J/A+A/691/A347 LOFAR ELAIS-N1 field at 144MHz catalog (Ye+, 2024)
1-arcsecond imaging of ELAIS-N1 field at 144MHz using the LoTSS survey
with international LOFAR telescope.
Ye H., Sweijen F., van Weeren R.J., Williams W., de Jong J., Morabito L.K.,
Rottgering H., Shimwell T.W., Best P.N., Bondi M., Brueggen M.,
de Gasperin F., Tasse C.
<Astron. Astrophys. 691, A347 (2024)>
=2024A&A...691A.347Y 2024A&A...691A.347Y (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Radio continuum ; Interferometry
Keywords: techniques: image processing - catalogs - surveys -
radio continuum: general
Abstract:
We present the first wide area (2.5x2.5deg2) LOFAR High Band
Antenna image at a resolution of 1.2arcsecx2arcsec with a median
noise of approximately 80 microJy per beam. It was made from an 8-hour
International LOFAR Telescope (ILT) observation of the ELAIS-N1 field
at frequencies ranging from 120 to 168MHz with the most up-to-date
ILT imaging methods. This intermediate resolution falls between the
highest possible resolution (0.3arcsec) achievable by using all
International LOFAR Telescope (ILT) baselines and the standard
6-arcsecond resolution in the LoTSS (LOFAR Two-meter Sky Survey) image
products utilizing the LOFAR Dutch baselines only. This is the first
demonstration of the feasibility of imaging using the ILT at a
resolution of around 1 arcsec, which provides unique information on
source morphology at scales that fall below the surface brightness
limits at higher resolutions. The total calibration and imaging
computational time is approximately 52000 core hours, nearly 5 times
more than required to produce a 6 arcsec resolution image. We also
present a radio source catalogue containing 2263 sources detected over
the 2.5x2.5deg2 image of the ELAIS-N1 field, with a peak intensity
threshold of 5.5 sigma. The catalogue has been cross-matched with the
LoTSS deep ELAIS-N1 field radio catalogue, and its flux density and
positional accuracy have been investigated and corrected accordingly.
We find that approximately 80% of sources which we expect to be
detectable based on their peak brightness in the LoTSS 6 arcsec
resolution image are detected in this image, which is approximately a
factor of two higher than for 0.3 arcsec resolution imaging in the
Lockman Hole, implying there is a wealth of information on these
intermediate scales.
Description:
This radio source catalogue contains 2263 sources detected over a
2.5x2.5deg2 image of the ELAIS-N1 field, with a peak intensity
threshold of 5.5 sigma. The image has a resolution of
1.2arcsecx2arcsec with a median noise of approximately 80 microJy per
beam. It was made from an 8-hour International LOFAR Telescope (ILT)
observation of the ELAIS-N1 field at frequencies ranging from 120 to
168 MHz. The catalogue has been cross-matched with the LoTSS deep
ELAIS-N1 field radio catalogue, and its flux density and positional
accuracy have been investigated and corrected accordingly.
This PyBDSF generated radio catalogue has 2263 sources. This
catalogue is similar to the Elais-N1 deep field catalogue presented by
Sabater, J., Best, P. N., Tasse, C., et al. 2021A&A...648A...2S 2021A&A...648A...2S, Cat.
J/A+A/648/A2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 345 2263 ILT 1arcsec Elais-N1 final catalog
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See also:
J/A+A/648/A2 : LOFAR Two-metre Sky Survey Deep Fields DR1 (Sabater+, 2021)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Name Source name (Source_name)
24- 41 F18.14 deg RAdeg Right ascension (J2000) (RA)
43- 64 E22.16 deg e_RAdeg Right ascension uncertainty (E_RA)
66- 83 F18.15 deg DEdeg Declination (DEC)
85-106 E22.16 deg e_DEdeg Declination uncertainty (E_DEC)
109-132 E24.16 mJy Ftot Integrated source flux density at 144MHz
(Total_flux)
134-157 E24.16 mJy e_Ftot Integrated source flux density at 144MHz
uncertainty (ETotalflux)
159-182 E24.16 mJy/beam Fpeak Peak intensity at 144MHz (Peak_flux)
183-204 E22.16 mJy/beam e_Fpeak Peak intensity uncertainty at 144MHz
(EPeakflux)
207-230 E24.16 arcsec Maj Deconvolved major-axis (Maj) (1)
232-255 E24.16 arcsec e_Maj Deconvolved major-axis uncertainty (E_Maj)
257-280 E24.16 arcsec Min Deconvolved minor-axis (Min) (1)
281-302 E22.16 arcsec e_Min Deconvolved minor-axis uncertainty (E_Min)
304-323 F20.16 deg PA Position angle (PA) (1)
325-345 F21.17 deg e_PA Position angle uncertainty (E_PA)
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Note (1): Fitted shape parameters as determined by PyBDSF.
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Acknowledgements:
Haoyang Ye, hy297(at)cam.ac.uk
(End) Patricia Vannier [CDS] 28-Sep-2024