Research &  publications

Fig. NeuFAR- SKA pathfinder

2- Commissioning of SKA Pathfinder radio telescopes (LOFAR, NenuFAR, GMRT)

I have extensively participated in the Commissioning activities (such as data quality checking, imaging techniques at very low frequencies, data validation, developing observation tools, and producing reports, and memos) of the SKA Pathfinder Telescopes such as LOFAR and NenuFAR. I have also trained LOFAR and GMRT first-time users with data validation and analysis.

i)- Compact Array Image Sensitivity Calculator

The Compact array image sensitivity calculator is adapted from the LOFAR image sensitivity calculator (G. Heald et al.). Here is the link for the Compact Array Image Sensitivity Calculator:

Please note that the calculator is regularly being updated to include new features. It gives values for theoretical noise from a Compact array with a 3 km longest baseline, similar to LOFAR core stations or NenuFAR core + remote stations using Condon et al. 2002

The theoretically expected Image sensitivity values using baselines & core+remote stations for the correlator data and based on the LOFAR image sensitivity calculator are also provided at the end of the computation. However, please note that the noise measured in the confusion-limited images is typically 4-5 times higher than the theoretical noise and affected by several systematics. The users are recommended to use the theoretical values as a reference for the highest achievable sensitivity in images not dominated by confusion limit.

ii)-Cluster of galaxies and AGNs NenuFAR  Survey (CANS)- Key science program- PI- M. Pommier

Non-thermal emission from extragalactic sources (like radio galaxies and clusters of galaxies) dominate the low-frequency sky and tend to show extended morphology up to a few arc-minutes angular size and steep (alpha ~ -1.0) or ultra-steep (alpha < -1.5) spectral response that emits prominently at lower frequencies (in the MHz-range). In the Cluster of galaxies and AGNs NenuFAR Survey (CANS)- key science project we propose to carry out a survey on galaxy clusters and AGNs to highlight the imaging capability of NenuFAR - the French SKA-Pathfinder and to probe the extragalactic sky with twice the sensitivity of LOFAR for short baselines over a wide range of observing frequencies. The Key Science Program with the NenuFAR during the early science phase is proposed over a period of 2 years (January 2020-December 2021), in order to detect the faint diffuse structures from extragalactic sources. 

iii)- NenuFAR Commissioning results

The first  NenuFAR images  at 50 MHz  of A-Team sources  (mostly giant radio galaxies and SNRs) and LOFAR flux calibrators (Radio galaxies and quasars) presented at EWASS 2019- SKA session are available here

For detailed reports refer link-:

1-Pommier, M.,P. Zarka et al. NenuFAR commissioning observations on LOFAR calibrators; 2019

2-Pommier, M., et al. NenuFAR Image Sensitivity calculation; 2019

3-Pommier, M.,P. Zarka et al. NenuFAR commissioning deep observations (in narrow band mode) on A-Team source Cyg A and systematic effects, 2019

4-M.Pommier, P. Zarka et al. NenuFAR Imager mode commissioning and calibration (in the narrow band) with ATeam observations, 2019

5-M.Pommier, P. Zarka et al. NenuFAR Beam former mode commissioning and calibration using Laboratory Measurement, 2018. 

Fig. LOFAR-Core stations in the Netherlands and GMRT array, Pune, India