LOFAR FACET CALIBRATION
- Creators
- Weeren, R.
- Williams, W.
- Hardcastle, M.
- Shimwell, T.
- Rafferty, D.
- Sabater, J.
- Heald, G.
- Sridhar, S.
- Dijkema, T.
- Brunetti, G.
- Brüggen, M.
- Andrade-Santos, F.
- Ogrean, G.
- Röttgering, H.
- Dawson, W.
- Forman, W.
- Gasperin, F. De
- Jones, C.
- Miley, G.
- Rudnick, L.
- Sarazin, C.
- Bonafede, A.
- Best, P.
- Bîrzan, L.
- Cassano, R.
- Chyży, K.
- Croston, J.
- Ensslin, T.
- Ferrari, C.
- Hoeft, M.
- Horellou, C.
- Jarvis, M.
- Kraft, R.
- Mevius, M.
- Intema, H.
- Murray, S.
- Orrú, E.
- Pizzo, R.
- Simionescu, A.
- Stroe, A.
- Tol, S. van Der
- White, G.
- Others:
- Harvard-Smithsonian Center for Astrophysics (CfA) ; Harvard University [Cambridge]-Smithsonian Institution
- Leiden University
- Netherlands Institute for Radio Astronomy (ASTRON)
- University of Hertfordshire [Hatfield] (UH)
- Hamburger Sternwarte/Hamburg Observatory ; Universität Hamburg (UHH)
- Institute for Astronomy [Edinburgh] (IfA) ; University of Edinburgh
- Kapteyn Astronomical Institute [Groningen] ; University of Groningen [Groningen]
- Istituto di Radioastronomia [Bologna] (IRA) ; Istituto Nazionale di Astrofisica (INAF)
- Leiden Observatory [Leiden] ; Universiteit Leiden [Leiden]
- Lawrence Livermore National Laboratory (LLNL)
- University of Minnesota [MN, USA]
- University of Virginia [Charlottesville]
- University of Edinburgh
- Uniwersytet Jagielloński w Krakowie = Jagiellonian University (UJ)
- University of Southampton
- Max Planck Institute for Astrophysics ; Max-Planck-Gesellschaft
- Joseph Louis LAGRANGE (LAGRANGE) ; Université Nice Sophia Antipolis (1965 - 2019) (UNS) ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
- Observatoire de la Côte d'Azur ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)
- Thüringer Landessternwarte Tautenburg (TLS)
- Chalmers University of Technology [Gothenburg, Sweden]
- Oxford Astrophysics ; University of Oxford [Oxford]
- University of the Western Cape
- National Radio Astronomy Observatory [Socorro] (NRAO) ; National Radio Astronomy Observatory (NRAO)
- Johns Hopkins University (JHU)
- Institute of Space and Astronautical Science (ISAS) ; Japan Aerospace Exploration Agency [Sagamihara] (JAXA)
- The Open University [Milton Keynes] (OU)
- STFC Rutherford Appleton Laboratory (RAL) ; Science and Technology Facilities Council (STFC)
Description
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 ∼ 5′′ resolution, meeting the specifications of the LOFAR Tier-1 northern survey.
Abstract
International audience
Additional details
- URL
- https://hal.archives-ouvertes.fr/hal-03648687
- URN
- urn:oai:HAL:hal-03648687v1
- Origin repository
- UNICA