J/ApJS/276/38 The Radio Fundamental Catalog - RFC (Petrov+, 2025)
The Radio Fundamental Catalog. I. Astrometry.
Petrov L.Y., Kovalev Y.Y.
<Astrophys. J. Suppl. Ser. 276, 38 (2025)>
=2025ApJS..276...38P 2025ApJS..276...38P (SIMBAD/NED BibCode)
ADC_Keywords: VLBI ; Radio sources ; Active gal. nuclei ; Proper motions ;
Fundamental catalog ; Positional data
Keywords: very long baseline interferometry - astrometry -
active galactic nuclei
Abstract:
We present an all-sky catalog of absolute positions and estimates of
correlated flux density of 21942 compact radio sources determined
from processing interferometric visibility data of virtually all very
long baseline interferometry (VLBI) observing sessions at 2-23GHz
from 72 programs suitable for absolute astrometry collected for 30yr.
We used a novel technique of generation of a data set of fused
observables that allowed us to incorporate all available data in our
analysis. The catalog is the most complete and most precise to date.
It forms the foundation and reference for positional astronomy, space
geodesy, space navigation, and population analysis of active galactic
nuclei (AGNs), and provides calibrators for phase referencing for
differential astrometry and VLBI astrophysical observations. Its
accuracy was evaluated through a detailed accounting of systematic
errors, rigorous decimation tests, comparison of different data sets,
and comparison with other catalogs. The catalog preferentially samples
AGNs with strong contemporary parsec-scale synchrotron emission. Its
milliarcsecond-level positional accuracy allows association of these
AGNs with detections in a wide range of the electromagnetic spectrum
from low-frequency radio to gamma rays and high-energy neutrinos. We
describe the innovative data processing and calibration technique in
full detail, report the in depth analysis of random and systematic
positional errors, and provide a list of associations with large
surveys at different wavelengths.
Description:
The Radio Fundamental Catalog presents an all-sky catalog of absolute
positions and estimates of correlated flux density of 21942 compact
radio sources determined from processing interferometric visibility
data of virtually all very long baseline interferometry (VLBI)
observing sessions at 2-23GHz from 72 programs suitable for absolute
astrometry collected for 30 years. The catalogue supersedes all prior
VLBI astrometry catalogues published to date. It forms the foundation
and reference for positional astronomy, space geodesy, space
navigation, and population analysis of active galactic nuclei (AGNs),
and provides calibrators for phase referencing for differential
astrometry and VLBI astrophysical observations. The catalog
preferentially samples AGNs with strong contemporary parsec-scale
synchrotron emission. Its milliarcsecond-level positional accuracy
allows association of these AGNs with detections in a wide range of
the electromagnetic spectrum from low-frequency radio to gamma-rays
and high-energy neutrinos. We describe the innovative data processing
and calibration technique in full detail, report the in depth analysis
of random and systematic positional errors, and provide a list of
associations with large surveys at different wavelengths.
This catalogue has designator rfc_2024c and corresponds to
the version presented in 2025ApJS..276...38P 2025ApJS..276...38P
The catalogue is updated on a quarterly basis.
See https://doi.org/10.25966/dhrk-zh08 : Quarterly update of the RFC
The flux density estimates for the catalogue are taken
from the Astrogeo VLBI FITS image database that is available
at https://doi.org/10.25966/kyy8-yp57 : VLBI image database
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table7.dat 57 23 Proper motion of Galactic objects
table9.dat 222 21942 Positions and flux densities derived from
fused observables
table10.dat 311 21942 Offsets of dual-band and single-band position
estimates
table11.dat 629 21942 Cross-match of the RFC with 14 surveys
table12.dat 29 20000 Non-detected sources from observations at 4-8GHz
table13.dat 17 181 Additive error floor model
table14.dat 37 137 Non-canonical RFC designators
table15.dat 48 427 Non-canonical common names
table16.dat 34 104 Pairs of RFC sources within 1 arcminute
table20.dat 128 73 List of VLBI absolute astronomy observing
campaigns
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name RFC source designator
(RFC JHHMM+DDMM or RFC JHHMM+DDMA)
16- 21 A6 --- Type Object type: star, pulsar or supernova (SN)
23- 29 F7.2 mas/yr pmRA ? Proper motion in right ascension
31- 37 F7.2 mas/yr pmDE ? Proper motion in declination
39- 43 F5.2 mas/yr e_pmRA ? Uncertainty of the proper motion
in right ascension (1)
45- 49 F5.2 mas/yr e_pmDE ? Uncertainty of the proper motion
in declination
51- 57 F7.4 --- Corrpm ? Correlation between proper motions
in RA and DE
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Note (1): Without cos(delta) factor applied.
