J/A+A/674/A189 Matching LOFAR sources across radio bands (Boehme+, 2023)
Matching LOFAR sources across radio bands.
Boehme L., Schwarz D.J., de Gasperin F., Roettgering H.J.A., Williams W.L.
<Astron. Astrophys. 674, A189 (2023)>
=2023A&A...674A.189B 2023A&A...674A.189B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Radio continuum
Keywords: radio continuum: general - galaxies: general -
methods: data analysis - catalogs
Abstract:
With the recent preliminary release of the LOFAR LBA Sky Survey
(LoLSS), the first wide-area, ultra-low frequency observations from
LOFAR were published. Our aim is to combine this dataset with other
surveys at higher frequencies to study the spectral properties of a
large sample of radio sources.
We present a new cross-matching algorithm taking into account the
sizes of the radio sources and apply it to the LoLSS-PR, LoTSS-DR1,
LoTSS-DR2 (all LOFAR), TGSS-ADR1 (GMRT), WENSS (WSRT) and NVSS (VLA)
catalogues. We then study the number of matched counterparts for LoLSS
radio sources and their spectral properties.
We find counterparts for 22 607 (89.5%) LoLSS sources. The remaining 2
640 sources (10.5%) are identified either as an artefact in the LoLSS
survey (3.6%) or flagged due to their closeness to bright sources
(6.9%). We find an average spectral index of α=-0.77±0.18
between LoLSS and NVSS. Between LoLSS and LoTSS-DR2 we find
α=-0.71±0.31. The average spectral index is flux density
independent above S54=181mJy. Comparison of the spectral slopes from
LoLSS-LoTSS-DR2 with LoTSS-DR2-NVSS indicates that the probed
population of radio sources exhibits evidence for a negative spectral
curvature.
Description:
We present a new cross-matching algorithm taking into account the
sizes of the radio sources and apply it to the LoLSS-PR, LoTSS-DR1,
LoTSS-DR2 (all LOFAR), TGSS-ADR1 (GMRT), WENSS (WSRT) and NVSS (VLA)
catalogues. We find counterparts for 22607 (89.5%) LoLSS sources. The
remaining 2640 sources (10.5%) are identified either as an artefact
in the LoLSS survey (3.6%) or flagged due to their closeness to bright
sources (6.9%). We find an average spectral index of
α=-0.77±0.18 between LoLSS and NVSS. Between LoLSS and
LoTSS-DR2 we find α=-0.71±0.31. The average spectral index is
flux density independent above S54=181mJy.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
c_match.dat 675 25247 Whole cross-matching catalogue (table 2)
hzrg.dat 24 46 High-redshift radio galaxy candidates
uss.dat 24 307 Ultra-steep spectrum sources (alpha less than -2)
steep_z.dat 29 9 High-redshift (z greater than 2) and steep
spectrum (alpha less than -1)
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See also:
VIII/62 : The Westerbork Northern Sky Survey (Leiden, 1998)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
J/A+A/655/A40 : LoLSS-Deep Bootes 54MHz catalog (Williams+, 2021)
J/A+A/598/A78 : The GMRT 150MHz all-sky radio survey (Intema+, 2017)
J/A+A/598/A104 : LOFAR Two-metre Sky Survey (Shimwell+, 2017)
J/A+A/622/A1 : LOFAR Two-metre Sky Survey (LoTSS) DR1 (Shimwell+, 2019)
J/A+A/659/A1 : LOFAR Two-metre Sky Survey (LoTSS) DR2 (Shimwell+, 2022)
Byte-by-byte Description of file: c_match.dat
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Bytes Format Units Label Explanations
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1- 20 A20 --- LoLSS LoLSS source identification,
LOLpJHHMMSS.s+DDMMSS (SourceIdL)
22- 39 F18.14 deg RAdeg LoLSS position (J2000) (RA)
41- 58 F18.15 deg DEdeg LoLSS position (J2000) (Dec)
60- 73 F14.7 mJy FluxLoLSS Sum of detection fluxes (Flux_LoLSS)
75- 86 F12.7 mJy e_FluxLoLSS Sum of detection flux errors
(eFluxLoLSS)
88-101 F14.7 mJy/beam PeakFluxLoLSS Max of detection peak fluxes
(PeakFluxLoLSS)
103-113 F11.7 mJy/beam e_PeakFluxLoLSS Max of detection peak flux errors
(ePeakFlux_LoLSS)
115-125 F11.7 mJy/beam rmsLoLSS Local rms noise (Rms_LoLSS)
127-140 F14.8 mJy FluxLoTSS1 ?=- Sum of detection fluxes
