Julien Girard

I am radio astronomer specialized in low & mid radio frequencies (LOFAR, NenuFAR, MeerKAT).I am associate professor at Université Paris Diderot (Paris 7) and I joined High Energy group at AIM.

 I am member of the MeerKAT/ThunderKAT collaboration and Co-I of the NenuFAR instrument (SKA pathfinder) in Observatoire Paris/Nançay.

I am member of the labex UnivEarthS Transient & Catastrophic Universe with Stéphane Corbel (AIM/LEPCHE) the COSMIC Project with Jean-Luc Starck (AIM/Cosmostat).

I am involved in various SKA projects with the Center for Radio Astronomy Techniques and Technologies with Oleg Sminov, at Rhodes University, Grahamstown.

Research Interests

Study of the X-ray / Radio correlations in microquasars (current thematic reconversion)

Instrumentation &Signal Processing for ground-based radio interferometry

Sparse reconstruction of interferometric data

Application of Sparse theorems to LOFAR/MeerKAT/SKA radio interferometry imaging
Development of a 3-D time-agile and multi-channel Sparse imager for the search of radio transients
Application to Weak lensing studies in preparation for the SKA

Preparation of NenuFAR (SKA pathfinder)

Commissioning and data model and standardisation
Incremental development and scientific exploitation

Other research topics

(Exo)planetary radio emissions at low frequencies

Jovian non-thermal emissions (radiobursts in the decameter range and radiation belts in the decimeter) with LOFAR
Abundance of water in Saturn deep atmosphere (kbar level) with LOFAR
Detection and study of Saturn Electrostatic Discharges (SED) with LOFAR
Search and characterization of exoplanetary transients radio signals with LOFAR

Phased array interferometer optimization

Small antenna array beam optimization
Interferometers/phased configurations
Graph theory approach for the Cable/Trench minimization problem (CTP)

Antenna design and Electromagnetic Simulations
Numerical Electromagnetic simulations (NEC) for ground-based instruments (LOFAR, NenuFAR) and space-borne instruments (NOIRE Project CNES/OP)

Refereed Articles

K. Iheanetu, J. N. Girard, O. Smirnov, K. M. B. Asad, M. de Villiers, K. Thorat, S. Makhathini, R. A. Perley. Primary beam effects of radio astronomy antennas: I. Modelling the Karl G. Jansky Very Large Array (VLA) L-band beam using holography, accepted in MNRAS, March 2019 MNRAS arxiv
Philippe Zarka, Di Li, Jean-Mathias Grießmeier, Laurent Lamy, Julien N. Girard, Sébastien L. G. Hess, T. Joseph W. Lazio and Gregg Hallinan. Detecting exoplanets with FAST? RAA 2019 Vol. 19 No. 2, 23, 2019 Link
G. Molenaar, S. Makhathini, J. N. Girard, and O. Smirnov. Kliko-The scientific compute container format. Astronomy and Computing, 25:1–9, October 2018 Link
K. Zyma, J. N. Girard, E. Landquist, G. Schaper and F. J. Vasko, Formulating and solving a radio astronomy antenna connection problem as a generalized cable-trench problem: an empirical study, International Transactions in Operational Research, 1475-3995, 2016 Link
J. N. Girard, P. Zarka, C. Tasse, S. Hess, I. de Pater, D. Santos-Costa, Q. Nenon, A. Sicard, S. Bourdarie and 64 coauthors. Imaging Jupiter's radiation belts down to 127 MHz with LOFAR. A&A, 587:A3, March 2016 Link
J.N. Girard, H. Garsden, J.L. Starck, S. Corbel, A. Woiselle, C. Tasse, J.P. McKean and J. Bobin, Sparse representations and convex optimization as tools for LOFAR radio interferometric imaging, JINST, 2015, 10 C08013, Link
Garsden H., Girard J. N., Starck J. L., Corbel S., Tasse C., Woiselle A., J. P. Mckean et al. LOFAR Sparse Image Reconstruction, Astron. Astrophys., 575, A90, 2015. Link
Zarka P., Bougeret J.-L., Briand C., Cecconi B., Falcke H., Girard J. N. et al., Planetary and exoplanetary low frequency radio observations from the Moon, Planet. Space Sci., Vol. 74, Issue 1, Pages 156-166, 2012.
Girard J. N., Zarka P., Tagger M. et al., Antenna design and distribution for a LOFAR Super Station, CR Physique Académie des Sciences, Volume 13, Issue 1, Pages 33-37, 2012.
Grießmeier J.-M., Zarka P., Girard J. N., Tagger M. et al., Observation of planetary radio emissions using large arrays, Radio Science, Volume 46, RS0F09, 9 PP., 2011.

