ACDS V10.0 - Thu May 09 20:07:10 CEST 2019
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Detailed Description of VIII/84 :
A final non-redundant catalogue for 7C 151-MHz survey (Hales+ 2007)
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Note : this is the description file of the original catalog.
This HTML page corresponds well to the original description, but some minor
changes in the format may have been introduced in the FITS output
files in order to allow for arithmetic operations on quantities
such as coordinates and times. h:m:s and d:m:s units are normally
converted into degrees, and YYYY-MM-DD into julian days.
Similarly, some slight changes may have been introduced in the
units; the value given in the HTML files supersedes the value indicated in the ReadMe
file for this catalogue.
VIII/84 A final non-redundant catalogue for 7C 151-MHz survey (Hales+ 2007)
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A final non-redundant catalogue for the 7C 151-MHz survey
Hales S.E.G., Riley J.M., Waldram E.M., Warner P.J., Baldwin J.E.
<Mon. Not. R. Astron. Soc. 382, 1639 (2007)>
=2007MNRAS.382.1639H
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ADC_Keywords: Radio sources ; Surveys
Keywords: catalogues - surveys - radio continuum: general
Description:
We present a final unified catalogue for the 7C survey at 151 MHz with
resolution 70x70cosec(dec) arcsec2. This has been constructed by
amalgamating the existing catalogues derived from individual fields
imaged at this resolution and eliminating redundancy in regions of
mutual overlap. This is a non-trivial procedure because the flux in
multiple-component sources may be fitted differently on alternative
images, owing, for example, to differences in local noise and beam
distortion. The final catalogue thus produced contains 43683 sources.
Separate final catalogues have been published for the 7C Galactic
Plane survey (7CG, see Cat. J/MNRAS/294/607) and the lower-resolution
survey of the low-declination strip 9h<RA<16h, 20deg<Dec<35deg (Cat.
J/MNRAS/282/779).
The individual catalogues for about 40 of the regions contributing to
the total have already been published, together with full details of
the methodology, in MNRAS or A&AS:
Lacy et al. 1995, MNRAS, 276, 614 (=1995MNRAS.276..614L) (#92 below)
Visser et al. 1995, A&AS, 110, 419 (=1995A&AS..110..419V) (#93 below)
Pooley et al. 1998, MNRAS, 298, 637 (=1998MNRAS.298..637P) (#94-96 below)
Riley et al. 1999, MNRAS, 306, 31 (=1999MNRAS.306...31R) (# 1-33 below)
and these data are also available via the MRAO website at
http://www.mrao.cam.ac.uk/surveys/7C/
Individual catalogues for the remaining 58 regions by Riley et al.
(#34-91 below) were released electronically via the MRAO website in
November 2001. These include a re-analysis of data originally
published in rather a different parametrization by McGilchrist et al.
1990, MNRAS, 246, 110 (=1990MNRAS.246..110M) The regions re-analyzed
are those numbered #41,44,59,60,62 and 63 below and they supersede
McGilchrist's 1990 publication.
The RAxDec coverage, average rms noise, flux density of the faintest
source listed and completeness limit for each of the individual
regions contributing to the final catalogue are given in the table
"regions.dat".
1-sigma errors on the listed source positions may be approximated by:
RA..error(arcsec) = SQRT(1.0**2 + (32/SNR)**2)
Dec.error(arcsec) = Kcosec(dec) x (RA error)
where (approx) K= 1.0 around dec 70, increasing to 1.3 below dec 50,
and 1-sigma errors on the listed flux densities may be approximated by:
Error on S beam-fitted(Jy) = SQRT(0.03**2 + SNR**-2) x S(Jy)
Error on SINT(Jy) = 1.5 x SQRT(0.03**2 + SNR**-2) x SINT(Jy)
where SNR, S and SINT correspond to the columns denoted by those names
in the byte-by-byte description below. For multi-component sources the
SNR for the brightest component is used to estimate the SINT error.
For further details of the surveys and data analysis procedures please
refer to the published papers referenced at the head of this file and
references therein.
File Summary:
FileName Lrecl Records Explanations
× 80 . This file
× ReadMe 80 . This file
× 7c.dat 86 43683 7C sourcelist of 43683 sources
× regions.dat 52 96 List of fields observed
See also:
J/MNRAS/282/779 : 7C: 151-MHz survey of region 9-16h 20-35deg (Waldram+ 1996)
J/MNRAS/294/607 : 7C(G) 151MHz survey of the Galactic plane (Vessey+ 1998)
Nomenclature Note:
Sources of the 7C catalogue should be designated with their full
B1950 beam-fitted position with 'format' 7C HHMMSS.s+DDMMSS, e.g.
