J/A+A/704/A65 LOFAR 58MHz Legacy Survey of 3CRR catalog (Boxelaarlaar+, 2025)
LOFAR 58 MHz Legacy Survey of the 3CRR catalogue.
Boxelaarlaar J.M., De Gasperin F., Hardcastle M.J., Croston J.H.,
Morabito L.K., van Weeren R.J., Edler H.
<Astron. Astrophys. 704, A65 (2025)>
=2025A&A...704A..65B 2025A&A...704A..65B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Redshifts ; Morphology
Keywords: techniques: interferometric - catalogs - galaxies: active -
galaxies: jets - radio continuum: galaxies
Abstract:
The Low Frequency Array (LOFAR) is uniquely able to perform deep,
high- resolution imaging at frequencies below 100MHz. Observations in
this regime, using the Low Band Antenna (LBA) system, are
significantly affected by instrumental and ionospheric distortions.
Recent developments in calibration techniques have enabled routine
production of high-fidelity images at these challenging frequencies.
The aim of this paper is to obtain images of the radio sources
included in the Third Cambridge catalog, second revised version (3CRR)
at an observing frequency of 58MHz, with an angular resolution of
approximately 15arcsec and sensitivity to both compact and diffuse
radio emission. This work also aims to produce accurate flux
measurements for all sources. This dataset is designed to serve as a
reference for low-frequency radio galaxy studies and future spectral
aging analyses. We present the data reduction and calibration
procedures developed for narrowband observations of bright sources
with the LOFAR LBA. These include tailored direction-independent
calibration strategies optimized for mitigating ionospheric phase
corruptions and instrumental effects at 58∼MHz. Imaging techniques
were refined to reliably recover both small- and large-scale radio
structures reliably. We deliver 58MHz radio images for the complete
3CRR sample, with flux density measurements exhibiting an average
uncertainty of 10%. These results offer new insights into the
energetics and evolution of radio galaxies at low frequencies. We also
provide high-resolution models of these sources which is useful for
calibrating future surveys. This legacy survey significantly expands
the available high-resolution data at low frequencies and is the first
fully imaged high-resolution sample at ultra low frequencies
(<100MHz). It lays the foundation for future studies of radio galaxy
physics, low-energy cosmic-ray populations, and the interplay between
radio jets and their environments.
Description:
3CRR Catalog containing flux density measurements at 58MHz and 144MHz
and spectral index between the two measurements from the LOFAR
Telescope. Table also contains th 58MHz image resolution and noise.
All 58MHz images are also available on https://www.lofar-surveys.org
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablec1.dat 85 173 3CRR catalogue observed at 58 MHz
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See also:
J/MNRAS/204/151 : Bright radio sources at 178 MHz (3CRR) (Laing+ 1983)
https://www.lofar-surveys.org : LOFAR Home Page
Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Object name
10- 18 F9.5 deg RAdeg Right Ascension (J2000)
20- 27 F8.5 deg DEdeg Declination (J2000)
29- 36 F8.6 --- z Redshift of the source
38- 44 F7.2 Jy S58 Flux density at 58MHz
46- 51 F6.2 Jy e_S58 Uncertainty on flux density at 58MHz
53- 56 F4.1 arcsec Bmaj Major axis of the restoring beam
58- 61 F4.1 arcsec Bmin Minor axis of the restoring beam
63- 70 F8.2 mJy/beam RMS RMS noise in the image
72- 77 F6.2 Jy S144 ?=-99 Flux density at 144MHz,
calculated from LoTSS HBA DR3 data
79- 85 F7.2 --- SpIndex ?=-99 Spectral index between 58MHz and 144MHz
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Acknowledgements:
Jort Boxelaar, j.boxelaar(at)ira.inaf.it
(End) Patricia Vannier [CDS] 27-Oct-2025