Publications (45)
The FIRST Bright Quasar Survey III. The South Galactic Cap
Robert H. Becker, Richard L. White, Michael D. Gregg +9
We present the results of an extension of the FIRST Bright Quasar Survey (FBQS) to the South Galactic cap, and to a fainter optical magnitude limit. Radio source counterparts with…
Gravitational Lensing Accuracy Testing 2010 (GREAT10) Challenge Handbook
Thomas Kitching, Sreekumar Balan, Gary Bernstein +32
GRavitational lEnsing Accuracy Testing 2010 (GREAT10) is a public image analysis challenge aimed at the development of algorithms to analyze astronomical images. Specifically, the…
Discovery of two gravitationally lensed quasars in the Dark Energy Survey
Adriano Agnello, Tommaso Treu, Fernanda Ostrovski +77
We present spectroscopic confirmation of two new lensed quasars via data obtained at the 6.5m Magellan/Baade Telescope. The lens candidates have been selected from the Dark Energy…
Galaxy Image Simulation Using Progressive GANs
Mohamad Dia, Elodie Savary, Martin Melchior +1
In this work, we provide an efficient and realistic data-driven approach to simulate astronomical images using deep generative models from machine learning. Our solution is based o…
Spatial decomposition of on-nucleus spectra of quasar host galaxies
Knud Jahnke, Lutz Wisotzki, Frederic Courbin +1
In order to study the host galaxies of type 1 (broad-line) quasars, we present a semi-analytic modelling method to decompose the on-nucleus spectra of quasars into nuclear and host…
Exploiting flux ratio anomalies to probe warm dark matter in future large scale surveys
David Harvey, Wessel Valkenburg, Amelie Tamone +3
Flux ratio anomalies in strong gravitationally lensed quasars constitute a unique way to probe the abundance of non-luminous dark matter haloes, and hence the nature of dark matter…
A SHARP view of H0LiCOW: from three time-delay gravitational lens systems with adaptive optics imaging
Geoff C. -F. Chen, Christopher D. Fassnacht, Sherry. H. Suyu +20
We present the measurement of the Hubble Constant, , with three strong gravitational lens systems. We describe a blind analysis of both PG1115+080 and HE0435-1223 as well as a…
Discovery of a bright quasar without a massive host galaxy
Pierre Magain, Geraldine Letawe, Frederic Courbin +4
Quasars are thought to be powered by the infall of matter onto a supermassive black hole at the centre of massive galaxies. As the optical luminosity of quasars exceeds that of the…
TDCOSMO XXVI: Uniform lens modeling of eight doubly imaged quasars
Ryan Brady, Xiang-Yu Huang, Simon Birrer +7
We present the first uniform gravitational lens modeling analysis of eight doubly imaged quasars from multi-band observations with the Hubble Space Telescope. Previous time-delay c…
The Third Gravitational Lensing Accuracy Testing (GREAT3) Challenge Handbook
Rachel Mandelbaum, Barnaby Rowe, James Bosch +28
The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is the third in a series of image analysis challenges, with a goal of testing and facilitating the development of me…
Theia: Faint objects in motion or the new astrometry frontier
The Theia Collaboration, Celine Boehm, Alberto Krone-Martins +96
In the context of the ESA M5 (medium mission) call we proposed a new satellite mission, Theia, based on relative astrometry and extreme precision to study the motion of very faint…
Results of the GREAT08 Challenge: An image analysis competition for cosmological lensing
Sarah Bridle, Sreekumar T. Balan, Matthias Bethge +31
We present the results of the GREAT08 Challenge, a blind analysis challenge to infer weak gravitational lensing shear distortions from images. The primary goal was to stimulate new…
H0LiCOW XII. Lens mass model of WFI2033-4723 and blind measurement of its time-delay distance and
Cristian E. Rusu, Kenneth C. Wong, Vivien Bonvin +15
We present the lens mass model of the quadruply-imaged gravitationally lensed quasar WFI2033-4723, and perform a blind cosmographical analysis based on this system. Our analysis co…
A Survey of Dynamical and Gravitational Lensing Tests in Scale Invariance: The Fall of Dark Matter?