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Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name RFC source designator
(RFC JHHMM+DDMM or RFC JHHMM+DDMA)
17- 24 A8 --- CName Common name
27- 28 I2 h RAh Hours of Right Ascension (J2000)
30- 31 I2 min RAm Minutes of Right Ascension (J2000)
33- 41 F9.6 s RAs Seconds of Right Ascension (J2000)
43 A1 --- DE- Sign of the Declination (J2000)
44- 45 I2 deg DEd Degrees of Declination (J2000)
47- 48 I2 arcmin DEm Arcminutes of Declination (J2000)
50- 57 F8.5 arcsec DEs Arcseconds of Declination (J2000)
60- 65 F6.2 mas e_RAs Error in right ascension without cos(delta)
factor
67- 72 F6.2 mas e_DEs Error in declination
76- 81 F6.3 --- Corr Correlation between right ascension and
declination
83- 89 I7 --- Nobs Number of observations used in the fused
solution
91- 96 I6 --- Nsca Number of scans used in the fused solution
98-102 I5 --- Nses Number of observing sessions used in the fused
solution
105-110 F6.3 Jy FsS ?=-9.99 Median flux density at S-band
(2.2-2.4GHz) at baseline projection lengths
shorter than 1000km (1)
112-117 F6.3 Jy FmS ?=-9.99 Median flux density at S-band
(2.2-2.4GHz) at baseline projection lengths
in a range 1000 to 5000km (1)
119-124 F6.3 Jy FlS ?=-9.99 Median flux density at S-band
(2.2-2.4GHz) at baseline projection lengths
shorter than 1000km (1)
126 A1 --- l_FsC Limit flag on FsC
127-132 F6.3 Jy FsC ?=-9.99 Median flux density at C-band
(4.1-5.0GHz) at baseline projection lengths
shorter than 1000km (1)
134-139 F6.3 Jy FmC ?=-9.99 Median flux density at C-band
(4.1-5.0GHz) at baseline projection lengths
in a range 1000 to 5000km (1)
140 A1 --- l_FlC Limit flag on FlC
141-146 F6.3 Jy FlC ?=-9.99 Median flux density at C-band
(4.1-5.0GHz) at baseline projection lengths
shorter than 1000km (1)
148 A1 --- l_FsX Limit flag on FsX
149-154 F6.3 Jy FsX ?=-9.99 Median flux density at X-band
(7.3-8.8GHz) at baseline projection lengths
shorter than 1000km (1)
156-161 F6.3 Jy FmX ?=-9.99 Median flux density at X-band
(7.3-8.8GHz) at baseline projection lengths
in a range 1000 to 5000km (1)
163-168 F6.3 Jy FlX ?=-9.99 Median flux density at X-band
(7.3-8.8GHz) at baseline projection lengths
shorter than 1000km (1)
170 A1 --- l_FsU Limit flag on FsU
171-176 F6.3 Jy FsU ?=-9.99 Median flux density at U-band
(15.2-15.5GHz) at baseline projection lengths
shorter than 1000km (1)
178-183 F6.3 Jy FmU ?=-9.99 Median flux density at U-band
(15.2-15.5GHz) at baseline projection lengths
in a range 1000 to 5000km (1)
185-190 F6.3 Jy FlU ?=-9.99 Median flux density at U-band
(15.2-15.5GHz) at baseline projection lengths
shorter than 1000km (1)
193-198 F6.3 Jy FsK ?=-9.99 Median flux density at K-band
(22.0-24.3GHz) at baseline projection lengths
shorter than 1000km (1)
200-205 F6.3 Jy FmK ?=-9.99 Median flux density at K-band
(22.0-24.3GHz) at baseline projection lengths
in a range 1000 to 5000km (1)
207-212 F6.3 Jy FlK ?=-9.99 Median flux density at K-band
(22.0-24.3GHz) at baseline projection lengths
shorter than 1000km (1)
215-222 F8.3 yr MeaEpo Weighted mean epoch of observations
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Note (1): -9.99 indicates a Null value: no estimate is available.
