VIII/16 Molonglo Reference Catalogue of Radio Sources (Large+ 1991)
Molonglo Reference Catalogue of Radio Sources
Large M.I., Cram L.E., and Burgess A.M.
<The Observatory, 111, 72 (1991)>
=1991Obs...111...72L 1991Obs...111...72L
ADC_Keywords: Radio sources
Description:
"408-MHz survey observations made with the Molonglo Radio Telescope
have been used to prepare a catalogue of 12 141 discrete sources of
listed flux density ≥ 0.7 Jy. The survey covers 7.85 sr of the sky
defined by +18.5 (deg) ≥ dec(1950) ≥ -85.0 (deg), mod(b) ≥ 3 (deg).
A few sources beyond the declination limits are also included. The
catalogue comprises celestial coordinates with standard error
typically lying between 3 and 10 arcsec and 408-MHz flux densities
with standard error typically lying between 4 and 10 per cent.
Galactic coordinates, notes on source morphology and cross-references
to the Parkes Catalogues are included. The overall source density is
1500/sr, corresponding to 0.001 per beam area. There are 7347 sources
of listed flux density ≥ 1.00 Jy, at which level the catalogue is
substantially complete. The reliability is believed to be better than
99.9 per cent." The MRC was re-issued in 1990 with the original B1950
coordinates supplemented by J2000 values, and an additional
cross-reference flag `J' added to denote (extended) sources imaged at
843-MHz by P.A. Jones. No other alterations were made to the original
release. The MRC is now available on 5.25 inch, 1.2 Mbyte MS-DOS (IBM)
floppy disk (0.5 inch magnetic tape is also available, but is not the
preferred medium). In the floppy disk format, simple software is
provided to facilitate use of the catalogue on a PC computer.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
mrcj2000.dat 87 12141 Catalog Data
mrc.for 75 724 F77 code to read catalog by L. Cram (1990)
mrc.exe 80 693 MS-DOS executable from mrc.for
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Byte-by-byte Description of file: mrcj2000.dat
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Bytes Format Units Label Explanations
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1-9 A9 --- MRC *Recommended IAU name of the source based on
B1950 equinox.
11-12 I2 h RAh Right ascension (hours) in B1950 equinox
14-15 I2 min RAm RA (minutes) in B1950 equinox
17-20 F4.1 s RAs RA (sec) in B1950 equinox
22 A1 --- DE- Declination sign
23-24 I2 deg DEd DEC in degrees in B1950 equinox
26-27 I2 arcmin DEm DEC in arcminutes in B1950 equinox
29-30 I2 arcsec DEs DEC in arcseconds in B1950 equinox
32-33 I2 h RA2000h Right ascension (hours) in J2000 equinox
(Converted from B1950 using the STARLINK
program COCO)
35-36 I2 min RA2000m RA (minutes) in J2000 equinox
38-41 F4.1 s RA2000s RA (seconds) in J2000 equinox
43 A1 --- DE2000- Declination sign
44-45 I2 deg DE2000d DEC in J2000 equinox
47-48 I2 arcmin DE2000m DEC in J2000 equinox
50-51 I2 arcsec DE2000s DEC in J2000 equinox
52-54 F3.1 s e_RA2000s Standard error in RA (in seconds of time)
55 A1 --- n_RAs [*] scattering flag (1)
56-57 I2 arcsec e_DE2000s Standard error in Dec (in seconds of arc)
58 A1 --- n_DEs [*] scattering flag (1)
59-65 F7.2 Jy S408 Flux density
66-69 F4.2 Jy e_S408 Standard error
70 A1 --- n_S408 [*] scattering flag (1)
71- 73 A3 --- Mflag *[ AECMN] *Morphology flags
74- 76 A3 --- Cflag *[ CJMPRST] Cross-reference flags.
77-81 F5.1 deg GLON [0,360] Galactic longitude
82-87 F6.1 deg GLAT Galactic latitude
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Note (1): A `*' indicates that the values obtained from two or more
independent transits are scattered more than expected.
Note on MRC:
The first four characters are the hours and minutes of right
ascension, and the last four the signed declination in tenths of a
degree (unrounded). Column 9 contains the letters A, B, etc. denoting
sources having the same eight-character IAU designation but decreasing
flux density.
Note on Mflag: the Morphology flags are:
blank - no clear evidence of departure from point
A - Source with small-scale structure
E - Extended source
C - Complex extended source
M - Multiple sources (within 8 arcmin of another)
N - Weak neighbouring sources
Note on Cflag:
J - See Jones (1989, PhD, Sydney; published =1992ApJS...80..137J 1992ApJS...80..137J)
the 'J' is always in byte 74
P - Source lies within 2 arcmin of a Parkes source (catalog VIII/15)
T - Discussed in the original MNRAS MRC paper (1981MNRAS.194..693L 1981MNRAS.194..693L)
S - See Schilizzi and McAdam (1975MmRAS..79....1S 1975MmRAS..79....1S)
M - See Clarke et al. (1976AuJPS..40....1C 1976AuJPS..40....1C)
C - See Cameron (1971MNRAS.152..439C 1971MNRAS.152..439C)
R - See Robertson (1973AuJPh..26..403R 1973AuJPh..26..403R)
Two flags at most are used in Cols 75-76, with P>T>S>M>C>R.
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Data structure:
The machine-readable MRC is provided as 12141 ASCII records, each
of fixed length 87 bytes (each followed by CR,LF). The first line is
listed below, with `x' in positions that may be occupied by characters
but are blank in the first record :
1 10 20 30 40 50
| | | | | |
0000-506x 00 00 09.2 -50 41 31 00 02 42.5 -50 24 49x.3xx4xx
60 70 80
| | |
xx1.28x.06xxxxxpx-64.9 321.4
FORTRAN code to read MRC:
FORTRAN 77 source is included (mrc.for) to allow menu-driven reading of
the MRC as provided here. The FORTRAN program is self-explanatory. It
expects to find the MRC ASCII data file in the current directory and with
the name MRCJ2000. An executable version of this FORTRAN code has been
produced (using Microsoft FORTRAN Version 5, with a library which uses a
co-processor should one be available) and may be invoked on an IBM AT or
compatible by setting the correct current directory and typing `MRC'. The
program will run faster if the source and data are placed on a hard disk.
Historical Notes:
The original MRC was published in Mon. Not. R. astr. Soc., Vol 194,
pp 693-704 and Microfiches MN 194/1. (1981MNRAS.194..693L 1981MNRAS.194..693L)
(End) F. Ochsenbein [CDS], C.-H. Joseph Lyu [Hughes STX/NASA] 01-Aug-1995