(Flux_LoTSS1)
142-153 F12.9 mJy e_FluxLoTSS1 ?=- Sum of detection flux errors
(eFluxLoTSS1)
155-167 F13.8 mJy/beam PeakFluxLoTSS1 ?=- Max of detection peak fluxes
(PeakFluxLoTSS1)
169-180 F12.9 mJy/beam e_PeakFluxLoTSS1 ?=- Max of detection peak flux errors
(ePeakFlux_LoTSS1)
182-193 F12.9 mJy/beam rmsLoTSS1 ?=- Local rms noise (Rms_LoTSS1)
195-208 F14.8 mJy FluxLoTSS2 ?=- Sum of detection fluxes
(Flux_LoTSS2)
210-221 F12.9 mJy e_FluxLoTSS2 ?=- Sum of detection flux errors
(eFluxLoTSS2)
223-235 F13.8 mJy/beam PeakFluxLoTSS2 ?=- Max of detection peak fluxes
(PeakFluxLoTSS2)
237-248 F12.10 mJy/beam e_PeakFluxLoTSS2 ?=- Max of detection peak flux errors
(ePeakFlux_LoTSS2)
250-260 F11.9 mJy/beam rmsLoTSS2 ?=- Local rms noise (Rms_LoTSS2)
262-273 F12.6 mJy FluxTGSS ?=- Sum of detection fluxes
(Flux_TGSS)
275-286 F12.7 mJy e_FluxTGSS ?=- Sum of detection flux errors
(eFluxTGSS)
288-299 F12.6 mJy/beam PeakFluxTGSS ?=- Max of detection peak fluxes
(PeakFluxTGSS)
301-312 F12.7 mJy/beam e_PeakFluxTGSS ?=- Max of detection peak flux errors
(ePeakFlux_TGSS)
314-323 F10.7 mJy/beam rmsTGSS ?=- Local rms noise (Rms_TGSS)
325-331 F7.1 mJy FluxWENSS ?=- Sum of detection fluxes
(Flux_WENSS)
333-334 A2 mJy e_FluxWENSS ?=- Sum of detection flux errors
(eFluxWENSS)
336-341 F6.1 mJy/beam PeakFluxWENSS ?=- Max of detection peak fluxes
(PeakFluxWENSS)
343-344 A2 mJy/beam e_PeakFluxWENSS ?=- Max of detection peak flux errors
(ePeakFlux_WENSS)
346-355 F10.7 mJy/beam rmsWENSS ?=- Local rms noise (Rms_WENSS)
357-362 F6.1 mJy FluxNVSS ?=- Sum of detection fluxes
(Flux_NVSS)
364-367 F4.1 mJy e_FluxNVSS ?=- Sum of detection flux errors
(eFluxNVSS)
369-380 F12.7 mJy/beam PeakFluxNVSS ?=- Max of detection peak fluxes
(PeakFluxNVSS)
382-383 A2 mJy/beam e_PeakFluxNVSS ?=- Max of detection peak flux errors
(ePeakFlux_NVSS)
385-397 F13.11 mJy/beam rmsNVSS ?=- Local rms noise (Rms_NVSS)
399-412 F14.11 --- SpILT1 ?=- Spectral index between LoLSS and
LoTSS-DR1 (Spidx_LT1)
414-426 E13.6 --- SpILT2 ?=- Spectral index between LoLSS and
LoTSS-DR2 (Spidx_LT2)
428-441 F14.11 --- SpILG ?=- Spectral index between LoLSS and
TGSS (Spidx_LG)
443-456 E14.6 --- SpILW ?=- Spectral index between LoLSS and
WENSS (Spidx_LW)
458-470 F13.10 --- SpILN ?=- Spectral index between LoLSS and
NVSS (Spidx_LN)
472 A1 --- Scode [SMA] (S)ingle, (M)ultiple,
(A)rtefact/Close to bright (Scode)
474 I1 --- NumMatchT1 [0/6] Number of LoTSS-DR1 counterparts
(NummatchT1)
476-512 A37 --- SourceIdT1 Array of source IDs with NumMatchT1
entries (SourceidT1)
514 I1 --- NumMatchT2 [0/9] Number of LoTSS-DR2 counterparts
(NummatchT2)
516-579 A64 --- SourceIdT2 Array of source IDs with NumMatchT2
entries (SourceidT2)
581 I1 --- NumMatchG [0/3] Number of TGSS counterparts
(NummatchG)
583-604 A22 --- SourceIdG Array of source IDs with NumMatchG
entries (SourceidG)
606 I1 --- NumMatchW [0/5] Number of WENSS counterparts
(NummatchW)
608-643 A36 --- SourceIdW Array of source IDs with NumMatchW
entries (SourceidW)
645 I1 --- NumMatchN [0/4] Number of NVSS counterparts
(NummatchN)
647-675 A29 --- SourceIdN Array of source IDs with NumMatchN
entries (SourceidN)
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Byte-by-byte Description of file: hzrg.dat uss.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right ascension (J2000)
10- 18 F9.5 deg DEdeg Declination (J2000)
20- 24 F5.2 --- SpIndex Spectral Index between LoLSS and LoTSS-DR2
-------------------------------------------------------------------------------
Byte-by-byte Description of file: steep_z.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right ascension (J2000)
10- 18 F9.5 deg DEdeg Declination (J2000)
20- 24 F5.2 --- SpIndex Spectral Index between LoLSS and LoTSS-DR2
26- 29 F4.2 --- z Redshift from LoTSS-DR1 value-added catalogue
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Acknowledgements:
Lukas Boehme, Lboehme(at)physik.uni-bielefeld.de
(End) Patricia Vannier [CDS] 01-Mar-2023