J/MNRAS/268/602 Compact radio cores in radio galaxies. (Jones+, 1994)
Compact radio cores in radio galaxies.
Jones P.A., McAdam W.B., Reynolds J.E.
<Mon. Not. R. Astron. Soc. 268, 602 (1994)>
=1994MNRAS.268..602J 1994MNRAS.268..602J
ADC_Keywords: Galaxies, radio ; Interferometry
Description:
This catalog contains compact core fluxes for a list of 175 southern
radio galaxies, measured with the Parkes-Tidbinbilla Interferometer
(PTI, Norris et al. 1988ApJS...67...85N 1988ApJS...67...85N) on a single 275 km baseline
at 2.3 GHz and 8.4 GHz. The sample consists of large angular size ( >
0.5 arcmin) steep spectrum sources from Jones & McAdam
(1992ApJS...80..137J 1992ApJS...80..137J) observed to determine the fraction of flux
contained in compact (VLBI-scale) cores.
Of the 172 sources observed at 2.3 GHz (100 milliarcsec fringe
spacing), 63 had cores detected and upper limits were determined for
the remaining 109. Of the 88 sources observed at 8.4 GHz (30
milliarcsec fringe spacing), 38 had cores detected and 50 have upper
limits. A comparison of the detections and upper limits at the two
frequencies shows that the cores have flat or inverted spectra. The
core fluxes quoted here may vary by around 20 % if there is structure
on the scale of the fringe spacing and the cores are probably
intrinsically variable.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
pti_core.dat 59 175 Compact Radio Cores in Radio Galaxies (Dec < -30d)
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Byte-by-byte Description of file: pti_core.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- name Name of source, from B1950 position (1)
12-18 F7.2 Jy S843t Total flux density at 843 MHz, in Jy (2)
22 A1 --- l_S2.3G [ <] Flag for 2.3 GHz core flux density (3)
23-26 I4 mJy S2.3G ? Core flux density or upper limit at 2.3 GHz (3)
30 A1 --- l_S8.4G [ <] flag for 8.4 GHz core flux density (3)
31-34 I4 mJy S8.4G ? Core flux density or upper limit at 8.4 GHz (3)
38 A1 --- l_Sp+Index [ <>] limit flag for spectral index (4)
39-43 F5.2 --- Sp+Index ? Core spectral index value, or upper/lower
limit (4)
45-46 I2 h RAh Right Ascension (B1950) (hour) (5)
47-48 I2 min RAm Right Ascension (B1950) (min)
49-52 F4.1 s RAs Right Ascension (B1950) (sec)
53 A1 --- DE- Declination sign (B1950) (5)
54-55 I2 deg DEd Declination (B1950) (deg)
56-57 I2 arcmin DEm Declination (B1950) (arcmin)
58-59 I2 arcsec DEs Declination (B1950) (arcsec)
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Note (1): This column gives the name of the source, comprised of the hours
and minutes of right ascension, the sign of the declination, the
degrees truncated to the nearest tenth of a degree, and a capital
letter (if the position code is ambiguous). The position used is the
radio centroid in B1950 coordinates from the 843 MHz MOST data (Jones
& McAdam 1992ApJS...80..137J 1992ApJS...80..137J) so the names may differ in some cases
from the source names in the Molonglo Reference Catalogue (MRC, Large
et al. 1981MNRAS.194..693L 1981MNRAS.194..693L, 1991) and PKSCAT90. Cats.VIII/16 and
VIII/15 respectively.
Note (2): This column gives the integrated flux density in Jy at 843 MHz
from observations with the Molonglo Observatory Synthesis Telescope
(MOST) from Jones & McAdam (1992ApJS...80..137J 1992ApJS...80..137J). The uncertainty is
estimated as ± 9 %.
Note (3): These columns give the core flux density, or upper limit, in mJy
at 2.3 and 8.4 GHz. These flux densities were measured from the fringe
amplitude on the single 275 km-baseline of the Parkes-Tidbinbilla
Interferometer (PTI, Norris et al. 1988ApJS...67...85N 1988ApJS...67...85N). If there is
source structure on the scale of the fringe spacing (100 milliarcsec
at 2.3 GHz and 30 milliarcsec at 8.4 GHz) then the flux densities
differ from the 'point source' flux. The cores are also expected to be
variable. The combined effect is to give any uncertainty estimated at
± 20 % in core flux. An example is Centaurus A = 1322-427 which has
structure on the Parkes-Tidbinbilla baseline and a variable core.
Note (4): These columns give the core spectral index (alpha, where core
flux density is proportional to frequency to the power alpha, i.e.,
Sν ∝ να), or upper/lower limits to core
spectral index, calculated from the core flux densities at 2.3 and 8.4
GHz. These spectral index values for individual sources should be
treated with caution: due to the effects of source structure on the
scale of the Parkes-Tidbinbilla baseline and source variability (since
the data at the two frequencies were taken months apart) the spectral
index has an uncertainty estimated as ± 0.2.
Note (5): These columns give the B1950 right ascension and declination of
the radio centroid position, in degrees and in radians, from the 843
MHz MOST data (Jones & McAdam 1992ApJS...80..137J 1992ApJS...80..137J). These positions
have an accuracy of 1.6" in right ascension and 2.2" cosec(dec) in
declination. Note that they are not the core positions.
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History:
"The catalogue was originally archived as R121 by H. Andernach
() and the ADS documentation prepared in
collaboration with Carolyn Stern Grant ()."
References:
Large, M.I., Cram, L.E., and Burgess, A.M., 1991, Observatory, 111, 72
(End) Patricio Ortiz [CDS] 07-Apr-1999