The Faraday Rotation Measure Grid of the LOFAR Two-metre Sky Survey: Data Release 2
Artikel i vetenskaplig tidskrift, 2023
A Faraday rotation measure (RM) catalogue, or RM Grid, is a valuable resource for the study of cosmic magnetism. Using the second data release (DR2) from the LOFAR Two-metre Sky Survey (LoTSS), we have produced a catalogue of 2461 extragalactic high-precision RM values across 5720 deg(2) of sky (corresponding to a polarized source areal number density of similar to 0.43 deg(-2)). The linear polarization and RM properties were derived using RM synthesis from the Stokes Q and U channel images at an angular resolution of 20 arcsec across a frequency range of 120 to 168 MHz with a channel bandwidth of 97.6 kHz. The fraction of total intensity sources (>1 mJy beam(-1)) found to be polarized was similar to 0.2 percent. The median detection threshold was 0.6 mJy beam(-1) (8 sigma(QU)), with a median RM uncertainty of 0.06 rad m(-2) (although a systematic uncertainty of up to 0.3 radm(-2) is possible, after the ionosphere RM correction). The median degree of polarization of the detected sources is 1.8 percent, with a range of 0.05 percent to 31 percent. Comparisons with cm-wavelength RMs indicate minimal amounts of Faraday complexity in the LoTSS detections, making them ideal sources for RM Grid studies. Host galaxy identifications were obtained for 88 percent of the sources, along with redshifts for 79 percent (both photometric and spectroscopic), with the median redshift being 0.6. The focus of the current catalogue was on reliability rather than completeness, and we expect future versions of the LoTSS RM Grid to have a higher areal number density. In addition, 25 pulsars were identified, mainly through their high degrees of linear polarization.
catalogues
techniques: polarimetric
magnetic fields
polarization
galaxies: active
radio continuum: galaxies
Författare
S. P. O'Sullivan
Dublin City University
T. W. Shimwell
Universiteit Leiden
Netherlands Institute for Radio Astronomy (ASTRON)
M. J. Hardcastle
University of Hertfordshire
C. Tasse
Rhodes University
Université de recherche Paris Sciences et Lettres
G. Heald
CSIRO Astronomy and Space Science
E. Carretti
Istituto nazionale di astrofisica (INAF)
M. Bruggen
Universität Hamburg
V. Vacca
INAF Osservatorio Astronomico di Cagliari
C. Sobey
CSIRO Astronomy and Space Science
C. L. Van Eck
University of Toronto
Cathy Horellou
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
R. Beck
Max-Planck-Gesellschaft
M. Bilicki
Polish Academy of Sciences
Stephen Bourke
Chalmers, Rymd-, geo- och miljövetenskap, Onsala rymdobservatorium
A. Botteon
Universiteit Leiden
J. H. Croston
Open University
A. Drabent
Thüringer Landessternwarte Tautenburg
K. Duncan
Royal Observatory
V Heesen
Universität Hamburg
S. Ideguchi
National Astronomical Observatory of Japan
M. Kirwan
Dublin City University
L. Lawlor
Dublin City University
B. Mingo
Open University
B. Nikiel-Wroczynski
Uniwersytet Jagiellonski w Krakowie
J. Piotrowska
Uniwersytet Jagiellonski w Krakowie
A. M. M. Scaife
Alan Turing Institute
University of Manchester
R. J. van Weeren
Universiteit Leiden
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 519 4 5723-5742Ämneskategorier
Acceleratorfysik och instrumentering
Astronomi, astrofysik och kosmologi
Atom- och molekylfysik och optik
DOI
10.1093/mnras/stac3820