LOFAR facet calibration
R. J. van Weeren,Wendy L. Williams,Wendy L. Williams,Wendy L. Williams,Martin J. Hardcastle,Timothy W. Shimwell,D. A. Rafferty,J. Sabater,George Heald,S. S. Sridhar,S. S. Sridhar,T. J. Dijkema,Gianfranco Brunetti,Marcus Brüggen,Felipe Andrade-Santos,Georgiana A. Ogrean,Huub Röttgering,William A. Dawson,William R. Forman,F. de Gasperin,Christine Jones,George K. Miley,Lawrence Rudnick,Craig L. Sarazin,Annalisa Bonafede,Philip Best,Laura Birzan,Rossella Cassano,Krzysztof T. Chyzy,Judith H. Croston,Torsten A. Ensslin,Chiara Ferrari,Matthias Hoeft,Cathy Horellou,Matt J. Jarvis,Ralph P. Kraft,M. Mevius,Huib Intema,Huib Intema,S. S. Murray,S. S. Murray,Emanuela Orru,R. Pizzo,Aurora Simionescu,Andra Stroe,S. van der Tol,Glenn J. White,Glenn J. White +47 more
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In this paper, a new calibration scheme, which is named facet calibration, was proposed to obtain deep high-resolution LOFAR High Band Antenna images using the Dutch part of the array.Abstract:
LOFAR, the Low-Frequency Array, is a powerful new radio telescope operating between 10 and 240 MHz. LOFAR allows detailed sensitive high-resolution studies of the low-frequency radio sky. At the same time LOFAR also provides excellent short baseline coverage to map diffuse extended emission. However, producing high-quality deep images is challenging due to the presence of direction dependent calibration errors, caused by imperfect knowledge of the station beam shapes and the ionosphere. Furthermore, the large data volume and presence of station clock errors present additional difficulties. In this paper we present a new calibration scheme, which we name facet calibration, to obtain deep high-resolution LOFAR High Band Antenna images using the Dutch part of the array. This scheme solves and corrects the direction dependent errors in a number of facets that cover the observed field of view. Facet calibration provides close to thermal noise limited images for a typical 8 hr observing run at $\sim$ 5arcsec resolution, meeting the specifications of the LOFAR Tier-1 northern survey.read more
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Journal ArticleDOI
The LOFAR Two-metre Sky Survey. I. Survey description and preliminary data release
Timothy W. Shimwell,Huub Röttgering,Philip Best,Wendy L. Williams,T. J. Dijkema,F. de Gasperin,Martin J. Hardcastle,George Heald,D. N. Hoang,A. Horneffer,Huib Intema,Elizabeth K. Mahony,Elizabeth K. Mahony,Subhash C. Mandal,A. P. Mechev,Leah K. Morabito,J. B. R. Oonk,J. B. R. Oonk,D. A. Rafferty,E. Retana-Montenegro,J. Sabater,Cyril Tasse,Cyril Tasse,R. J. van Weeren,Marcus Brüggen,Gianfranco Brunetti,Krzysztof T. Chyzy,John Conway,Marijke Haverkorn,Neal Jackson,Matt J. Jarvis,Matt J. Jarvis,John McKean,George K. Miley,Raffaella Morganti,Raffaella Morganti,Glenn J. White,Glenn J. White,Michael W. Wise,Michael W. Wise,I. van Bemmel,Rainer Beck,Marisa Brienza,Annalisa Bonafede,G. Calistro Rivera,Rossella Cassano,A. O. Clarke,D. Cseh,Adam Deller,A. Drabent,W. van Driel,W. van Driel,D. Engels,Heino Falcke,Heino Falcke,Chiara Ferrari,S. Fröhlich,M. A. Garrett,Jeremy J. Harwood,Volker Heesen,Matthias Hoeft,Cathy Horellou,Frank P. Israel,Anna D. Kapińska,Anna D. Kapińska,Magdalena Kunert-Bajraszewska,D. J. McKay,D. J. McKay,N. R. Mohan,Emanuela Orru,R. Pizzo,R. Pizzo,Isabella Prandoni,Dominik J. Schwarz,Aleksandar Shulevski,M. Sipior,Daniel J. Smith,S. S. Sridhar,S. S. Sridhar,Matthias Steinmetz,Andra Stroe,Eskil Varenius,P. van der Werf,J. A. Zensus,Jonathan T. L. Zwart,Jonathan T. L. Zwart +85 more
TL;DR: The LOFAR Two-metre Sky Survey (LoTSS) as mentioned in this paper is a deep 120-168 MHz imaging survey that will eventually cover the entire northern sky, where each of the 3170 pointings will be observed for 8 h, which, at most declinations, is sufficient to produce ~5? resolution images with a sensitivity of ~100?Jy/beam and accomplish the main scientific aims of the survey, which are to explore the formation and evolution of massive black holes, galaxies, clusters of galaxies and large-scale structure.
Journal ArticleDOI
The GMRT 150 MHz All-sky Radio Survey: First Alternative Data Release TGSS ADR1
Hubertus Intema,Hubertus Intema,Preshanth Jagannathan,Preshanth Jagannathan,Kunal Mooley,Dale A. Frail +5 more
TL;DR: The first full release of a survey of the 150 MHz radio sky, observed with the giant metrewave radio telescope between April 2010 and March 2012 as part of the TGSS project is presented in this article.
