Mapping cosmic matter distribution in radio, through the observation of 21 cm radiation of neutral atomic hydrogen is a complementary method to optical surveys to study Large Scale Structures (LSS) and more specifically, the Baryon Acoustic Oscillations (BAO). An R&D program for 21 cm cosmological surveys is being carried out by LAL (CNRS/IN2P3), IRFU (CEA) and several Observatoire de Paris laboratories: GEPI, LESIA and the Nançay radio astronomy observatory (USN). The BAORadio R&D effort is part of an international effort, bringing together scientists from France, USA, Canada and China. The NAOC (National Astronomical Observatories, Chinese Academy of Sciences), Carnegie Mellon University (CMU), University of Wisconsin (UW), Fermilab and CITA are among the institutes contributing currently to the project.
The following sub-projects are currently part of BAORadio in France:
- Development of a set of electronic modules suited to 21 cm digital interferometry (BAORadio electronic system)
- Development of the acquisition and processing software suit, including a software correlator (BAORadio / TAcq package)
- FAN, which is a focal plane phased array receiver system for the Nançay radio telescope (NRT), equipped with the BAORadio electronic and acquisition system
- PAON, which is a small testbed for dense array interferometers using small (D ~ 5 m) dishes with wide band receivers at Nançay
- Wide band observations using the NRT and the BAORadio electronic system or the WIBAR receiver system, aiming at the detection of HI in clusters in the redshift range z ~ 0.1-0.2 (Amas@Nançay)