Welcome!

My name is Gabriel Jung and I am a postdoc at the Institut d’Astrophysique Spatiale in Orsay (France).

My research interests lie in the field of cosmology, focusing on the statistical analysis of cosmological data.

I am currently part of the LOCALIZATION team, where I study the impact on the Cosmic Microwave Background (CMB) anisotropies of the Large Scale Structure (LSS) in our local Universe.

Most of my previous research works are related to cosmological non-Gaussianity (NG). Precise measurements are necessary to understand the details of non-linear structure formation by gravitational instability, and a detection of primordial NG would constrain significantly the physics at play in the very early universe.

• Large-scale structure (LSS): How much information about primordial NG can we really expect from upcoming galaxy surveys? To answer this question, I am working on simulation-based approaches for the statistical analysis of galaxy density fields in the gravitational non-linear regime. Our first results are based on the QUIJOTE-PNG set of simulations, and combine the power spectrum and modal bispectrum observables to estimate jointly $\Lambda$CDM cosmological parameters and primordial NG amplitudes ($f_\mathrm{NL}$) from the matter or halo fields.
• Cosmic Microwave Background (CMB): I developed the integrated angular bispectrum estimator on the celestial sphere, a practical method to study the squeezed limit of the bispectrum using only power spectra. This includes an analysis of the latest Planck observational data. The method was then applied in the weak lensing context (simulations), to study the convergence field.
• Galactic CMB foregrounds: I studied the non-Gaussian properties of galactic foregrounds (dust, synchrotron, free-free, AME) using the binned bispectrum estimator and checked the efficiency of cleaning procedures at the non-Gaussian level in Planck data.
• Multiple-field inflation (theory): I investigated the NG produced in two-field inflation, both analytically and numerically, to better understand what regions of inflation model space have been ruled out by the absence of detection of primordial NG in Planck data.