Journal ArticleDOI
LOFAR 150-MHz observations of the Boötes field: catalogue and source counts
Wendy L. Williams,Wendy L. Williams,Wendy L. Williams,R. J. van Weeren,Huub Röttgering,Philip Best,T. J. Dijkema,F. de Gasperin,Martin J. Hardcastle,George Heald,George Heald,Isabella Prandoni,J. Sabater,Timothy W. Shimwell,C. Tasse,I. van Bemmel,Marcus Brüggen,Gianfranco Brunetti,John Conway,Torsten A. Enßlin,D. Engels,Heino Falcke,Heino Falcke,Chiara Ferrari,Marijke Haverkorn,Marijke Haverkorn,N. J. Jackson,Matt J. Jarvis,Anna D. Kapińska,Anna D. Kapińska,Elizabeth K. Mahony,George K. Miley,Leah K. Morabito,R. Morganti,R. Morganti,Emanuela Orrú,E. Retana-Montenegro,S. S. Sridhar,S. S. Sridhar,M. C. Toribio,Glenn J. White,Glenn J. White,Michael W. Wise,Michael W. Wise,Jonathan T. L. Zwart,Jonathan T. L. Zwart +45 more
TL;DR: In this paper, the authors presented the first wide area (19 deg(2)), deep (a parts per thousand 120-150 mu Jy beam(-1)), high-resolution (5.6 x 7.4 arcsec) LOFAR High Band Antenna image of the Bootes field made at 130-169 MHz.
Dataset
LOFAR Two-metre Sky Survey
Timothy W. Shimwell,Huub Röttgering,P. N. Best,Wendy L. Williams,T. J. Dijkema,F. de Gasperin,Martin J. Hardcastle,George Heald,D. N. Hoang,A. Horneffer,Huib Intema,Elizabeth K. Mahony,S. Mandal,A. P. Mechev,Leah K. Morabito,J. B. R. Oonk,D. A. Rafferty,E. Retana-Montenegro,J. Sabater,C. Tasse,R. J. van Weeren,Marcus Brüggen,Gianfranco Brunetti,Krzysztof T. Chyzy,John Conway,Marijke Haverkorn,Neal Jackson,Matt J. Jarvis,John McKean,George K. Miley,Raffaella Morganti,Glenn J. White,Michael W. Wise,I. M. van Bemmel,Ron Beck,M. Brienza,Annalisa Bonafede,G. Calistro Rivera,Rossella Cassano,A. O. Clarke,D. Cseh,Adam Deller,A. Drabent,W. van Driel,D. Engels,Heino Falcke,C. Ferrari,S. Fröhlich,Garrett,Jeremy J. Harwood,Volker Heesen,Matthias Hoeft,Cathy Horellou,Frank P. Israel,Anna D. Kapińska,Magdalena Kunert-Bajraszewska,D. J. McKay,N. R. Mohan,Emanuela Orrú,Roberto Pizzo,Isabella Prandoni,Dominik J. Schwarz,Aleksandar Shulevski,M. Sipior,Daniel J. Smith,S. S. Sridhar,Matthias Steinmetz,Andra Stroe,Eskil Varenius,P. van der Werf,J. A. Zensus,Jonathan T. L. Zwart +71 more
TL;DR: The LOFAR Two-metre Sky Survey (LoTSS) is an ongoing sensitive, high-resolution 120-168 MHz survey of the entire northern sky for which observations are now 20% complete as discussed by the authors.
Journal ArticleDOI
An optimized algorithm for multiscale wideband deconvolution of radio astronomical images
A. R. Offringa,Oleg Smirnov +1 more
TL;DR: An improved multi-scale deconvolution algorithm that can also be used in multi-frequency mode, and a new scale-bias function for use inMulti-scale cleaning.
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Related Papers (5)
LOFAR facet calibration
R. J. van Weeren,Wendy L. Williams,Wendy L. Williams,Wendy L. Williams,Martin J. Hardcastle,Timothy W. Shimwell,D. A. Rafferty,J. Sabater,George Heald,S. S. Sridhar,S. S. Sridhar,T. J. Dijkema,Gianfranco Brunetti,Marcus Brüggen,Felipe Andrade-Santos,Georgiana A. Ogrean,Huub Röttgering,William A. Dawson,William R. Forman,F. de Gasperin,Christine Jones,George K. Miley,Lawrence Rudnick,Craig L. Sarazin,Annalisa Bonafede,Philip Best,Laura Birzan,Rossella Cassano,Krzysztof T. Chyzy,Judith H. Croston,Torsten A. Ensslin,Chiara Ferrari,Matthias Hoeft,Cathy Horellou,Matt J. Jarvis,Ralph P. Kraft,M. Mevius,Huib Intema,Huib Intema,S. S. Murray,S. S. Murray,Emanuela Orru,R. Pizzo,Aurora Simionescu,Andra Stroe,S. van der Tol,Glenn J. White,Glenn J. White +47 more
The LOFAR Two Meter Sky Survey: Deep Fields, I -- Direction-dependent calibration and imaging
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Systematic effects in LOFAR data: A unified calibration strategy
F. de Gasperin,F. de Gasperin,T. J. Dijkema,A. Drabent,M. Mevius,D. A. Rafferty,R. J. van Weeren,Marcus Brüggen,Joseph R. Callingham,K. L. Emig,George Heald,Huib Intema,Leah K. Morabito,A. R. Offringa,R. Oonk,R. Oonk,Emanuela Orru,Huub Röttgering,J. Sabater,Timothy W. Shimwell,Timothy W. Shimwell,Aleksandar Shulevski,Wendy L. Williams +22 more