Detailed Description of Catalogue VIII/16/

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VIII/16     Molonglo Reference Catalogue of Radio Sources (Large+ 1991)
Molonglo Reference Catalogue of Radio Sources
    Large M.I., Cram L.E., and Brugess A.M.
    <The Observatory, 111, 72 (1991)>
     =1991Obs...111...72L     (SIMBAD/NED RefCode)
ADC_Keywords: Radio sources

    "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:

FileName Lrecl Records Explanations
ReadMe 80 . This file mrcj2000 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
Byte-by-byte Description of file: mrcj2000
Bytes Format Units Label Explanations
1- 9 A9 --- Bname *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 RAh2000 Right ascension (hours) in J2000 equinox (Converted from B1950 using the STARLINK program COCO) 35- 36 I2 min RAm2000 RA (minutes) in J2000 equinox 38- 41 F4.1 s RAs2000 RA (seconds) in J2000 equinox 43 A1 --- DE-2000 Declination sign 44- 45 I2 deg DEd2000 DEC in J2000 equinox 47- 48 I2 arcmin DEm2000 DEC in J2000 equinox 50- 51 I2 arcsec DEs2000 DEC in J2000 equinox 52- 54 F3.1 s e_RAs2000 Standard error in RA (in seconds of time) 55 A1 --- n_RAs [*] scattering flag (1) 56- 57 I2 arcsec e_DEs2000 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
Note (1): A `*' indicates that the values obtained from two or more independent transits are scattered more than expected. Note on Bname: 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) 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) S - See Schilizzi and McAdam (1975MmRAS..79....1S) M - See Clarke et al. (1976AuJPS..40....1C) C - See Cameron (1971MNRAS.152..439C) R - See Robertson (1973AuJPh..26..403R) Two flags at most are used in Cols 75-76, with P>T>S>M>C>R.
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) ================================================================================ (End) F. Ochsenbein [CDS], C.-H. Joseph Lyu [Hughes STX/NASA] 01-Aug-1995
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