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Byte-by-byte Description of file: table10.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name RFC source designator
(RFC JHHMM+DDMM or RFC JHHMM+DDMA)
16- 21 F6.2 mas e_RAs Error in right ascension (1)
23- 28 F6.2 mas e_DEs Error in declination
30- 35 I6 --- Nobs Number of observations used in the fused solution
37- 42 I6 --- Nsca Number of scans used in the fused solution
44- 48 I5 --- Nses Number of observing sessions used in the fused
50- 56 F7.2 mas oRAD ?=-99.99 Offset of the dual-band position along
the right ascension axis (1) (2) (3)
58- 64 F7.2 mas oDED ?=-99.99 Offset of the dual-band position along
the declination axis (2) (3)
66- 71 F6.2 mas e_oRAD ?=-99.99 Uncertainty of the dual-band position
a long the right ascension axis (1) (2)
73- 78 F6.2 mas e_oDED ?=-99.99 Uncertainty of the dual-band position
a long the declination axis (2)
80- 86 F7.3 --- CorrD ?=-99.99 Correlation between right ascension and
declination of the dual-band source
position (2)
88- 92 I5 --- NobsD Number of observations used in the dual-band
solution
94- 97 I4 --- NscaD Number of scans used in the dual-band
solution
99-101 I3 --- NsesD Number of observing sessions used in the
dual-band solution
103-109 F7.2 mas oRAS ?=-99.99 Offset of the S-band position along
the right ascension axis (1) (2) (3)
111-117 F7.2 mas oDES ?=-99.99 Offset of the S-band position along
the declination axis (2) (3)
119-124 F6.2 mas e_oRAS ?=-99.99 Uncertainty of the S-band position
along the right ascension axis (1) (2)
126-131 F6.2 mas e_oDES ?=-99.99 Uncertainty of the S-band position
along the declination axis (2)
133-139 F7.3 --- CorrS ?=-99.99 Correlation between right ascension
and declination of the S-band source
position (2)
141-145 I5 --- NobsS Number of observations used in the S-band
solution
147-150 I4 --- NscaS Number of scans used in the S-band solution
152-154 I3 --- NsesS Number of observing sessions used in the
S-band solution
156-162 F7.2 mas oRAC ?=-99.99 Offset of the C-band position along
the right ascension axis (1) (2) (3)
164-170 F7.2 mas oDEC ?=-99.99 Offset of the C-band position along
the declination axis (2) (3)
172-177 F6.2 mas e_oRAC ?=-99.99 Uncertainty of the C-band position
along the right ascension axis (1) (2)
179-184 F6.2 mas e_oDEC ?=-99.99 Uncertainty of the C-band position
along the declination axis (2)
186-192 F7.3 --- CorrC ?=-99.99 Correlation between right ascension
and declination of the C-band source
position (2)
194-197 I4 --- NobsC Number of observations used in
the C-band solution
199-201 I3 --- NscaC Number of scans used in the C-band solution
203-206 I4 --- NsesC Number of observing sessions used in the
C-band solution
208-214 F7.2 mas oRAX ?=-99.99 Offset of the X-band position along
the right ascension axis (1) (2) (3)
216-222 F7.2 mas oDEX ?=-99.99 Offset of the X-band position along
the declination axis (2) (3)
224-229 F6.2 mas e_oRAX ?=-99.99 Uncertainty of the X-band position
along the right ascension axis (1) (2)
231-236 F6.2 mas e_oDEX ?=-99.99 Uncertainty of the X-band position
along the declination axis (2)
238-244 F7.3 --- CorrX ?=-99.99 Correlation between right ascension and
declination of the X-band source position (2)
246-250 I5 --- NobsX Number of observations used in
the X-band solution
252-255 I4 --- NscaX Number of scans used in the X-band solution
257-259 I3 --- NsesX Number of observing sessions used in the
X-band solution
261-267 F7.2 mas oRAK ?=-99.99 Offset of the K-band position along
the right ascension axis (1) (2) (3)
269-275 F7.2 mas oDEK ?=-99.99 Offset of the K-band position along
the declination axis (2) (3)
277-282 F6.2 mas e_oRAK ?=-99.99 Uncertainty of the K-band position
along the right ascension axis (1) (2)
284-289 F6.2 mas e_oDEK ?=-99.99 Uncertainty of the K-band position
along the declination axis (2)
291-297 F7.3 --- CorrK ?=-99.99 Correlation between right ascension and
declination of the K-band source position (2)
299-303 I5 --- NobsK Number of observations used in
the K-band solution
305-307 I3 --- NscaK Number of scans used in the K-band solution
309-311 I3 --- NsesK Number of observing sessions used in the
K-band solution
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Note (1): Without cos(delta) factor applied.