Conference Proceedings (BEING UPDATED)

J. N. Girard, K. Iheanetu, O. M. Smirnov, K. M. B. Asad, M. de Villiers, K. Thorat, S. Makhathini and R. Perley, Accurate beam modeling using sparse representations of VLA holography measurements, SF2A-2018: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics Link
M. Jiang, J. N. Girard, J. L. Starck, S. Corbel, and C. Tasse. Compressed sensing and radio interferometry. In Signal Processing Conference (EUSIPCO), 2015 23rd European, pages 1646-1650, August 2015 IEEE
M. Jiang, J. N. Girard, J.-L. Starck, S. Corbel, and C. Tasse. Interferometric Radio Transient Reconstruction in Compressed Sensing Framework. In F. Martins, S. Boissier, V. Buat, L. Cambresy, and P. Petit, editors,
SF2A-2015: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics. Eds.:
F. Martins, S. Boissier, V. Buat, L. Cambrésy, P. Petit, pp.231-236, pages 231-236, December 2015 (ADS)
J. N. Girard, P. Zarka, C. Tasse, and S. Hess, Jupiter synchrotron imaging with LOFAR, SF2A-2012 : Proc. Annual meeting of the French Society of Astronomy and Astrophysics, Eds. : S. Boissier, P. de Laverny, N. Nardetto, R. Samadi, D. Valls-Gabaud and H. Wozniak, Nice, France, pp.681-686, 2012
P., Zarka, J. N., Girard, M. Tagger, L. Denis, and the LSS team, LSS/NenuFAR : The LOFAR Super Station project in Nançay, SF2A-2012 : Proc. Annual meeting of the French Society of Astronomy and Astrophysics, Eds. : S. Boissier, P. de Laverny, N. Nardetto, R. Samadi, D. Valls-Gabaud and H. Wozniak, Nice, France, pp.687-694, 2012
Girard J. N., Zarka P., Tagger M., et al., Antenna Design and Distribution for a LOFAR Super Station in Nançay, in "Planetary Radio Emissions VII", H. O. Rucker et al. eds., Austrian Acad. Sci. Press, Vienna, Austria, p. 495-503, 2011 (refereed)
Zarka P., Girard, J. N., J.-M. Grießmeier, et al., Planetary and exoplanetary studies with the giant radio telescope LOFAR, in "Planetary Radio Emissions VII", H. O. Rucker et al. eds., Austrian Acad. Sci. Press, Vienna, Austria, p. 505, 2011 (refereed)
J.-M. Grießmeier, P. Zarka, A. Konovalenko, G. Fischer, V. Zakharenko, B. W. Stappers, J. N. Girard, B. Ryabov, D. Vavriv, V. Ryabov, and H. O. Rucker, Ground-based study of Saturn lightning, in "Planetary Radio Emissions VII", H. O. Rucker et al. eds., Austrian Acad. Sci. Press, Vienna, Austria, pp. 145-154, 2011 (refereed)
Grießmeier, J.-M., Zarka, P., Girard, J. N., Ter Veen, S. ,Falcke, H., Ground-based study of solar system planetary lightning, in proceedings of 3rd International SKA Forum 2010", PoS(ISKAF2010)022, 2010
P. Zarka, J.-M. Grießmeier, J. N. Girard, S. Hess, B. Cecconi, L. Denis, et al., Etudes Planetaires et Exoplanetaires avec le Radiotelescope LOFAR, Programme National de Planetologie, Colloque Quadriennal de Bilan et Prospective, IUEM Plouzané, France, 13-15-9-2010

Conferences (full list here) (BEING UPDATED)

