A5000309781- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Cosmology and Gravitation Theories
- Astrophysics and Star Formation Studies
- Calibration and Measurement Techniques
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Atmospheric Ozone and Climate
- Geophysics and Gravity Measurements
- Pulsars and Gravitational Waves Research
- History and Developments in Astronomy
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Advanced Measurement and Metrology Techniques
- Relativity and Gravitational Theory
- Dark Matter and Cosmic Phenomena
- Advanced Mathematical Theories and Applications
- Solar Radiation and Photovoltaics
- Mathematics and Applications
- Advanced Vision and Imaging
University of Liège
2015-2024
Centre de Recherche en Astronomie Astrophysique et Géophysique
2015-2021
Royal Belgian Institute for Space Aeronomy
2005-2019
Indian Institute of Astrophysics
2019
Laboratoire d’Études en Géophysique et Océanographie Spatiales
2003-2017
University of Bonn
2011-2015
Heidelberg University
2008-2012
École Polytechnique Fédérale de Lausanne
2006-2010
Agruicultural Research Institute
2010
Institute of Astronomy
2008
We present a measurement of the Hubble constant ($H_{0}$) and other cosmological parameters from joint analysis six gravitationally lensed quasars with measured time delays. All lenses except first are analyzed blindly respect to parameters. In flat $\Lambda$CDM cosmology, we find $H_{0} = 73.3_{-1.8}^{+1.7}$, 2.4% precision measurement, in agreement local measurements $H_{0}$ type Ia supernovae calibrated by distance ladder, but $3.1\sigma$ tension $Planck$ observations cosmic microwave...
We present a new measurement of the Hubble Constant H0 and other cosmological parameters based on joint analysis three multiply-imaged quasar systems with measured gravitational time delays. First, we measure delay HE0435-1223 from 13-year light curves obtained as part COSMOGRAIL project. Companion papers detail modeling main deflectors line sight effects, how these data are combined to determine time-delay distance HE 0435-1223. Crucially, measurements carried out blindly respect in order...
Strong gravitational lenses with measured time delays between the multiple images and models of lens mass distribution allow a one-step determination time-delay distance, thus measure cosmological parameters. We present blind analysis RXJ1131-1231 incorporating (1) newly from COSMOGRAIL, (2) archival HST imaging system, (3) new velocity-dispersion measurement galaxy 323+/-20km/s based on Keck spectroscopy, (4) characterization line-of-sight structures via observations lens' environment ray...
We present a blind time-delay strong lensing (TDSL) cosmographic analysis of the doubly imaged quasar SDSS 1206+4332 . combine relative time delay between images, Hubble Space Telescope imaging, Keck stellar velocity dispersion galaxy, and wide-field photometric spectroscopic data field to constrain two angular diameter distance relations. The combined is performed by forward modelling individual sets through Bayesian hierarchical framework, it kept until very end prevent experimenter bias....
Strong gravitational lens systems with time delays between the multiple images allow measurements of time-delay distances, which are primarily sensitive to Hubble constant that is key probing dark energy, neutrino physics, and spatial curvature Universe, as well discovering new physics. We present H0LiCOW ($H_0$ Lenses in COSMOGRAIL's Wellspring), a program aims measure $H_0$ $<3.5\%$ uncertainty from five (B1608+656, RXJ1131-1231, HE0435-1223, WFI2033-4723 HE1104-1805). have been acquiring...
The H0LiCOW collaboration inferred via strong gravitational lensing time delays a Hubble constant value of H 0 = 73.3 −1.8 +1.7 km s −1 Mpc , describing deflector mass density profiles by either power-law or stars (constant mass-to-light ratio) plus standard dark matter halos. mass-sheet transform (MST) that leaves the observables unchanged is considered dominant source residual uncertainty in . We quantify any potential effect MST with flexible family models, which directly encodes it, and...
We present the measurement of Hubble Constant, $H_0$, with three strong gravitational lens systems. describe a blind analysis both PG1115+080 and HE0435-1223 as well an extension our previous RXJ1131-1231. For each lens, we combine new adaptive optics (AO) imaging from Keck Telescope, obtained part SHARP AO effort, Space Telescope (HST) imaging, velocity dispersion measurements, description line-of-sight mass distribution to build accurate precise model. This model is then combined...
ABSTRACT We present a blind time-delay cosmographic analysis for the lens system DES J0408−5354. This is extraordinary presence of two sets multiple images at different redshifts, which provide opportunity to obtain more information cost increased modelling complexity with respect previously analysed systems. perform detailed mass distribution this using three band Hubble Space Telescope imaging. combine measured time delays, line-of-sight central velocity dispersion deflector, and...
Strong gravitational lenses with measured time delays between the multiple images allow a direct measurement of time-delay distance to lens, and thus measure cosmological parameters, particularly Hubble constant, $H_{0}$. We present blind lens model analysis quadruply-imaged quasar HE 0435-1223 using deep Space Telescope imaging, updated measurements from COSmological MOnitoring GRAvItational Lenses (COSMOGRAIL), velocity dispersion galaxy based on Keck data, characterization mass...
Strong-lensing time delays enable measurement of the Hubble constant ($H_{0}$) independently other traditional methods. The main limitation to precision time-delay cosmography is mass-sheet degeneracy (MSD). Some previous TDCOSMO analyses broke MSD by making standard assumptions about mass density profile lens galaxy, reaching 2% from seven lenses. However, this approach could potentially bias $H_0$ or underestimate errors. In work, for first time, we break using spatially resolved...
