[Étalonnage de LOFAR et lʼimagerie en champ large]
LOFAR est un instrument au design révolutionnaire qui opère à très basses fréquences () dans un domaine dʼénergie quasiment inexploré. Il est construit presque entièrement en software, et allie réseau phasé et interféromètre. Son utilisation conduira à des avancées scientifiques majeures, mais elle représente un défi technologique considérable. En effet, la sensibilité et le champ de vue de cet instrument étant accru de plusieurs ordres de grandeur par rapport à lʼancienne génération, des phénomènes subtils doivent être considérés. Dʼautre part, les nouvelles technologies utilisées comme les réseaux phasés entraînent des complications de taille. Dans le cadre du groupe de travail « relevés LOFAR » nous développons des procédures dʼétalonnage (ionosphère, lobes de station). Dans le cadre de ces problématiques, de nouvelles difficultés émergent, et les concepts de complexité algorithmique et de parallélisabilité deviennent une base de réflexion.
LOFAR is a revolutionary instrument, operating at low frequencies (). It will drive major breakthroughs in the area of observational cosmology, but its use requires the development of challenging techniques and algorithms. Since its field of view and sensitivity are increased by orders of magnitude as compared to the older generation of instruments, new technical problems have to be addressed. The LOFAR survey team is in charge of commissioning the first LOFAR data produced in the imager mode as part of building the imaging pipeline. We are developing algorithms to tackle the problems associated with calibration (ionosphere, beam, etc.) and wide-field imaging for the achievement of the deep extragalactic surveys. New types of problems arise in that context, and notions such as algorithmic complexity and parallelism become fundamental.
Mot clés : LOFAR, Interférométrie, Calibration, Imagerie
Cyril Tasse 1 ; Ger van Diepen 2 ; Sebastiaan van der Tol 3 ; Reinout J. van Weeren 3 ; Joris E. van Zwieten 3 ; Fabien Batejat 4 ; Sanjay Bhatnagar 5 ; Ilse van Bemmel 2 ; Laura Bîrzan 3 ; Annalisa Bonafede 6 ; John Conway 4 ; Chiara Ferrari 7 ; Francesco De Gasperin 8 ; Kumar Golap 5 ; George Heald 2 ; Neal Jackson 9 ; Giulia Macario 7 ; John McKean 2 ; Niruj Mohan 3 ; Emanuela Orrù 10 ; Roberto Pizzo 2 ; David Rafferty 3 ; Urvashi Rau 5 ; Huub Röttgering 3 ; Aleksandar Shulevski 10 ; on behalf of the LOFAR Collaboration
@article{CRPHYS_2012__13_1_28_0,
author = {Cyril Tasse and Ger van Diepen and Sebastiaan van der Tol and Reinout J. van Weeren and Joris E. van Zwieten and Fabien Batejat and Sanjay Bhatnagar and Ilse van Bemmel and Laura B{\^\i}rzan and Annalisa Bonafede and John Conway and Chiara Ferrari and Francesco De Gasperin and Kumar Golap and George Heald and Neal Jackson and Giulia Macario and John McKean and Niruj Mohan and Emanuela Orr\`u and Roberto Pizzo and David Rafferty and Urvashi Rau and Huub R\"ottgering and Aleksandar Shulevski and on behalf of the LOFAR Collaboration},
title = {LOFAR calibration and wide-field imaging},
journal = {Comptes Rendus. Physique},
pages = {28--32},
publisher = {Elsevier},
volume = {13},
number = {1},
year = {2012},
doi = {10.1016/j.crhy.2011.10.006},
language = {en},
}
TY - JOUR AU - Cyril Tasse AU - Ger van Diepen AU - Sebastiaan van der Tol AU - Reinout J. van Weeren AU - Joris E. van Zwieten AU - Fabien Batejat AU - Sanjay Bhatnagar AU - Ilse van Bemmel AU - Laura Bîrzan AU - Annalisa Bonafede AU - John Conway AU - Chiara Ferrari AU - Francesco De Gasperin AU - Kumar Golap AU - George Heald AU - Neal Jackson AU - Giulia Macario AU - John McKean AU - Niruj Mohan AU - Emanuela Orrù AU - Roberto Pizzo AU - David Rafferty AU - Urvashi Rau AU - Huub Röttgering AU - Aleksandar Shulevski AU - on behalf of the LOFAR Collaboration TI - LOFAR calibration and wide-field imaging JO - Comptes Rendus. Physique PY - 2012 SP - 28 EP - 32 VL - 13 IS - 1 PB - Elsevier DO - 10.1016/j.crhy.2011.10.006 LA - en ID - CRPHYS_2012__13_1_28_0 ER -
%0 Journal Article %A Cyril Tasse %A Ger van Diepen %A Sebastiaan van der Tol %A Reinout J. van Weeren %A Joris E. van Zwieten %A Fabien Batejat %A Sanjay Bhatnagar %A Ilse van Bemmel %A Laura Bîrzan %A Annalisa Bonafede %A John Conway %A Chiara Ferrari %A Francesco De Gasperin %A Kumar Golap %A George Heald %A Neal Jackson %A Giulia Macario %A John McKean %A Niruj Mohan %A Emanuela Orrù %A Roberto Pizzo %A David Rafferty %A Urvashi Rau %A Huub Röttgering %A Aleksandar Shulevski %A on behalf of the LOFAR Collaboration %T LOFAR calibration and wide-field imaging %J Comptes Rendus. Physique %D 2012 %P 28-32 %V 13 %N 1 %I Elsevier %R 10.1016/j.crhy.2011.10.006 %G en %F CRPHYS_2012__13_1_28_0
Cyril Tasse; Ger van Diepen; Sebastiaan van der Tol; Reinout J. van Weeren; Joris E. van Zwieten; Fabien Batejat; Sanjay Bhatnagar; Ilse van Bemmel; Laura Bîrzan; Annalisa Bonafede; John Conway; Chiara Ferrari; Francesco De Gasperin; Kumar Golap; George Heald; Neal Jackson; Giulia Macario; John McKean; Niruj Mohan; Emanuela Orrù; Roberto Pizzo; David Rafferty; Urvashi Rau; Huub Röttgering; Aleksandar Shulevski; on behalf of the LOFAR Collaboration. LOFAR calibration and wide-field imaging. Comptes Rendus. Physique, Volume 13 (2012) no. 1, pp. 28-32. doi : 10.1016/j.crhy.2011.10.006. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2011.10.006/
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