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Frédéric Courbin

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Related publications (220)

Page 5 of 11

Polarimetry of the Lyα envelope of the radio-quiet quasar SDSS J124020.91+145535.6

Frédéric Courbin, Pierre North

The radio quiet quasar SDSS J1240+1455 lies at a redshift of z = 3.11, is surrounded by a Ly alpha blob (LAB), and is absorbed by a proximate damped Ly alpha system. In order to better define the morphology of the blob and determine its emission mechanism, ...

Edp Sciences S A2024

Three quasi-stellar objects acting as strong gravitational lenses

Frédéric Courbin, Georges Meylan, Malte Tewes, François Henri Ambroise Rérat

We report the discovery of three new cases of quasi-stellar objects (QSOs) acting as strong gravitational lenses on background emission line galaxies: SDSS J0827+5224 (z(QSO) = 0.293, z(s) = 0.412), SDSS J0919+2720 (z(QSO) = 0.209, z(s) = 0.558), SDSS J100 ...

2012

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

Frédéric Courbin, Hung-Hsu Chan, Vivien François Bonvin, Martin Raoul Robert Millon, Karina Alexandra Rojas Olate

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 ...

OXFORD UNIV PRESS2018

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

Frédéric Courbin, Georges Meylan, Alexander Patrick Eigenbrod

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. ...

2011

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

Frédéric Courbin, Aymeric Alexandre Galan, Austin Chandler Peel, Rémy Elie Joseph

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 ...

EDP SCIENCES S A2021

Spectroscopy of extended Ly alpha envelopes around z=4.5 quasars

Frédéric Courbin, Pierre North, Alexander Patrick Eigenbrod

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 ...

2012

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

Jean-Paul Richard Kneib, Frédéric Courbin, Georges Meylan

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 ...

2025

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

Frédéric Courbin

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 ...

2008

Euclid: The Early Release Observations Lens Search Experiment

Frédéric Courbin, Georges Meylan, Georgios Vernardos, Lucie Anemone Scharré, Bastien Clément

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 ...

2025

Simultaneous estimation of time delays and quasar structure

Frédéric Courbin, Georges Meylan, Christel Vuissoz

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 ...

2008

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

Jean-Paul Richard Kneib, Frédéric Courbin, Danuta Janina Paraficz

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 ...

Oxford Univ Press2016

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

Frédéric Courbin, Georges Meylan

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 ...

2024

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

Frédéric Courbin, Georges Meylan, Malte Tewes

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 ...

Iop Publishing Ltd2012

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

Frédéric Courbin, Vivien François Bonvin, Martin Raoul Robert Millon

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 ...

IOP PUBLISHING LTD2020

Cosmology intertwined: A review of the particle physics, astrophysics, and cosmology associated with the cosmological tensions and anomalies

Frédéric Courbin, Julien Lesgourgues, Mikhail Ivanov, Richard Irving Anderson

The standard Lambda Cold Dark Matter (Lambda CDM) cosmological model provides a good description of a wide range of astrophysical and cosmological data. However, there are a few big open questions that make the standard model look like an approximation to ...

ELSEVIER2022

Ground-based image deconvolution with Swin Transformer UNet

Frédéric Courbin, Pascale Jablonka, Utsav Akhaury

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 ...

2024

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

Frédéric Courbin, Georges Meylan

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 ...

EDP SCIENCES S A2022

Euclid preparation XLI. Galaxy power spectrum modelling in real space

Frédéric Courbin, Georges Meylan

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 ...

2024

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

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

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

COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses

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

2018