July 2010: XL^th YERAC - Young European Radio Astronomers Conference, Alcala de Henares, Espagne (talk)
September 2010: 7^th International Workshop on Planetary, Solar and Heliospheric Radio Emissions, Graz, Autriche (poster)
December 2010: 1st France-Ukraine PICS program meeting (LOC/SOC), Meudon, France (talk)
March 2011: Journées scientiques de l'URSI-France, Les radiotélescopes du futur : technologies et avancées scientifiques, Paris, France (URSI-France award of the best student contribution) (talk)
September 2011: TKP first results with LOFAR, Dalfsen, The Netherlands (talk & poster)
December 2011: LOFAR TKP meeting, Meudon, France (talk)
December 2011: 2^nd France-Ukraine PICS program meeting, Meudon, France (talk)
August 2011: URSI General Assembly, Istanbul, Turkey (poster)
March 2012: UK-Germany National Astronomy Meeting (NAM), Manchester, UK (poster)
June 2012: Journées de la Société Française d'Astronomie et d'Astrophysique, Nice, France (talk)
June 2013: Semaine de l'Astrophysique Française de la SF2A, Montpellier, France (talk)
June 2013: AOGS, Brisbane, Australia (invited talk)
July 2013: Magnetospheres of Outer Planets, Athens, Greece (talk)
January 2014: LOFAR TKP meeting, Amsterdam, the Netherlands (2 talks)
February 2014: SKA-LOFAR Radio Days, Paris, France (talk)
April 2014: EGU General Assembly, Vienne, Austria (invited talk)
July 2014: 2^nd International Summer School on : INtelligent Signal Processing for FrontIEr Research and Industry (INFIERI 2014), Paris, France (lecture)
September 2014: EPSC, Cascais, Portugal (invited talk)
September 2014: Radio Weak Lensing, Manchester, UK (talk)
October 2014: From Gaia to Cosmos: observation and modelling, Florence, Italy (poster)
2015 PhySIS kick-off meeting, Saclay, France (talk)
May 2015: Magnetospheres of Outer Planets, Atlanta, USA (invited talk)
November 2015: SKA Bursary conference, Stellenbosch, South Africa (poster)
2016 to fill
2017 to fill
2018 (being updated)

Workshops

September 2009: Towards third generation calibration in radio astronomy - MCCT SKADS/MeqTrees Workshop, USN, Nançay, France
December 2009: 6^th Pulsar busy week, ASTRON, Dwingeloo, The Netherlands
April 2010: Transient busy week, ASTRON, Dwingeloo, The Netherlands
October 2010: 2^nd LOFAR Data Processing School, ASTRON, Dwingeloo, The Netherlands
December 2010: LOFAR Programming Tutorial, ASTRON, Dwingeloo, The Netherlands
Juillet 2011: LOFAR Programming Tutorial, ASTRON, Dwingeloo, The Netherlands
May 2012: Long Baselines busy week, MPIfRA, Bonn, Germany
March 2013: LOFAR Dalfsen II : Collaboration Science Workshop, Dalfsen, the Netherlands (talk)
January 2014: NenuFAR workshop : the science of NenuFAR, Paris, France (talk)
May 2014: 14^th NRAO synthesis imaging workshop, Socorro, United States
December 2014: LOFAR Imaging busy week, Dwingeloo, the Netherlands
March 2015:Next-Generation Radio Interferometric Imaging for the SKA 2015, Delheim, South Africa (here)
March 2015: Joint NL-SA radio continuum workshop
TO BE UPDATED

Conference & School organisation

2015: International Young Astronomer School, ED127, Sèvres, France
2014: SKA-LOFAR radio days (SOC/LOC), Paris, France
2014: NenuFAR workshop: the science of NenuFAR, Paris, France
2011: 3rd LOFAR TKP meeting (LOC), Meudon, France
2011: 2nd France-Ukraine PICS program meeting (SOC/LOC), Meudon, France
2010: 1st France-Ukraine PICS program meeting (SOC/LOC), Meudon, France
TO BE UPDATED

Contact Information
E-mail:	julien.girard [at] obspm [dot] fr
Phone:	+33 (0)1 45 07 71 46
Affiliation:	*LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris Cité, 5 place Jules Janssen, 92195 Meudon, France*

Julien Girard

ASSOCIATE PROFESSOR

Research Interests

Cursus

Software (being updated)

Publications (being updated)

Contributions to conference/workshops