Andre Maeder, Frederic Courbin
We first briefly review the adventure of scale invariance in physics, from Galileo Galilei, Weyl, Einstein, and Feynman to the revival by Dirac (1973) and Canuto et al. (1977). We…
Observational tests in scale invariance II: gravitational lensing
Andre Maeder, Frederic Courbin
We study the path of light rays passing near a massive object, in the context of the scale invariant equation of the geodesics first obtained by Dirac (1973). Using the exterior Sc…
Observational tests in scale invariance III: wide binary stars
Andre Maeder, Frederic Courbin
Recent studies of wide binary stars based on Gaia DR3 suggest that the relative orbital velocities of objects with separations s > 3'000 astronomical units are statistically larger…
HOLISMOKES XIX: SN 2025wny at , the first strongly lensed superluminous supernova
Stefan Taubenberger, Ana Acebron, Raoul Cañameras +45
We present imaging and spectroscopic observations of supernova SN 2025wny, associated with the lens candidate PS1 J0716+3821. Photometric monitoring from the Lulin and Maidanak obs…
The DELVE Quadruple Quasar Search I. A Lensed Low Luminosity AGN
Paul L. Schechter, Dominique Sluse, Erik A. Zaborowski +25
A quadruply lensed source, J125856.3-031944, has been discovered using the DELVE survey and WISE W1 - W2 colors. Followup direct imaging carried out with the Magellan Baade 6.5 m t…
Hopfield Neural Network deconvolution for weak lensing measurement
Guldariya Nurbaeva, Malte Tewes, Frederic Courbin +1
Weak gravitational lensing has the potential to place tight constraints on the equation of the state of dark energy. However, this will only be possible if shear measurement method…
Accretion Disk Size Measurement and Time Delays in the Lensed Quasar WFI 2033-4723
Christopher W. Morgan, Gregory E. Hyer, Vivien Bonvin +5
We present 13 seasons of -band photometry of the quadruply-lensed quasar WFI 2033-4723 from the 1.3m SMARTS telescope at CTIO and the 1.2m Euler Swiss Telescope at La Silla, in…
Dark matter dynamics in Abell 3827: new data consistent with standard Cold Dark Matter
Richard Massey, David Harvey, Jori Liesenborgs +23
We present integral field spectroscopy of galaxy cluster Abell 3827, using ALMA and VLT/MUSE. It reveals an unusual configuration of strong gravitational lensing in the cluster cor…
A weak lensing comparability study of galaxy mergers that host AGNs
David Harvey, Frederic Courbin
We compared the total mass density profiles of three different types of galaxies using weak gravitational lensing: (i) 29 galaxies that host quasars at z~0.32 that are in a post-st…
H0LiCOW IV. Lens mass model of HE 0435-1223 and blind measurement of its time-delay distance for cosmology
Kenneth C. Wong, Sherry H. Suyu, Matthew W. Auger +13
Strong gravitational lenses with measured time delays between the multiple images allow a direct measurement of the time-delay distance to the lens, and thus a measure of cosmologi…
H0LiCOW VI. Testing the fidelity of lensed quasar host galaxy reconstruction
Xuheng Ding, Kai Liao, Tommaso Treu +11
The empirical correlation between the mass of a super-massive black hole (MBH) and its host galaxy properties is widely considered to be evidence of their co-evolution. A powerful…
TDCOSMO VIII: A key test of systematics in the hierarchical method of time-delay cosmography
Matthew R. Gomer, Dominique Sluse, Lyne Van de Vyvere +2
The largest source of systematic errors in the time-delay cosmography method likely arises from the lens model mass distribution, where an inaccurate choice of model could in princ…
H0LiCOW XIII. A 2.4% measurement of from lensed quasars: tension between early and late-Universe probes
Kenneth C. Wong, Sherry H. Suyu, Geoff C. -F. Chen +23
We present a measurement of the Hubble constant () and other cosmological parameters from a joint analysis of six gravitationally lensed quasars with measured time delays. A…
Shear measurement bias I: dependencies on methods, simulation parameters and measured parameters
Arnau Pujol, Florent Sureau, Jerome Bobin +3
We present a study of the dependencies of shear bias on simulation (input) and measured (output) parameters, noise, point-spread function anisotropy, pixel size, and the model bias…
Disc colours in field and cluster spiral galaxies at 0.5 < z < 0.8
Nicolas Cantale, Pascale Jablonka, Frederic Courbin +9
We present a detailed study of the colours in late-type galaxy discs for ten of the EDisCS galaxy clusters with 0.5 < z < 0.8. Our cluster sample contains 172 spiral galaxies, and…
Constraining compact dark matter with time-varying quasar equivalent widths
Georgios Vernardos, James Hung Hsu Chan, Frederic Courbin
One of the possible explanations for dark matter is that of compact dark objects of baryonic origin, such as black holes or even planets. Accumulating evidence, including the disco…