7C 001920.0+451334
Byte-by-byte Description of file: 7c.dat
Bytes Format Units Label Explanations
1- 2 I2 h RAh Beam-fitted position right ascension B1950
4- 5 I2 min RAm Beam-fitted position right ascension B1950
7- 10 F4.1 s RAs Beam-fitted position right ascension B1950
12 A1 - DE- Beam-fitted position declination (sign)
13- 14 I2 deg DEd Beam-fitted position declination B1950
16- 17 I2 arcmin DEm Beam-fitted position declination B1950
19- 20 I2 arcsec DEs Beam-fitted position declination B1950
24- 25 I2 h RAIh Centroid position right ascension B1950
27- 28 I2 min RAIm Centroid position right ascension B1950
30- 33 F4.1 s RAIs Centroid position right ascension B1950
35 A1 - DEI- Centroid position declination (sign)
36- 37 I2 deg DEId Centroid position declination B1950
39- 40 I2 arcmin DEIm Centroid position declination B1950
42- 43 I2 arcsec DEIs Centroid position declination B1950
47- 52 F6.3 Jy S Beam-fitted flux density, in Jy/beam
54- 59 F6.3 Jy Sint Integrated flux density
61- 65 F5.1 --- SNR Signal-to-noise ratio
67- 70 F4.1 --- Extent Extent of the source
in units of local beam area
74 I1 --- Nmax *Number of local maxima within the
integrated region
76- 79 I4 --- ICOMP *Serial number identifying complex source
(set to 0 if Nmax=1)
81- 86 I06 --- Map *Field from which data record originates
Note on Nmax and ICOMP:
ICOMP is a serial number denoting a particular complex source - it
has the same value for all the Nmax components (local maxima) which
belong to that particular source, allowing the user to associate
its individual components listed in the catalogue, no matter how
the catalogue is ordered. Nmax specifies the total number of components.
For a source with only one component Nmax=1 and ICOMP is set to 0
Note on Map:
Field from which data record originates with + sign excluded,
e.g. Map 072245 denotes the region 0722+45
Byte-by-byte Description of file: regions.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Reg Region number
4- 9 I06 --- Map Name of map
11 A1 --- r_Map [*a-e] Origin of the region data (1)
14- 15 I2 h RA1.h Coverage RA1-RA2xDE1-DE2 B1950 (2)
17- 18 I2 min RA1.m Coverage RA1-RA2xDE1-DE2 B1950 (2)
20 A1 --- --- [-]
22- 23 I2 h RA2.h Coverage RA1-RA2xDE1-DE2 B1950 (2)
25- 26 I2 min RA2.m Coverage RA1-RA2xDE1-DE2 B1950 (2)
27 A1 --- DE1.- Coverage RA1-RA2xDE1-DE2 B1950 (2)
28- 29 I2 deg DE1.d Coverage RA1-RA2xDE1-DE2 B1950 (2)
31- 32 I2 arcmin DE1.m Coverage RA1-RA2xDE1-DE2 B1950 (2)
34 A1 --- --- [-]
35 A1 --- DE2.- Coverage RA1-RA2xDE1-DE2 B1950 (2)
36- 37 I2 deg DE2.d Coverage RA1-RA2xDE1-DE2 B1950 (2)
39- 40 I2 arcmin DE2.m Coverage RA1-RA2xDE1-DE2 B1950 (2)
43- 44 I2 mJy Noise Average rms noise before primary beam
correction
46- 48 I3 mJy Sfaint Flux density of the faintest source listed
50- 52 I3 mJy Scomp Completeness limit
Note (1): Origin for the region data as follows:
a = from Riley et al. 1999MNRAS.306...31R (1-33)
b = from Riley et al. 2001: 58 regions at (34-91)
www.mrao.cam.ac.uk/surveys/7C/
c = from Lacy et al. 1995MNRAS.276..614 (92)
d = from Visser et al. 1995A&AS..110..419 -
an amalgamation of seven pointings (93)
e = from Pooley et al. 1998MNRAS.298..637 (94-96)
* = 150056 corrupted replaced by 150060
(an amalgamation of data from unpublished regions 144060, 152060)
Note (2): RA coverage is indicated by approx RA range at Dec of field centre.
Dec coverage is indicated by approx Dec range at RA of field centre.
History:
* 24-Jan-2008: a spurious negative value of Nmax in row 28028 of
7c.dat was corrected on 24-Jan-2008
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(End) Sally Hales [MRAO] 25-Jan-2008