Publications de Aymeric Alexandre Galan

Tdcosmo Xvii. New Time Delays in 22 Lensed Quasars From Optical Monitoring with the Eso-vst 2.6m and Mpg 2.2m Telescopes

Frédéric Courbin, Eric Gérard Guy Paic, Vivien François Bonvin, Aymeric Alexandre Galan, Cameron Alexander Campbell Lemon

We present new time delays, the main ingredient of time delay cosmography, for 22 lensed quasars resulting from high-cadence r-band monitoring on the 2.6 m ESO VLT Survey Telescope and Max-Planck-Gesellschaft 2.2 m telescope. Each lensed quasar was typical ...

EDP SCIENCES S A2025

Exploiting the diversity of modeling methods to probe systematic biases in strong lensing analyses

Aymeric Alexandre Galan

Challenges inherent to high-resolution and high signal-to-noise data as well as model degeneracies can cause systematic biases in analyses of strong lens systems. In the past decade, the number of lens modeling methods has significantly increased, from pur ...

EDP SCIENCES S A2024

Nine lensed quasars and quasar pairs discovered through spatially extended variability in Pan-STARRS

Frédéric Courbin, Aymeric Alexandre Galan, Cameron Alexander Campbell Lemon

We present the proof of concept of a method for finding strongly lensed quasars using their spatially extended photometric variability through difference imaging in cadenced imaging survey data. We applied the method to Pan-STARRS, starting with an initial ...

Edp Sciences S A2024

Gravitationally lensed quasars in Gaia - IV. 150 new lenses, quasar pairs, and projected quasars

Frédéric Courbin, Aymeric Alexandre Galan, Cameron Alexander Campbell Lemon, Adriano Agnello

We report the spectroscopic follow-up of 175 lensed quasar candidates selected using Gaia Data Release 2 observations following Paper III of this series. Systems include 86 confirmed lensed quasars and a further 17 likely lensed quasars based on imaging an ...

OXFORD UNIV PRESS2023

SKA Science Data Challenge 2: analysis and results

Jean-Paul Richard Kneib, Xin Chen, Frédéric Courbin, Jean-Luc Starck, Emma Elizabeth Tolley, Yi Zhang, Lei Zhang, Hua Zhang, Xiuwei Zhang, Libo Yu

The Square Kilometre Array Observatory (SKAO) will explore the radio sky to new depths in order to conduct transformational science. SKAO data products made available to astronomers will be correspondingly large and complex, requiring the application of ad ...

OXFORD UNIV PRESS2023

Accelerating galaxy dynamical modeling using a neural network for joint lensing and kinematic analyses

Aymeric Alexandre Galan, Georgios Vernardos

Strong gravitational lensing is a powerful tool to provide constraints on galaxy mass distributions and cosmological parameters, such as the Hubble constant, H0. Nevertheless, inference of such parameters from images of lensing systems is not trivial as pa ...

Edp Sciences S A2023

Strong gravitational lensing by AGNs as a probe of the quasar-host relations in the distant Universe

Frédéric Courbin, Malte Tewes, Martin Raoul Robert Millon, Aymeric Alexandre Galan

A rare case of a quasar acting as a gravitational lens allows a precise determination of the mass of the quasar's host galaxy and offers a new path to studying the connections between supermassive black holes and their host galaxies. ...

NATURE PORTFOLIO2023

Lightweight HI source finding for next generation radio surveys

Jean-Paul Richard Kneib, Frédéric Courbin, Emma Elizabeth Tolley, Aymeric Alexandre Galan, Austin Chandler Peel, Mark Thomas Sargent

Future deep HI surveys will be essential for understanding the nature of galaxies and the content of the Universe. However, the large volume of these data will require distributed and automated processing techniques. We introduce LiSA, a set of python modu ...

ELSEVIER2022

Using wavelets to capture deviations from smoothness in galaxy-scale strong lenses

Frédéric Courbin, Aymeric Alexandre Galan, Georgios Vernardos, Austin Chandler Peel

Modeling the mass distribution of galaxy-scale strong gravitational lenses is a task of increasing difficulty. The high-resolution and depth of imaging data now available render simple analytical forms ineffective at capturing lens structures spanning a la ...

EDP SCIENCES S A2022

Next generation modeling techniques for strong gravitational lensing and measuring the Hubble constant

Aymeric Alexandre Galan

For many years, observations of the Universe suggest a series problems with our theoretical models, particularly its dark energy and dark matter components. Fortunately, the Universe also provides us with a tool to solve these problems, called strong gravi ...

EPFL2022