A5089474157- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- CCD and CMOS Imaging Sensors
- Speech and Audio Processing
- Statistical and numerical algorithms
- Domain Adaptation and Few-Shot Learning
- Pulsars and Gravitational Waves Research
- History and Developments in Astronomy
- Solar Radiation and Photovoltaics
- Robotic Mechanisms and Dynamics
- Calibration and Measurement Techniques
- Spacecraft Dynamics and Control
- Computational Physics and Python Applications
- Cell Image Analysis Techniques
- Geophysics and Gravity Measurements
- Soil Moisture and Remote Sensing
- Image Processing Techniques and Applications
Technical University of Munich
2023-2025
Max Planck Institute for Astrophysics
2023-2025
First Technical University
2024
École Polytechnique Fédérale de Lausanne
2019-2023
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...
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...
Time-delay cosmography of lensed quasars has achieved 2.4% precision on the measurement Hubble constant, H 0 . As part an ongoing effort to uncover and control systematic uncertainties, we investigate three potential sources: 1- stellar kinematics, 2- line-of-sight effects, 3- deflector mass model. To meet this goal in a quantitative way, reproduced H0LiCOW/SHARP/STRIDES (hereafter TDCOSMO) procedures set real simulated data, find following. First, kinematics cannot be dominant source error...
We performed a search for strong lens galaxy-scale systems in the first data release of Dark Energy Survey (DES), from color-selected parent sample 18~745~029 Luminous Red Galaxies (LRGs). Our was based on Convolutional Neural Network (CNN) to grade our LRG selection with values between 0 (non-lens) and 1 (lens). training set data-driven, i.e. using lensed sources taken HST COSMOS images where light distribution plane directly DES LRGs. A total 76~582 cutouts obtained score above 0.9. These...
ABSTRACT We report the spectroscopic follow-up of 175 lensed quasar candidates selected using Gaia Data Release 2 observations following Paper III this series. Systems include 86 confirmed quasars and a further 17 likely based on imaging and/or similar spectra. also confirm 11 projected pairs physical pairs, while 25 systems are left as unclassified – at same redshift, which could be either distinct or potential quasars. Especially interesting objects eight quadruply imaged two have BAL...
ABSTRACT In recent years, breakthroughs in methods and data have enabled gravitational time delays to emerge as a very powerful tool measure the Hubble constant H0. However, published state-of-the-art analyses require of order 1 yr expert investigator up million hours computing per system. Furthermore, precision improves, it is crucial identify mitigate systematic uncertainties. With this delay lens modelling challenge, we aim assess level accuracy techniques that are currently fast enough...
In the context of gravitational lensing, density profile lensing galaxies is often considered to be perfectly elliptical. Potential angular structures are generally ignored, except explain flux ratios anomalies. Surprisingly, impact azimuthal on extended images source has not been characterized, nor its H0 inference. We address this task by creating mock a point embedded in an source, lensed elliptical galaxy which multipolar components added emulate boxy/discy isodensity contours. Modeling...
The importance of alternative methods for measuring the Hubble constant, such as time-delay cosmography, is highlighted by recent tension. It paramount to thoroughly investigate and rule out systematic biases in all measurement before we can accept new physics source this In study, perform a check lens modelling procedure cosmography comparing independent blind predictions system WGD 2038−4008 from two teams using different software programs: GLEE LENSTRONOMY . predicted time delays...
Modeling the mass distribution of galaxy-scale strong gravitational lenses is a task increasing difficulty. The high-resolution and depth imaging data now available render simple analytical forms ineffective at capturing lens structures spanning large range in spatial scale, morphology. In this work, we address problem with novel multiscale method based on wavelets. We tested our simulated Hubble Space Telescope (HST) containing following different types substructures making them deviate...
The Square Kilometre Array Observatory (SKAO) will explore the radio sky to new depths in order conduct transformational science. SKAO data products made available astronomers be correspondingly large and complex, requiring application of advanced analysis techniques extract key science findings. To this end, is conducting a series Science Data Challenges, each designed familiarise scientific community with drive development techniques. We present results from Challenge 2 (SDC2), which...
We report the discovery of a complete Einstein ring around elliptical galaxy NGC 6505, at $z=0.042$. This is first strong gravitational lens discovered in Euclid and an object from any survey. The combination low redshift galaxy, brightness source ($I_\mathrm{E}=18.1$ lensed, $I_\mathrm{E}=21.3$ unlensed), completeness make this exceptionally rare lens, unidentified until its observation by Euclid. present deep imaging data Visible Camera (VIS) Near-Infrared Spectrometer Photometer (NISP)...
