Exploring the primordial Universe with QUBIC
Jean-Christophe Hamilton,
Research Director at APC, Paris-Cité University, France
The School of Applied and Engineering Physics Seminar Series will occur on Thursday 15th May, at 15:30 at the UM6P campus (Ryad 5, 1st floor).
Abstract:
The Q & U Bolometric Interferometer for Cosmology (QUBIC) is a novel kind of CMB polarimeter, installed on the Puna plateau in Argentina and inaugurated at the end of 2022. QUBIC is optimized for the measurement of the B-mode polarization of the CMB, one of the major challenges of observational cosmology. The signal is expected to be of the order of a few tens of nK, prone to instrumental systematic effects and polluted by various astrophysical foregrounds which can only be controlled through multichroic observations. QUBIC is designed to address these observational issues with a novel approach, Bolometric Interferometry, that combines the advantages of interferometry in terms of control of instrumental systematic effects with those of bolometric detectors in terms of wide-band, background-limited sensitivity. The QUBIC synthesized beam has a frequency-dependent shape that results in the ability to produce maps of the CMB polarization in multiple sub-bands within the two physical bands of the instrument (150 and 220 GHz). Alternatively, QUBIC offers the possibility to perform component separation directly at the map-making stage, incorporating external information in a modular fashion. These features make QUBIC complementary to other instruments and makes it particularly well suited to characterize and remove Galactic foreground contamination.
The speaker will present the status of QUBIC, calibration results, the first observations of the Moon, as well as forecasts for B-modes detection. He will insist on the specific spectral-imaging feature that allows Bolometric Interferometry to identify foreground contamination in a unique manner, even in the pessimistic case of Galactic dust exhibiting frequency domain decorrelation.
Biography:
Jean Christophe Hamilton is Research Director at APC, Paris, France. After a PhD in Observational Cosmology in 1999 focused on searching type Ia supernovae with the EROS2 instrument, he did a post-doc at Centre National d’Études Spatiales (CNES) on the Planck ESA mission and on the Archeops instrument (balloon borne testbed for the Planck High Frequency Instrument) for which he lead the analysis leading to the first results. He was recruited at CNRS in 2001 pursuing his research with Planck and Archeops. In 2003, he started working on Ultra-High-Energy Cosmic Rays with the Pierre Auger Observatory, focusing on the search for elusive high-energy photons as well as on the search for anisotropies in the cosmic ray flux. He switched back to cosmology in 2006 when he joined the APC laboratory and started to develop the theory of Bolometric Interférometry, leading to the creation of the QUBIC collaboration in 2008 for which he has been the Spokesperson since then. During the years 2010-2015, he also worked on the study of large-scale-structure of the Universe with the SDSS-III/BOSS project where he developed alternative estimators for detecting the Baryonic Acoustic Oscillations (BAO) as well as a direct participation to the first detections of BAO with the Lyman-alpha forest using quasars at redshift 2.2. His research is now fully dedicated to QUBIC with a significant participation in the development of the data analysis algorithms and pipeline.
Localization: Ryad 5, 1st Floor.
Teams Link: School of Physics Seminar