Characterising the Apertif primary beam response
Journal article, 2022
Context. Phased array feeds (PAFs) are multi-element receivers in the focal plane of a telescope that make it possible to simultaneously form multiple beams on the sky by combining the complex gains of the individual antenna elements. Recently, the Westerbork Synthesis Radio Telescope (WSRT) was upgraded with PAF receivers to carry out several observing programs, including two imaging surveys and a time-domain survey. The Apertif imaging surveys use a configuration of 40 partially overlapping compound beams (CBs) simultaneously formed on the sky and arranged in an approximately rectangular shape. Aims. This work is aimed at characterising the response of the 40 Apertif CBs to create frequency-resolved I, XX, and YY polarization empirical beam shapes. The measured CB maps can be used for the image deconvolution, primary beam correction, and mosaicking processes of Apertif imaging data. Methods. We used drift scan measurements to measure the response of each of the 40 Apertif CBs. We derived beam maps for all individual beams in I, XX, and YY polarisation in 10 or 18 frequency bins over the same bandwidth as the Apertif imaging surveys. We sampled the main lobe of the beams and the side lobes up to a radius of 0.6 degrees from the beam centres. In addition, we derived beam maps for each individual WSRT dish. Results. We present the frequency and time dependence of the beam shapes and sizes. We compared the compound beam shapes derived with the drift scan method to beam shapes derived with an independent method using a Gaussian Process Regression comparison between the Apertif continuum images and the NRAO VLA Sky Survey (NVSS) catalogue. We find a good agreement between the beam shapes derived with the two independent methods.
instrumentation
observational
instrumentation
methods
interferometers
telescopes
detectors
surveys
Author
H. Denes
Netherlands Institute for Radio Astronomy (ASTRON)
Kelley Michelle Hess
University of Groningen
Netherlands Institute for Radio Astronomy (ASTRON)
Spanish National Research Council (CSIC)
E. A. K. Adams
Netherlands Institute for Radio Astronomy (ASTRON)
University of Groningen
A. Kutkin
Netherlands Institute for Radio Astronomy (ASTRON)
Russian Academy of Sciences
R. Morganti
University of Groningen
Netherlands Institute for Radio Astronomy (ASTRON)
J. M. van der Hulst
University of Groningen
T. A. Oosterloo
Netherlands Institute for Radio Astronomy (ASTRON)
University of Groningen
V. A. Moss
The University of Sydney
Commonwealth Scientific and Industrial Research Organisation (CSIRO)
Netherlands Institute for Radio Astronomy (ASTRON)
B. Adebahr
Ruhr-Universität Bochum
W. J. G. de Blok
Netherlands Institute for Radio Astronomy (ASTRON)
University of Cape Town
University of Groningen
Marianna Ivashina
Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks
A. H. W. M. Coolen
Netherlands Institute for Radio Astronomy (ASTRON)
S. Damstra
Netherlands Institute for Radio Astronomy (ASTRON)
B. Hut
Netherlands Institute for Radio Astronomy (ASTRON)
G. M. Loose
Netherlands Institute for Radio Astronomy (ASTRON)
D. M. Lucero
Virginia Polytechnic Institute and State University
Y. Maan
Tata Institute of Fundamental Research
Netherlands Institute for Radio Astronomy (ASTRON)
A. Mika
Netherlands Institute for Radio Astronomy (ASTRON)
M. J. Norden
Netherlands Institute for Radio Astronomy (ASTRON)
L. C. Oostrum
University of Amsterdam
Netherlands Institute for Radio Astronomy (ASTRON)
Netherlands eScience Center
D. J. Pisano
West Virginia University
University of Cape Town
R. Smits
Netherlands Institute for Radio Astronomy (ASTRON)
W. A. van Cappellen
Netherlands Institute for Radio Astronomy (ASTRON)
R. van den Brink
Netherlands Institute for Radio Astronomy (ASTRON)
Tricas Industrial Design & Engineering
D. van der Schuur
Netherlands Institute for Radio Astronomy (ASTRON)
G. N. J. van Diepen
Netherlands Institute for Radio Astronomy (ASTRON)
J. van Leeuwen
Netherlands Institute for Radio Astronomy (ASTRON)
University of Amsterdam
D. Vohl
Netherlands Institute for Radio Astronomy (ASTRON)
University of Amsterdam
S. J. Wijnholds
Netherlands Institute for Radio Astronomy (ASTRON)
J. Ziemke
Netherlands Institute for Radio Astronomy (ASTRON)
University of Oslo
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 667 A40Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Radiology, Nuclear Medicine and Medical Imaging
DOI
10.1051/0004-6361/202244045