Publications by Eric Gérard Guy Paic

Predicting High-magnification Events in Microlensed Quasars in the Era of LSST Using Recurrent Neural Networks

Upcoming wide-field surveys, such as the Rubin Observatory's Legacy Survey of Space and Time (LSST), will monitor thousands of strongly lensed quasars over a 10 yr period. Many of these monitored quasars will undergo high-magnification events (HMEs) throug ...

IOP Publishing Ltd2025

J1721+8842: The first Einstein zigzag lens

Eric Gérard Guy Paic

We report the discovery of the first example of an Einstein zigzag lens, an extremely rare lensing configuration. In this system, J1721+8842, six images of the same background quasar are formed by two intervening galaxies, one at redshift z(1) = 0.184 and ...

EDP SCIENCES S A2025

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, Vivien François Bonvin, Aymeric Alexandre Galan, Eric Gérard Guy Paic, 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

Probing compact dark matter objects with microlensing in gravitationally lensed quasars

Frédéric Courbin, Martin Raoul Robert Millon, Eric Gérard Guy Paic, Hung-Hsu Chan, Petra Awad

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 ...

EDP SCIENCES S A2023

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

Frédéric Courbin, Elodie Marie Charlène Savary, Martin Raoul Robert Millon, Eric Gérard Guy Paic, Rémy Elie Joseph, Hung-Hsu Chan, Karina Alexandra Rojas Olate, Benjamin Yvan Alexandre Clement, Yue Pan

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 ...

OXFORD UNIV PRESS2023

Strong and micro lensing in distant quasars

Eric Gérard Guy Paic

Most large galaxies contain Super Massive Black Holes at their centers, drawing matter nearby to form swirling accretion disks emitting electromagnetic radiation. These are Active Galactic Nuclei. The brightest quasars are the most luminous Universe object ...

EPFL2023

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

Frédéric Courbin, Vivien François Bonvin, Martin Raoul Robert Millon, Eric Gérard Guy Paic, Hung-Hsu Chan, Georgios Vernardos

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 ...

EDP SCIENCES S A2022

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

Frédéric Courbin, Martin Raoul Robert Millon, Eric Gérard Guy Paic, Hung-Hsu Chan, Cameron Alexander Campbell Lemon, Adriano Agnello

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 ...

EDP SCIENCES S A2022

Discovery of strongly lensed quasars in the Ultraviolet Near Infrared Optical Northern Survey (UNIONS)

Elodie Marie Charlène Savary, Martin Raoul Robert Millon, Eric Gérard Guy Paic, Hung-Hsu Chan, Karina Alexandra Rojas Olate, Benjamin Yvan Alexandre Clement, Cameron Alexander Campbell Lemon, Georgios Vernardos

We report the discovery of five new doubly imaged lensed quasars from the first 2500 square degrees of the ongoing Canada-France Imaging Survey (CFIS), which is a component of the Ultraviolet Near Infrared Optical Northern Survey. The systems are preselect ...

EDP SCIENCES S A2022

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

Frédéric Courbin, Martin Raoul Robert Millon, Eric Gérard Guy Paic, Hung-Hsu Chan, Cameron Alexander Campbell Lemon

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, ...

EDP SCIENCES S A2022

COSMOGRAIL: XIX. Time delays in 18 strongly lensed quasars from 15 years of optical monitoring star

Malte Tewes, Georges Meylan, Frédéric Courbin, Vivien François Bonvin, Martin Raoul Robert Millon, Aymeric Alexandre Galan, Eric Gérard Guy Paic, Rémy Elie Joseph, Olga Tihhonova, Hung-Hsu Chan, Cameron Alexander Campbell Lemon

We present the results of 15 years of monitoring lensed quasars, which was conducted by the COSMOGRAIL programme at the Leonhard Euler 1.2 m Swiss Telescope. The decade-long light curves of 23 lensed systems are presented for the first time. We complement ...

EDP SCIENCES S A2020

TDCOSMO II. Six new time delays in lensed quasars from high-cadence monitoring at the MPIA 2.2m telescope

Frédéric Courbin, Sun Hee Kim, Vivien François Bonvin, Martin Raoul Robert Millon, Eric Gérard Guy Paic, Hung-Hsu Chan, Karina Alexandra Rojas Olate, Cameron Alexander Campbell Lemon, Adriano Agnello

We present six new time-delay measurements obtained from Rc-band monitoring data acquired at the Max Planck Institute for Astrophysics (MPIA) 2.2m telescope at La Silla observatory between October 2016 and February 2020. The lensed quasars HE0047 1756, WG0 ...

EDP SCIENCES S A2020

COSMOGRAIL XVII. Time delays for the quadruply imaged quasar PG 1115+080

Malte Tewes, Georges Meylan, Frédéric Courbin, Sun Hee Kim, Vivien François Bonvin, Martin Raoul Robert Millon, Eric Gérard Guy Paic, Hung-Hsu Chan, Karina Alexandra Rojas Olate

We present time-delay estimates for the quadruply imaged quasar PG 1115+080. Our results are based on almost daily observations for seven months at the ESO MPIA 2.2m telescope at La Silla Observatory, reaching a signal-to-noise ratio of about 1000 per quas ...

EDP SCIENCES S A2018

COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses

Eduardo Sanchez, Malte Tewes, Georges Meylan, Frédéric Courbin, Sun Hee Kim, Vivien François Bonvin, Eric Gérard Guy Paic, Karina Alexandra Rojas Olate, Adriano Agnello

2018