Publications de Frédéric Courbin

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Time-delay strong lensing provides a unique way to directly measure the Hubble constant (H-0). The precision of the H-0 measurement depends on the uncertainties in the time-delay measurements, the mass distribution of the main deflector(s), and the mass di ...

Aims. We aim to use microlensing taking place in the lensed quasar QSO 2237+0305 to study the structure of the broad line region (BLR) and measure the size of the region emitting the C-IV and C-III] lines. ...

Strong gravitational lensing provides a wealth of astrophysical information on the baryonic and dark matter content of galaxies. It also serves as a valuable cosmological probe by allowing us to measure the Hubble constant independently of other methods. T ...

What are the frequency, shape, kinematics, and luminosity of Ly alpha envelopes surrounding radio-quiet quasars at high redshift, and is the luminosity of these envelopes related to that of the quasar or not? As a first step towards answering these questio ...

We present the first analysis of the Euclid Early Release Observations (ERO) program that targets fields around two lensing clusters, Abell 2390 and Abell 2764. We use imaging data from the Visible instrument (VIS) and the Near-Infrared Spectrometer and Ph ...

host galaxies of six nearby QSOs are studied on the basis of high-resolution HST optical images and spatially resolved VLT slit spectra. The gas ionization and velocity are mapped as a function of the distance to the central QSO. In the majority of the cas ...

We investigated the ability of the Euclid telescope to detect galaxy-scale gravitational lenses. To do so, we performed a systematic visual inspection of the 0.7 deg2 Euclid Early Release Observations data towards the Perseus cluster using both the high-re ...

We expand our Bayesian Monte Carlo method for analyzing the light curves of gravitationally lensed quasars to simultaneously estimate time delays and the sizes of quasar continuum emission regions including their mutual uncertainties. We apply the method t ...

We present a study on galaxy detection and shape classification using topometric clustering algorithms. We first use the DBSCAN algorithm to extract, from CCD frames, groups of adjacent pixels with significant fluxes and we then apply the DENCLUE algorithm ...

Multi-object spectroscopic galaxy surveys typically make use of photometric and colour criteria to select their targets. That is not the case of Euclid, which will use the NISP slitless spectrograph to record spectra for every source over its field of view ...

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 microlensing variability for which this system is known has historically precluded ...

We use 13 seasons of R-band photometry from the 1.2 m Leonard Euler Swiss Telescope at La Silla to examine microlensing variability in the quadruply imaged lensed quasar WFI 2026-4536. The lightcurves exhibit similar to 0.2 mag of uncorrelated variability ...

Aims. As ground-based all-sky astronomical surveys will gather millions of images in the coming years, a critical requirement emerges for the development of fast deconvolution algorithms capable of efficiently improving the spatial resolution of these imag ...

Context. The standard cosmological model is based on the fundamental assumptions of a spatially homogeneous and isotropic universe on large scales. An observational detection of a violation of these assumptions at any redshift would immediately indicate th ...

We investigate the accuracy of the perturbative galaxy bias expansion in view of the forthcoming analysis of the Euclid spectroscopic galaxy samples. We compare the performance of a Eulerian galaxy bias expansion using state-of-the-art prescriptions from t ...

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 ...

The Euclid mission, designed to map the geometry of the dark Universe, presents an unprecedented opportunity for advancing our understanding of the cosmos through its photometric galaxy cluster survey. Central to this endeavor is the accurate calibration o ...

Context. The European Space Agency’s Euclid mission is one of a raft of forthcoming large-scale cosmology surveys that will map the large-scale structure in the Universe with unprecedented precision. The mission will collect a vast amount of data that will ...

The next generation of space-based telescopes used for weak lensing surveys will require exquisite point spread function (PSF) determination. Previously negligible effects may become important in the reconstruction of the PSF, in part because of the improv ...

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 ...

Frédéric Courbin

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Constraining the microlensing effect on time delays with a new time-delay prediction model in H-0 measurements

Zooming into the broad line region of the gravitationally lensed quasar QSO 2237+0305 equivalent to the Einstein Cross III. Determination of the size and structure of the C-IV and C-III] emitting regions using microlensing

SLITRONOMY: Towards a fully wavelet-based strong lensing inversion technique

Spectroscopy of extended Ly alpha envelopes around z=4.5 quasars

Euclid: Early Release Observations – A preview of the Euclid era through a galaxy cluster magnifying lens

Understanding the relations between QSOs and their host galaxies from combined HST imaging and VLT spectroscopy

Euclid: The Early Release Observations Lens Search Experiment

Simultaneous estimation of time delays and quasar structure

ASTErIsM: application of topometric clustering algorithms in automatic galaxy detection and classification

Euclid: Testing photometric selection of emission-line galaxy targets?

Further Evidence That Quasar X-Ray Emitting Regions Are Compact: X-Ray And Optical Microlensing In The Lensed Quasar Q J0158-4325

A Microlensing Accretion Disk Size Measurement in the Lensed Quasar WFI 2026-4536

Ground-based image deconvolution with Swin Transformer UNet

Euclid: Forecast constraints on consistency tests of the ?CDM model

Euclid preparation XLI. Galaxy power spectrum modelling in real space

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

Euclid preparation: L. Calibration of the halo linear bias in Λ(v)CDM cosmologies

Euclid preparation XLVIII. The pre-launch Science Ground Segment simulation framework

Evaluating the effect of stellar multiplicity on the point spread function of space-based weak lensing surveys

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