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1985A&AS...59..255Ficarra+
See also BOLOGNA 2
Bologna Sky Survey at 408 MHz (B3) (Dec=37 to 47deg)
Description
This catalogue contains the first section of a sky survey performed at
408 MHz with the 'Northern Cross' Radiotelescope. It contains 13,354
radiosources. Although sources down to about 70 mJy were measured,
only sources brighter than 0.10 Jy are retained in the catalogue.
According to an estimate of confusion errors, this corresponds to a
detection threshold of about 5 sigma. The list is meant to include
all the sources with a measured flux S > 0.10 Jy, in the sky area
included between the declinations +37 15 and +47 37, epoch 1978.0.
The angular resolution of the catalog is 2.6' x 4.8' (at Dec=45.5d).
A number of zones however are affected by interferences, malfunctions,
etc. The principal one is centered about the radiosource Cyg A, which
is itself in the map, but not in the catalogue. The zone between RA
19 30 to 20 30 is entirely lacking, due to strong confusion. In the
zone from 19 00 to 19 30 and from 20 30 to 21 00, only sources
brighter than 0.75 Jy are listed, and to this level the catalogue is
expected to be complete. For detailed discussion of the completeness
of the catalogue see the original publication: Ficarra et al., 1985,
Astronomy and Astrophysics Supplement Series, 59, 255.
1 name Name of source (char9, example: '0003+408B')
2 ra_rad radians Right ascension of source in radians (B1950) (real, example: 0.016)
3 dec_rad radians Declination of source in radians (B1950) (real, example: 0.712)
4 ra_deg degrees Right ascension of source in degrees (B1950) (real, example: 0.935)
5 dec_deg degrees Declination of source in degrees (B1950) (real, example: 40.812)
6 flux Jy Flux density at 408 MHz (real, example: 0.140)
7 fit Goodness of the fit (real, example: 0.90)
8 rel_code Reliability code (char4, example: '0201')
9 src_sep Source separation code (char5, example: 'D3.5B')
10 xpix X pixel in sky image (real, example: 78.2) (valid range: 0-450)
11 ypix Y pixel in sky image (real, example: 270.0) (valid range: 0-450)
1. COLUMN name
This column gives the B3 name of the source, obtained by combining the
hours and minutes of right ascension with the declination truncated to
tenths of degrees. If necessary, a letter is added at the end to
distinguish between sources with similar positions. For example,
sources at 23h 55m 01.9s, 47d 10' 01" and 23h 55m 34.8s, 47d 09' 36"
would be named 2355+471A and 2355+471B.
Example (name) (char9): '0003+408B'
2. COLUMNS ra_rad dec_rad ra_deg dec_deg
The first two columns list the right ascension and declination of the
source (epoch 1950) in radians. The second two columns list the same
position in degrees.
Example (ra_rad) (real): 0.016
Example (dec_rad) (real): 0.712
Example (ra_deg) (real): 0.935
Example (dec_deg) (real): 40.812
3. COLUMN flux
This column gives the total source flux density in Jy, as given by the
source measuring algorithm. In the large majority of cases, this is
practically equivalent to the peak flux density.
Example (flux) (real): 0.140
4. COLUMN fit
This entry describes the goodness of the fitting algorithm, related to
the rms value of the residuals in the fitting matrix. Values range
from 0.0 to 13.2 and allow an estimate of the flux density error. See
the paper for full details of this quantity.
Example (fit) (real): 0.90
5. COLUMN rel_code
This column gives a four digit code indicating source reliability. An
algorithm was devised by which every source was marked with a
four-digit number n1, n2, n3, n4 with each digit indicating a separate
reason for problems, as follows:
n1 : a disturbing, strong source is present, very close either in
R.A. or in DEC. The flux ratio R is indicated by n1 and is n1 = R/10,
truncated to the integer.
n2 : if non-zero, it indicates that the source lies in the vertical
part of the cross-shaped area, and in the position of a grating
response in N-S. It thus indicates a larger chance for the source
to be spurious. The value itself is the rank of the grating response
(n2 = 5 means the grating closer to the source, etc. down to n2 = 1).
n3 : if non-zero it means that the source is very close to a very
strong source, although not in the cross-shaped area mentioned above.
A circular area is defined with radius r = 2.8 sqrt(R) pixels; n3
indicates how close the source is to the disturbing source, in units
of 1/r.
n4 : if n4 > 4, it indicates that the source lies within a disturbed
area with the following code: 5 = solar interferences; 6 = sidelobes
of Cyg A; 7 = supernova remnant G160.4+2.8 (Felli et al., 1977);
8 = supernova remnant G166.0+4.3 (Willis, 1973); 9 = man-made
interferences. If n4 < 4, it indicates that n4 (and no more)
disturbing sources are present. In this case the previous digit
refers to the stronger disturbing source.
Example (rel_code) (char4): '0201'
6. COLUMN src_sep
This column gives a string for those sources measured by the double
source algorithm. Sources separated by less than one pixel are given
as a single source, marked with an "R" in the first column (for
Resolved). When both components are listed separately, they are
marked with a "D" in the first column (for Double). In both cases,
the following figure is the separation in arcmin. For double sources,
an "A" or a "B" is appended to the string to mark the two components
which belong together.
Example (src_sep) (char5): 'D3.5B'
7. COLUMNS xpix ypix
These columns give the X and Y pixel position of the source in the sky image.
Example (xpix) (real) (valid range: 0-450): 78.2
Example (ypix) (real) (valid range: 0-450): 270.0
References
Felli M., Tofani G., Fanti C., Tomasi P., 1977, Astron. Astrophys.
Suppl. Ser., 27, 181.
Ficarra, A., Grueff, G., Tomassetti, G., 1985, Astron. Astrophys. Suppl.
Ser., 59, 255.
Willis A.G., 1973, Astron. Astrophys., 26, 237.
Origin submitted by G. Grueff
Columns 11 Rows 13354
For catalog content:
D. E. Harris, SAO; harris@cfa.harvard.edu (7/92)