Note (2): Null values -99.99 is used to mark the quantities that are missing.
Note (3): Offsets are provide with respect to the positions derived from the
fused group delay observables. These positions are listed in the main table
(Table 9).
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Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Source designator
(RFC JHHMM+DDMM or RFC JHHMM+DDMA)
17- 34 A18 --- NVSS Name of the association in the NVSS catalog
36- 42 F7.3 arcsec NVSSDist ? Angular distance to the association
in the NVSS catalog (1)
44- 50 F7.5 --- NVSSpfa ? The probability of false association with
a counterpart from the NVSS catalog
53- 83 A31 --- VLASS Name of the association in the VLASS catalog
85- 91 F7.3 arcsec VLASSDist ? Angular distance to the association
in the VLASS catalog (1)
93- 99 F7.5 --- VLASSpfa ? The probability of false association
with a counterpart from the VLASS catalog
102-121 A20 --- SUMSS Name of the association in the SUMSS catalog
123-129 F7.3 arcsec SUMSSDist ? Angular distance to the association
in the SUMSS catalog (1)
131-137 F7.5 --- SUMSSpfa ? The probability of false association
with a counterpart from the SUMSS catalog
140-160 A21 --- TGSS Name of the association in the TGSS catalog
162-168 F7.3 arcsec TGSSDist ? Angular distance to the association
in the TGSS catalog (1)
170-176 F7.5 --- TGSSpfa ? The probability of false association
with a counterpart from the TGSS catalog
179-198 A20 --- AT20G Name of the association in the AT20G catalog
200-206 F7.3 arcsec AT20GDist ? Angular distance to the association
in the AT20G catalog (1)
208-214 F7.5 --- AT20Gpfa ? The probability of false association with a
counterpart from the AT20G catalog
217-244 A28 --- Gaia Name of the association in the Gaia EDR3
catalog
246-252 F7.5 arcsec GaiaDist ? Angular distance to the association
in the Gaia catalog (1)
254-260 F7.5 --- Gaiapfa ? The probability of false association with a
counterpart from the Gaia catalog
263-284 A22 --- PS1 Name of the association in the PS1
catalog, PanSTARRS data release 1
286-292 F7.5 arcsec PS1Dist ? Angular distance to the association
in the PS1 catalog (1)
294-300 F7.5 --- PS1pfa ? The probability of false association
with a counterpart from the PS1 catalog
303-326 A24 --- WISE Name of the association in the WISE
catalog, ALL-WISE data release
328-334 F7.5 arcsec WISEDist ? Angular distance to the association
in the WISE catalog (1)
336-342 F7.5 --- WISEpfa ? The probability of false association
with a counterpart from the WISE catalog
345-369 A25 --- 2MASS Name of the association in the 2MASS catalog
371-377 F7.5 arcsec 2MASSDist ? Angular distance to the association
in the 2MASS catalog (1)
379-385 F7.5 --- 2MASSpfa ? The probability of false association
with a counterpart from the 2MASS catalog
388-412 A25 --- GALEX Name of the association in the GALEX catalog
414-420 F7.3 arcsec GALEXDist ? Angular distance to the association
in the GALEX catalog (1)
422-428 F7.5 --- GALEXpfa ? The probability of false association with a
counterpart from the GALEX catalog
431-451 A21 --- 2RXS Name of the association in the 2RXS catalog
453-459 F7.3 arcsec 2RXSDist ? Angular distance to the association
in the 2RXS catalog (1)
461-467 F7.5 --- 2RXSpfa ? The probability of false association
with a counterpart from the 2RXS catalog
470-492 A23 --- XMMSL Name of the association in the XMMSL catalog
494-500 F7.3 arcsec XMMSLDist ? Angular distance to the association
in the XMMSL catalog (1)
502-508 F7.5 --- XMMSLpfa ? The probability of false association
with a counterpart from the XMMSL catalog
511-533 A23 --- 1eRASS Name of the association in the 1eRASS
catalog
535-541 F7.3 arcsec 1eRASSDist ? Angular distance to the association
in the 1eRASS catalog (1)
543-549 F7.5 --- 1eRASSpfa ? The probability of false association
with a counterpart from the 1eRASS catalog
552-568 A17 --- FERMI Name of the association in the FERMI catalog
570-576 F7.1 arcsec FERMIDist ? Angular distance to the association
in the FERMI catalog (1)
578-584 F7.5 --- FERMIpfa ? The probability of false association
with a counterpart from the FERMI catalog
587-592 F6.1 deg PA [-180/180]? Jet position angle
595-601 F7.4 --- z ? Redshift
603-621 A19 --- r_z ADS reference to the redshift
624-629 A6 --- Type Source type according to NED
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Note (1): Null value (i.e. blank column) means no association with the
probability of false association < 0.01 has been established.