We present new time delays, the main ingredient of delay cosmography, for 22 lensed quasars resulting from high-cadence r -band monitoring on 2.6$,m ESO VLT Survey Telescope and Max-Planck-Gesellschaft 2.2,$m telescope. Each quasar was typically monitored one to four seasons, often shared between two telescopes mitigate interruptions forced by COVID-19 pandemic. The sample targets consists 19 quadruply 3 doubly imaged quasars, which received a total 1$,$918 hours on-sky split into 21$,$581...
Strong gravitational lensing provides a wealth of astrophysical information on the baryonic and dark matter content galaxies. It also serves as valuable cosmological probe by allowing us to measure Hubble constant independently other methods. These applications all require difficult task inverting lens equation simultaneously reconstructing mass profile along with original light unlensed source. As there is no reason for either or source be simple, we need methods that both invert large...
Time-delay cosmography is a powerful technique to constrain cosmological parameters, particularly the Hubble constant ( H 0 ). The TDCOSMO Collaboration performing an ongoing analysis of lensed quasars cosmology using this method. In work, we obtain constraints from quasar WGD 2038−4008 new time-delay measurements and previous mass models by TDCOSMO. This first lens incorporate multiple modeling codes full covariance matrix into inference. are fixed before time delay measured, performed...
Challenges inherent to high-resolution and high signal-to-noise data as well model degeneracies can cause systematic biases in analyses of strong lens systems. In the past decade, number modeling methods has significantly increased, from purely analytical methods, pixelated non-parametric ones, or ones based on deep learning. We embraced this diversity by selecting different software packages use them blindly independently simulated Hubble Space Telescope (HST) imaging data. To overcome...
One of the main challenges in using high redshift active galactic nuclei to study correlations between mass supermassive Black Hole (MBH) and properties their host galaxies is instrumental resolution. Strong lensing magnification effectively increases resolution thus helps address this challenge. In work, we eight strongly lensed (AGN) with deep Hubble Space Telescope imaging, lens modelling code Lenstronomy reconstruct image source. Using reconstructed brightness galaxy, infer galaxy...
Strong gravitational lensing is a unique observational tool for studying the dark and luminous mass distribution both within between galaxies. Given presence of substructures, current strong observations demand more complex models than smooth analytical profiles, such as power-law ellipsoids. In this work, we introduce continuous neural field to predict potential at any position throughout image plane, allowing nearly model-independent description mass. We applied our method simulated Hubble...
Gravitational lensing by galaxy clusters involves hundreds of galaxies over a large redshift range and increases the likelihood rare phenomena (supernovae, microlensing, dark substructures, etc.). Characterizing mass light distributions foreground background objects often requires combination high-resolution data advanced modeling techniques. We present detailed analysis El Anzuelo, prominent quintuply imaged dusty star-forming (ɀ s = 2.29), mainly lensed three members massive cluster ACT-CL...
We present a mass measurement for the secondary lens along line of sight (LoS) from multi-plane strong modeling group-scale CASSOWARY 31 (CSWA 31). The at redshift z = 1.49 is spiral galaxy well aligned LoS with main 0.683. Using MUSE integral-field spectroscopy this galaxy, we measured its rotation velocities and determined gas kinematics. compared estimation lensing models to kinematics, finding that predictions tend be higher. By introducing an additional plane 1.36 overdensity known...
lenstronomy is an Astropy-affiliated Python package for gravitational lensing simulations and analyses. was introduced by Birrer Amara (2018) based on the linear basis set approach et a. (2015). The user developer base of has substantially grown since then, software become integral part a wide range recent analyses, such as measuring Hubble constant with time-delay strong or constraining nature dark matter from resolved unresolved small scale distortion statistics. modular design allowed...
We present the proof of concept a method for finding strongly lensed quasars using their spatially extended photometric variability through difference imaging in cadenced survey data. applied to Pan-STARRS, starting with an initial selection 14 107 Gaia multiplets quasar-like infrared colours from WISE. identified 229 candidates showing notable during Pan-STARRS period. These include 20 known lenses and additional 12 promising which we obtained long-slit spectroscopy follow-up. This process...
Strong gravitational lensing is a powerful tool to provide constraints on galaxy mass distributions and cosmological parameters, such as the Hubble constant, $H_0$. Nevertheless, inference of parameters from images systems not trivial parameter degeneracies can limit precision in measured lens results. External information lens, form kinematic measurements, needed ensure precise unbiased inference. Traditionally, has been included after image modeling, using spherical Jeans approximations...