We present the results from nine years of optically monitoring gravitationally lensed z=0.658 quasar RX J1131-1231. The R-band light curves four individual images were obtained using deconvolution photometry for a total 707 epochs. Several sharp variability features strongly constrain time delays between images. Using three different numerical techniques, we measure these all possible pairs while always processing simultaneously. For methods, close A, B, and C are compatible with being 0,...
The light travel time differences in strong gravitational lensing systems allows an independent determination of the Hubble constant. This method has been successfully applied to several lens systems. formally most precise measurements are, however, tension with recent $H_0$ from Planck satellite for a spatially flat six-parameters $ΛCDM$ cosmology. We reconsider uncertainties method, concerning mass profile galaxies, and show that formal precision relies on assumption is perfect power law....
Discrepancies between the observed and model-predicted radio flux ratios are seen in a number of quadruply-lensed quasars. The most favored interpretation these anomalies is that CDM substructures present lensing galaxies perturb lens potentials alter image magnifications thus ratios. So far no consensus has emerged regarding whether or not predicted substructure abundance fully accounts for anomaly observations. Accurate modeling relies on realistic sample terms both environment internal...
We present the lens mass model of quadruply-imaged gravitationally lensed quasar WFI2033-4723, and perform a blind cosmographical analysis based on this system. Our combines (1) time-delay measurements from 14 years data obtained by COSmological MOnitoring GRAvItational Lenses (COSMOGRAIL) collaboration, (2) high-resolution $\textit{Hubble Space Telescope}$ imaging, (3) measurement velocity dispersion galaxy ESO-MUSE data, (4) multi-band, wide-field imaging spectroscopy characterizing...
Based on spectroscopy and multiband wide-field observations of the gravitationally lensed quasar HE 0435-1223, we determine probability distribution function external convergence $\kappa_\mathrm{ext}$ for this system. We measure under/overdensity line sight towards lens system compare it to average throughout universe, determined by using CFHTLenS as a control field. Aiming constrain tightly possible, under/overdensities various combinations relevant informative weighing schemes galaxy...
Context. Since April 5, 2008 and up to February 15, 2017, the SOLar SPECtrometer (SOLSPEC) instrument of SOLAR payload on board International Space Station (ISS) has performed accurate measurements solar spectral irradiance (SSI) from middle ultraviolet infrared (165 3088 nm). These are primary importance for a better understanding physics impact variability climate. In particular, new reference spectrum (SOLAR-ISS) is established in during minima cycles 23–24 thanks revised engineering...
Strong gravitational lensing provides a powerful test of cold dark matter (CDM) as it enables the detection and mass measurement low-mass haloes even if they do not contain baryons. Compact lensed sources such active galactic nuclei (AGNs) are particularly sensitive to perturbing subhaloes, but their use CDM has been limited by small number systems which have significant radio emission that is extended enough avoid stars in plane lens galaxy, red be minimally affected differential dust...
Abstract Of order one in $10^{3}$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mn>3</mml:mn> </mml:msup> </mml:math> quasars and high-redshift galaxies appears the sky as multiple images a result of gravitational lensing by unrelated clusters that happen to be foreground. While basic phenomenon is straightforward consequence general relativity, there are many non-obvious consequences make multiple-image systems (aka...
Abstract Strong gravitational lensing of quasars has the potential to unlock poorly understood physics these fascinating objects, as well serve a probe mass distribution and cosmological parameters. In particular, microlensing by compact bodies in galaxy can enable mapping quasar structure $<10^{-6}$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo><</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>6</mml:mn> </mml:mrow> </mml:msup>...
Based on a new sample of 355 quasars with significant optical polarization and using complementary statistical methods, we confirm that quasar vectors are not randomly oriented over the sky probability often in excess 99.9%. The appear coherently or aligned huge (~1 Gpc) regions located at both low () high redshifts characterized by different preferred directions polarization. In fact, there seems to exist regular alternance along line sight typical comoving length scale 1.5 Gpc....
We present accurate time delays for the quadruply imaged quasar HE 0435-1223. The were measured from 575 independent photometric points obtained in R-band between January 2004 and March 2010. With seven years of data, we clearly show that image A is affected by strong microlensing variations are best expressed relative to B. Delta_t(BC) = 7.8+/-0.8 days, Delta_t(BD) -6.5+/-0.7 days Delta_t_CD -14.3+/-0.8 days. spacially deconvolved HST NICMOS2 F160W images derive astrometry infer light...
The main obstacle that gravitational lensing has in determining accurate masses of deflectors, or precise estimates for the Hubble constant, is degeneracy observables with respect to mass-sheet transformation (MST). MST a global modification mass distribution which leaves all image positions, shapes, and flux ratios invariant, but changes time delay. Here we show another distributions exists positions almost special case. As case MST, this new only applies if one considers those source...
A power-law density model, i.e., $\rho(r) \propto r^{-\gamma'}$ has been commonly employed in strong gravitational lensing studies, including the so-called time-delay technique used to infer Hubble constant $H_0$. However, since radial scale at which features are formed corresponds transition from dominance of baryonic matter dark matter, there is no known reason why galaxies should follow a power law density. The assumption artificially breaks mass-sheet degeneracy, well-known invariance...