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Byte-by-byte Description of file: table12.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Hours of Right Ascension (J2000)
4- 5 I2 min RAm Minutes of Right Ascension (J2000)
7- 11 F5.2 s RAs Seconds of Right Ascension (J2000)
13 A1 --- DE- Sign of the Declination (J2000)
14- 15 I2 deg DEd Degrees of Declination (J2000)
17- 18 I2 arcmin DEm Arcminutes of Declination (J2000)
20- 23 F4.1 arcsec DEs Arcseconds of Declination (J2000)
25- 29 F5.1 mJy Flux Upper limit on the expected correlated flux
density
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Byte-by-byte Description of file: table13.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 F5.1 deg DEdeg Declination
7- 11 F5.3 mas RAfloor Right ascension error floor
13- 17 F5.3 mas DEfloor Declination error floor
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Byte-by-byte Description of file: table14.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Non-canonical RFC designator
(RFC JHHMM+DDMM or RFC JHHMM+DDMA)
16- 25 A10 --- RFC RFC designator to the closest source with
a canonical designator
27- 31 A5 --- Reason Reason of assigning a non-canonical name
33- 37 F5.1 arcsec Sep ? Distance to the corresponding source
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Byte-by-byte Description of file: table15.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name RFC designator of a source with non-canonical
common name
(RFC JHHMM+DDMM or RFCJ HHMM+DDMA)
16- 23 A8 --- Non-Common Non-canonical common name
25- 32 A8 --- Common Common canonical name of the closest source
34- 41 A8 --- Reason Reason of assigning a non-canonical name
43- 48 F6.1 arcsec Sep ? Distance to the corresponding source
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Byte-by-byte Description of file: table16.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name1 RFC designator of the first source in the pair
(RFC JHHMM+DDMM or RFCJ HHMM+DDMA)
16- 29 A14 --- Name2 RFC designator of the second source in the pair
(RFC JHHMM+DDMM or RFCJ HHMM+DDMA)
31- 34 F4.1 arcsec Sep Arc distance between the sources in the pair
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Byte-by-byte Description of file: table20.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- Survey Survey (1)
3- 13 A11 --- Campaign Campaign (2)
15- 18 A4 --- Network Network
20- 26 A7 --- ID Observation ID
28- 66 A39 --- Ref References (3)
68- 71 F4.1 GHz Freq-lo ? Frequency, low
73- 76 F4.1 GHz Freq-hi ? Frequency, high
78- 82 I5 h Dur Duration, hours
84- 87 I4 --- Num Number of session
89- 98 A10 --- Start Start Date, YYYY.MM.DD
100-109 A10 --- End End Date, YYYY.MM.DD
111-115 I5 --- Nobs Number of sources, observed
117-121 I5 --- Ndet Number of sources, detected
123-128 I6 --- Nunq Number of sources, unique (4)
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Note (1): Survey number as follows:
1 = Pathfinder;
2 = Astrometric follow-ups;
3 = High frequency extensions;
4 = Total number of all survey observations.
Note (2): Null value (i.e. blank column) means campaign name is unknown
Note (3): Either the ADS bibcode the reference or the PI of the observation
Note (4): A source that was detected in that campaign is considered unique
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Acknowledgements:
Leonid Petrov, Leonid.Petrov(at)nasa.gov
(End) Leonid Petrov [NASA GSFC], Patricia Vannier [CDS] 04-Aug-2025