Radio observations

Radio emissions are the signature of energetic electron beams propagating towards the IPM or falling back to the Sun (Fast CMEs, Strong Flares). Spectral data give access to several coronal parameters (coronal temperature, electron beam velocity, magnetic field strength, turbulence level …, etc.), constraining the simulation/modeling. Emission source locations (imaging) indicate where acceleration processes take place.
This Website provides access to visualization tools from NenuFAR, NDA, and NRH.

NenuFAR is a very large radio telescope working in the frequency range 10-85MHz (Zarka 2015, 2020, Bondonneau 2021). It is located at the Nançay Radio Observatory in Sologne (France). It can work as a standalone instrument or be connected to the international LOFAR network. Solar physics is one of the many topics tackled by the instrument (Briand et al. 2022). NenuFAR observes during dedicated campaigns and for Target of opportunity, thus on an irregular schedule.
NenuFAR provides Time-Frequency spectra and images.

NDA(Nançay Decameter Array) has been operating at the Nançay Radio Observatory in Sologne (France) for over forty years (Lamy et al. 2017). Several observing modes correspond to different time and spectral resolutions (see Table 1). NDA is mainly dedicated to the Sun and Jupiter: NDA operates daily on the two targets for a large part of the year and on Jupiter only when the planet is visible during the day. NDA provides only Time-Frequency spectra

NDA Observing modes
The first column gives the mode names together with the date of commissioning; The second column indicates the availability of the auto-correlation from the Right (R) or Left (L) sub-array, or the cross-correlation (LR); The third column indicates the filtered and unfiltered channels available; The fourth column presents the spectral range; the fifth column displays the time and spectral resolution; The sixth column shows the data volume for 8hours of observation.
@Lamy et al. 2017

LOFAR is a radio interferometer comprising 52 stations, 38 in the Netherlands (including the core) and 14 spread over Europe (including one at the Nançay Radio Observatory ). It observes in two frequency bands: 10 to 90MHz (LBA) and 110 to 250 MHz (HBA). It has been operating since 2010. It is a versatile instrument that tackles several astronomical topics, including solar physics (Breitling et al., 2015). LOFAR ERIC (European Research Infrastructure Consortium) was officially established at the end of 2023 with the Netherlands as the hosting country. LOFAR provides Time-Frequency spectra and images.

The following list gathers the interfaces for visualization or data downloading:

  • NenuFAR: a visualization tool developed in the frame of the SOLER Horizon EU-program, that enables to identify the days when NenuFAR was observing the Sun, and visualize a quick-look of the full observations and zoom-in views over 1min of the four Stokes parameters (polarimetric data). When available, pictures and movies can also be visualized. The volume of NenuFAR data does not allow for easy download. If you want to analyze the data, please contact the KP11 leaders.
  • From the VESPA VO interface, quick-looks and data are accessible for NDA, Orfees, and NRH
  • NDA Routine: display the NDA-Routine mode data;
  • NDA New Routine: Direct access for data downloading of the NDA-New Routine mode data;
  • NDA Mefisto: direct access for data downloading of Mefisto-NDA mode data;
  • Solar Data Base@Nancçay: for data downloading from NDA (routine only), Orfees, and NRH instruments;
  • BASS200: access to quick-looks from NRH and colored routine data from NDA. Optical observations are also available, providing a more visual solar context.
    – Secchirh: Ground-based and space instruments

Bibliography

  • Bondonneau L. et al. (2021), "Pulsars with NenuFAR: Backend and pipelines",
    Astronomy & Astrophysics, Volume 652, id.A34, 12 pp., DOI:10.1051/0004-6361/202039339
  • Breitling F. et al. (2015),"The LOFAR Solar Imaging Pipeline and the LOFAR Solar Data Center", Astronomy and Computing, Vol. 13, Pages 99-107, DOI: 10.1016/j.ascom.2015.08.001
  • Briand, C. et al. (2022), "NenuFAR Performance for Solar Radio Observations", URSI Radio Science Letters, vol. 4, id. 17, DOI:10.46620/22-0017
  • Lamy L. et al. (2017), "1977-2017: 40 years of decametric observations of Jupiter and the Sun with the Nançay Decameter Array", Planetary Radio Emissions VIII, Proceedings of the 8th International Workshop held at Seggauberg, Austria, October 25-27, 2016. Edited by G. Fischer, G. Mann, M. Panchenko, and P. Zarka. Austrian Academy of Sciences Press, Vienna, 2017, p. 455-466, DOI: 10.1553/PRE8s455; 10.48550/arXiv.1709.03821
  • Zarka P. et al. (2020), "The low-frequency radio telescope NenuFAR", Session J01 « New Telescopes on the Frontier », URSI GASS, Rome, 29/8-5/9/2020
  • Zarka P. et al. (2015), "NenuFAR: Instrument Description and Science Case", International Conference on Antenna Theory and Techniques (ICATT), Kharkiv, Ukraine, pp. 13-18, 21-24 April, 2015.