Further Evidence that Quasar X-Ray Emitting Regions Are Compact: X-Ray and Optical Microlensing in the Lensed Quasar Q J0158-4325
Christopher W. Morgan, Laura J. Hainline, Bin Chen +9
We present four new seasons of optical monitoring data and six epochs of X-ray photometry for the doubly-imaged lensed quasar Q J0158-4325. The high-amplitude, short-period microle…
Strong Lens Time Delay Challenge: II. Results of TDC1
Kai Liao, Tommaso Treu, Phil Marshall +23
We present the results of the first strong lens time delay challenge. The motivation, experimental design, and entry level challenge are described in a companion paper. This paper…
TDCOSMO. XII. Improved Hubble constant measurement from lensing time delays using spatially resolved stellar kinematics of the lens galaxy
Anowar J. Shajib, Pritom Mozumdar, Geoff C. -F. Chen +12
Strong-lensing time delays enable measurement of the Hubble constant () independently of other traditional methods. The main limitation to the precision of time-delay cosmog…
Lightweight HI source finding for next generation radio surveys
Emma Tolley, Damien Korber, Aymeric Galan +5
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…
A simple fitting method (gfit) for galaxy shape measurement in weak lensing surveys
Marc Gentile, Frederic Courbin, Georges Meylan
It is anticipated that the large sky areas covered by planned wide-field weak lensing surveys will reduce statistical errors to such an extent that systematic errors will instead b…
Weak lensing mass map and peak statistics in Canada-France-Hawaii Telescope Stripe 82 survey
HuanYuan Shan, Jean-Paul Kneib, Johan Comparat +10
We present a weak lensing mass map covering ~124 square degrees of the Canada-France-Hawaii Telescope Stripe 82 Survey (CS82). We study the statistics of rare peaks in the map, inc…
Constraining the low-mass end of the Initial Mass Function with Gravitational Lensing
Ignacio Ferreras, Prasenjit Saha, Dominik Leier +2
The low-mass end of the stellar Initial Mass Function (IMF) is constrained by focusing on the baryon-dominated central regions of strong lensing galaxies. We study in this letter t…
Toward an internally consistent astronomical distance scale
Richard de Grijs, Frederic Courbin, Clara E. Martinez-Vazquez +3
Accurate astronomical distance determination is crucial for all fields in astrophysics, from Galactic to cosmological scales. Despite, or perhaps because of, significant efforts to…
GREAT3 results I: systematic errors in shear estimation and the impact of real galaxy morphology
Rachel Mandelbaum, Barnaby Rowe, Robert Armstrong +40
We present first results from the third GRavitational lEnsing Accuracy Testing (GREAT3) challenge, the third in a sequence of challenges for testing methods of inferring weak gravi…
A Microlensing Accretion Disk Size Measurement in the Lensed Quasar WFI 2026-4536
Matthew A. Cornachione, Christopher W. Morgan, Martin Millon +4
We use thirteen seasons of R-band photometry from the 1.2m Leonard Euler Swiss Telescope at La Silla to examine microlensing variability in the quadruply-imaged lensed quasar WFI 2…
The late afterglow and host galaxy of GRB 990712
Jens Hjorth, Stephen Holland, Frederic Courbin +3
We present deep HST imaging, as well as ground-based imaging and spectroscopy, of the optical afterglow associated with the long-duration gamma-ray burst GRB 990712 and its host ga…
Strong Lensing Science Collaboration input to the on-sky commissioning of the Vera Rubin Observatory
Graham P. Smith, Timo Anguita, Simon Birrer +10
We present the Strong Lensing Science Collaboration's (SLSC) recommended observing targets for the science verification and science validation phases of commissioning. Our recommen…
Probing compact dark matter objects with microlensing in gravitationally lensed quasars
Petra Awad, James H. H. Chan, Martin Millon +2
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 s…
On the ellipticity parameterization for an NFW profile: an overlooked angular structure in strong lens modeling
Matthew R. Gomer, Dominique Sluse, Lyne Van de Vyvere +3
Galaxy-scale gravitational lenses are often modeled with two-component mass profiles where one component represents the stellar mass and the second is an NFW profile representing t…
The Hubble Tension in Light of the Symmetry of Scale Invariance
Frederic Courbin, Andre Maeder
When the expansion rate of the Universe at recombination is used to infer the present expansion rate , the value derived in the CDM model, km/s/mpc, is about in…
An Exploratory Search for z~6 Quasars in the UKIDSS Early Data Release
Eilat Glikman, Alexander Eigenbrod, S. G. Djorgovski +4
We conducted an exploratory search for quasars at z~ 6 - 8, using the Early Data Release from United Kingdom Infrared Deep Sky survey (UKIDSS) cross-matched to panoramic optical im…