Dr Philippe ZARKA (Observatoire de Paris, MEUDON)
While the construcion of NenuFAR is based on the design study carried during an ANR project 2009-2013 and the thesis of J. Girard (2013), it is also characterized by an agile management that allows evolution of the details of the concept at all stages. Recent developments include a few additional mini-arrays of 19 antennas located far from the compact (400m diameter) core, up to ~2 km...
Prof. Leon Koopmans (Kapteyn Astronomical Institute)
I will discuss the technical and processing requirements necessary for a successful detection of the redshifted 21-cm signal of neutral hydrogen during the Cosmic Dawn with NenuFar, as well as other challenges that need to be overcome such as low-frequency wide-field ionospheric scintillation.
Prof. Benjamin Wandelt (IAP, UPMC)
We present a new Bayesian semi-blind approach for foreground removal in observations of the 21-cm signal with interferometers. The technique, which we call HIEMICA (HI Expectation-Maximization Independent Component Analysis), is an extension of the Independent Component Analysis (ICA) technique developed for two-dimensional (2D) CMB maps to three-dimensional (3D) 21-cm cosmological signals...
Anastasia Fialkov (ENS)
The redshifted 21-cm signal of neutral hydrogen, which at every cosmic epoch is strongly correlated to the state of the intergalactic medium and the intensity of radiative backgrounds, is expected to be a unique probe of the Universe at early times. In this talk I will, first, set up the stage, discussing the properties of the signal from the key cosmological epochs, which includes the Dark...
Dr benoit semelin (LERMA)
Detecting the 21 cm signal from the EoR not in absorption/emission against the CMB but in absorption against a bright background radio sources (radio-loud QSO) removes many observational difficulties such as foreground removal. It has the potential to probe much smaller scales than 21 cm tomography. Consequently it requires a more detailed modeling. I will present simulation results that...
Dr Cyril Tasse (Observatoire de Paris)
I will present the current state of calibration and imaging techniques for LOFAR, and in particular for the extragalactic surveys Key Science Project. I will focus the discourse on the algorithms relevent to NenuFAR Dark Ages project.
2. Visibility based angular power spectrum estimation in low frequency radio interferometric observations
Dr Abhik Ghosh (Kapteyn Astronomical Institute)
We present two estimators to quantify the angular power spectrum of the sky signal directly from the visibilities measured in radio interferometric observations. This is relevant for both the foregrounds and the cosmological 21-cm signal buried therein. The discussion here is restricted to the Galactic synchrotron radiation, the most dominant foreground component after point source removal....