the quasar that the fainter lensed image, B, ...

We investigate strongly gravitationally lensed type II supernovae (LSNe II) for time-delay cosmography, incorporating microlensing effects; this expands on previous microlensing studies of type Ia supernovae (SNe Ia). We use the radiative-transfer code TAR ...

The microlensing signal in the light curves of gravitationally lensed quasars can shed light on the dark matter (DM) composition in their lensing galaxies. Here, we investigate a sample of six lensed quasars from the most recent and best COSMOGRAIL observa ...

Extremely light bosonic wave dark matter (y/DM) is an emerging dark matter candidate contesting the conventional cold dark matter paradigm and a model subject to intense scrutiny of late. This work for the first time reports testable salient features perti ...

High-redshift binary quasars provide key insights into mergers and quasar activity, and are useful tools for probing the spatial kinematics and chemistry of galaxies along the line of sight. However, only three sub-10-kpc binaries have been confirmed above ...

We present our search for strong lens, galaxy-scale systems in the first data release of the Dark Energy Survey (DES), based on a color-selected parent sample of 18 745 029 luminous red galaxies (LRGs). We used a convolutional neural network (CNN) to grade ...

Context. The determination of the stellar initial mass function (IMF) of massive galaxies is one of the open problems in cosmology. Strong gravitational lensing is one of the few methods that allow us to constrain the IMF outside of the Local Group. Aims. ...

We conduct a search for galaxy-scale strong gravitational lens systems in Data Release 4 of the Hyper Suprime-Cam Subaru Strategic Program (HSC SSP), consisting of data taken up to the S21A semester. We select 103191 luminous red galaxies from the Baryon O ...

To use strongly lensed Type Ia supernovae (LSNe Ia) for cosmology, a time-delay measurement between the multiple supernova (SN) images is necessary. The sharp rise and decline of SN Ia light curves make them promising for measuring time delays, but microle ...

Gravitational microlensing is a powerful tool for probing the inner structure of strongly lensed quasars and for constraining parameters of the stellar mass function of lens galaxies. This is achieved by analysing microlensing light curves between the mult ...

Boson stars are gravitationally bound objects that arise in ultralight dark matter models and form in the centers of galactic halos or axion miniclusters. We systematically study the excitations of a boson star, taking into account the mixing between posit ...

Axion-like particles, including the QCD axion, are well-motivated dark matter candidates. Numerical simulations have revealed coherent soliton configurations, also known as boson stars, in the centers of axion halos. We study evolution of axion solitons im ...

The Hubble constant (H-0) is one of the fundamental parameters in cosmology, but there is a heated debate around the > 4 sigma tension between the local Cepheid distance ladder and the early Universe measurements. Strongly lensed Type Ia supernovae (LSNe I ...

We present a search for galaxy-scale strong gravitational lenses in the initial 2500 square degrees of the Canada-France Imaging Survey (CFIS). We designed a convolutional neural network (CNN) committee that we applied to a selection of 2 344 002 r-band im ...

Gravitationally lensed quasars are useful for studying astrophysics and cosmology, and enlarging the sample size of lensed quasars is important for multiple studies. In this work, we develop a lens search algorithm for four-image (quad) lensed quasars base ...

We investigate the ability of human 'expert' classifiers to identify strong gravitational lens candidates in Dark Energy Survey like imaging. We recruited a total of 55 people that completed more than 25 per cent of the project. During the classification t ...

We present the discovery of a gravitationally lensed dust-reddened QSO at z = 2.517, identified in a survey for QSOs by infrared selection. Hubble Space Telescope imaging reveals a quadruply lensed system in a cusp configuration, with a maximum image separ ...

We present a lensed quasar search based on the variability of lens systems in the Hyper Suprime-Cam (HSC) transient survey. Starting from 101 353 variable objects with i-band photometry in the HSC transient survey, we used a variability-based lens search m ...

We present spectroscopic confirmation of three new two-image gravitationally lensed quasars, compiled from existing strong lens and X-ray catalogues. Images of HSC J091843.27-022007.5 show a red galaxy with two blue point sources at either side, separated ...

Hung-Hsu Chan

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Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI): VI. Crowdsourced lens finding with Space Warps

Evidence for a milliparsec-separation supermassive binary black hole with quasar microlensing

HOLISMOKES V. Microlensing of type II supernovae and time-delay inference through spectroscopic phase retrieval

Probing compact dark matter objects with microlensing in gravitationally lensed quasars

Multiple Images and Flux Ratio Anomaly of Fuzzy Gravitational Lenses

J1721+8842: a gravitationally lensed binary quasar with a proximate damped Lyman-alpha absorber

Search of strong lens systems in the Dark Energy Survey using convolutional neural networks

Survey of gravitationally-lensed objects in HSC imaging (SuGOHI) III. Statistical strong lensing constraints on the stellar IMF of CMASS galaxies

Survey of Gravitationally lensed objects in HSC Imaging (SuGOHI). VIII. New galaxy-scale lenses from the HSC SSP

HOLISMOKES: III. Achromatic phase of strongly lensed Type Ia supernovae

Constraining quasar structure using high-frequency microlensing variations and continuum reverberation

Boson star normal modes

Condensation and evaporation of boson stars

HOLISMOKES VII. Time-delay measurement of strongly lensed Type Ia supernovae using machine learning

Strong lensing in UNIONS: Toward a pipeline from discovery to modeling

Lensed quasar search via time variability with the HSC transient survey

The impact of human expert visual inspection on the discovery of strong gravitational lenses

A Highly Magnified Gravitationally Lensed Red QSO at z = 2.5 with a Significant Flux Ratio Anomaly

Strongly lensed candidates from the HSC transient survey

Survey of Gravitationally Lensed Objects in HSC Imaging (SuGOHI) - VII. Discovery and confirmation of three strongly lensed quasars