A5048784698- Radio Astronomy Observations and Technology
- Superconducting and THz Device Technology
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Radio Wave Propagation Studies
- Galaxies: Formation, Evolution, Phenomena
- Geophysics and Gravity Measurements
- Gyrotron and Vacuum Electronics Research
- Target Tracking and Data Fusion in Sensor Networks
- Antenna Design and Optimization
- Geophysics and Sensor Technology
- Gamma-ray bursts and supernovae
- Optical Systems and Laser Technology
- Seismic Imaging and Inversion Techniques
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Scientific Research and Discoveries
Laboratoire de Physique de l'ENS
2023-2024
École Normale Supérieure - PSL
2023-2024
Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères
2023-2024
Université Paris Sciences et Lettres
2023
Sorbonne Université
2023
Université Paris Cité
2023
Centre National de la Recherche Scientifique
2023
Sorbonne Paris Cité
2023
Imperial College London
2020
The redshifted 21 cm signal from neutral hydrogen is a direct probe of the physics early universe and has been an important science driver many present upcoming radio interferometers. In this study we use single night observations with New Extension in Nançay Upgrading LOFAR (NenuFAR) to place upper limits on power spectrum cosmic dawn at redshift z = 20.3. NenuFAR new low-frequency interferometer, operating 10–85 MHz frequency range, currently under construction Radio Observatory France. It...
We compare various foreground removal techniques that are being utilised to remove bright foregrounds in experiments aiming detect the redshifted 21cm signal of neutral hydrogen from Epoch Reionization. In this work, we test performance (FastICA, GMCA, and GPR) on 10 nights LOFAR data investigate possibility recovering latest upper limit signal. Interestingly, find GMCA FastICA reproduce most recent 2$\sigma$ $\Delta^2_{21} <$ (73)$^2$ mK$^2$ at $k=0.075~ h \mathrm{cMpc}^{-1}$, which...
Studying the redshifted 21-cm signal from neutral hydrogen during Epoch of Reionisation and Cosmic Dawn is fundamental for understanding physics early universe. One challenges that experiments face contamination by bright foreground sources, such as Cygnus,A, which accurate spatial spectral models are needed to minimise residual after their removal. In this work, we develop a new, high-resolution model Cygnus,A using Low Frequency Array (LOFAR) observations in 110--250,MHz range, improving...
We propose a new approach to improve the precision of astrophysical parameter constraints for 21cm signal from epoch reionisation (EoR). Our method introduces sets summary statistics, hereafter `evolution compressed' which quantify spectral evolution 2D spatial statistics computed at fixed redshift. defined such compressed power spectrum (PS), wavelet scattering transforms (WST), and moments (WM), also characterise non-Gaussian features. To compare these different along with 3D spectrum, we...
ABSTRACT Numerous studies have established the theoretical potential of 21-cm bispectrum to boost our understanding Epoch Reionization (EoR). We take a first look at impact foregrounds (FGs) and instrumental effects on ability measure it. Unlike power spectrum for which (in absence effects) there is window clear smooth-spectrum FGs in it may be detectable, no such ‘EoR window’ bispectrum. For triangle configurations scales we consider, EoR structures are completely swamped by those FGs, + FG...
ABSTRACT In recent years, a Gaussian process regression (GPR)-based framework has been developed for foreground mitigation from data collected by the LOw-Frequency ARray (LOFAR), to measure 21-cm signal power spectrum Epoch of Reionization (EoR) and cosmic dawn. However, it noted that through this method there can be significant amount loss if EoR covariance is misestimated. To obtain better models, we propose use kernel trained on grizzly simulations using Variational Auto-Encoder...
A detection of the 21-cm signal power spectrum from Epoch Reionization is imminent, thanks to consistent advancements telescopes such as LOFAR, MWA, and HERA, along with development SKA. In light this progress, it crucial expand parameter space simulations used infer astrophysical properties signal. work, we explore role cosmological parameters Hubble constant $H_0$ matter clustering amplitude $\sigma_8$, whose values provided by measurements at different redshifts are in tension. We run...
The redshifted 21 cm signal from neutral hydrogen is a direct probe of the physics early universe and has been an important science driver many present upcoming radio interferometers. In this study we use single night observations with New Extension in Nan\c{c}ay Upgrading LOFAR (NenuFAR) to place upper limits on power spectrum cosmic dawn at redshift $z$ = 20.3. NenuFAR new low-frequency interferometer, operating 10-85 MHz frequency range, currently under construction Radio Observatory...
In recent years, a Gaussian Process Regression (GPR) based framework has been developed for foreground mitigation from data collected by the LOw-Frequency ARray (LOFAR), to measure 21-cm signal power spectrum Epoch of Reionization (EoR) and Cosmic Dawn. However, it noted that through this method there can be significant amount loss if EoR covariance is misestimated. To obtain better models, we propose use kernel trained on {\tt GRIZZLY} simulations using Variational Auto-Encoder (VAE)...