RTV9C15GHZ - 9C 15-GHz Ryle Telescope Survey of VSA Fields Source Catalog

Overview

The fields chosen for the first observations of the cosmic microwave background (CMB) with the Very Small Array (VSA) have been surveyed with the Ryle Telescope at 15 GHz. The authors have covered three regions around RA = 00^h20^m and Dec = +30^o, RA = 09^h40m and Dec = +32^o and RA = 15^h40^m and Dec = +43^o (J2000.0), comprising an area of 520 deg². There are 465 sources in this entire area which are above the estimated completeness limit of ~ 25 mJy, although a total of ~ 760 sources were detected, some as faint as 10 mJy.

The prime motivation of this study was to define a catalog of the foreground sources that must be monitored by the VSA during its observations at 34 GHz. In particular, it provides a means of identifying GigaHertz peaked spectrum (GPS) sources, which are important for the study of radio source evolution, as well as being a significant foreground for CMB observations over a range of wavelengths. Since this will be a new and quite extensive survey, it was desgignated as '9C' or the Ninth Cambridge survey.

For the purpose of this particular component of the 9C survey, the authors designated as a subset, 3 circular areas, VSA1, VSA2 and VSA3, defined by the properties listed in Table 2 of the reference paper and reproduced below:

Field      Centre J2000.0         Center B1950.0      Radius     Area
           RA         Dec         RA         Dec     (degrees)  (sq. degrees)

VSA1    00 17 36.5 +30 16 39   00 15 00.0 +30 00 00   5.5        95.0
VSA2    09 40 57.7 +31 46 21   09 38 00.0 +32 00 00   6.0       113.0
VSA3    15 36 42.7 +43 20 11   15 35 00.0 +43 30 00   5.0        78.5

There are 242 sources which were both above the 25 mJy completeness limit and were in the 286.5 deg² contained within these 3 circular fields. These source were listed in 3 tables in the reference paper, Table 4 (VSA1), Table 5 (VSA2) and Table 6 (VSA3). These have been combined into this one HEASARC table, in which the HEASARC added a new parameter vsa_field, which is set to 1 for the VSA1 sources, 2 for the VSA2 sources, and 3 for the VSA3 sources.

Catalog Bibcode

2003MNRAS.342..915W

References

9C: a survey of radio sources at 15 GHz with the Ryle Telescope.
    Waldram E.M., Pooley G.G., Grainge K.J.B., Jones M.E., Saunders R.D.E.,
    Scott P.F., Taylor A.C.
   <Mon. Not. R. Astron. Soc. 342, 915 (2003)>
   =2003MNRAS.342..915W

Provenance

This table was created in November 2010 based on CDS catalog J/MNRAS/342/915 files table4.dat, table5.dat and table6.dat.

HEASARC Implementation

The radio source '9C J0019+2817' was listed in both the published and electronic versions of table 4 in the reference paper as having been observed on YY/MM/DD = 00/00/01. The HEASARC has changed this date to what we assume the authors meant, viz., 00/01/01, but we have no independent confirmation of the accuracy of this assumption.

Parameters

Name
The position-based source designation adopted by the HEASARC, viz., '9C JHHMM+DDMMa', where the numerical part of the name is the truncated J2000.0 position of the radio source. There was one case ('9C J1000+2752') in which two independent sources were given the same source name in the original table; the HEASARC added an a 'a' to the name of the source at (RA, Dec) = 10^h 00^m 07.6^s, +27^o 52' 46" (J2000.0) and a 'b' to the name. of the source at RA, Dec) = 10^h 00^m 29.4^s, +27^o 52' 12" (J2000.0) in order to differentiate these 2 names.

RA
The Right Ascension of the 15.2-GHz radio source in the selected equinox. This was given in J2000.0 equatorial coordinates in the original table to a precision of 0.1 seconds of time. The position of a source was derived from a raster map, unless the follow-up pointed observation indicated a significant difference, in which case the latter position is substituted. The authors have checked the positions of 19 sources which appeared on more than one raster map, and estimate that the positional accuracy is better than 10 arcseconds. For bright sources, the positions are espected to be accurate to <~ 3 arcseconds, as estimated from the observations of the 17 sources in the VSA2 field which were also found in the Jodrell VLA calibrator survey.

Dec
The Declination of the 15.2-GHz radio source in the selected equinox. This was given in J2000.0 equatorial coordinates in the original table to a precision of 1 arcsecond. The position of a source was derived from a raster map, unless the follow-up pointed observation indicated a significant difference, in which case the latter position is substituted. The authors have checked the positions of 19 sources which appeared on more than one raster map, and estimate that the positional accuracy is better than 10 arcseconds. For bright sources, the positions are espected to be accurate to <~ 3 arcseconds, as estimated from the observations of the 17 sources in the VSA2 field which were also found in the Jodrell VLA calibrator survey.

LII
The Galactic Longitude of the 15.2-GHz radio source.

BII
The Galactic Latitude of the 15.2-GHz radio source.

Flux_2_cm
The flux density of the 15 GHz (2 cm) radio source, in mJy. (These values were converted by the HEASARC from the Jy units used in the original table). The uncertainty in the flux densities is dominated by the random uncertainty in the flux calibration, which is estimated to be ~ 5 per cent

Date_Observed
The date of the pointed observation of the source. This information is included because a number of the sources are highly variable.

Vsa_Field
The VSA field number in whch the source is situated. These source were listed in 3 tables in the reference paper, Table 4 (VSA1), Table 5 (VSA2) and Table 6 (VSA3). These have been combined into this one HEASARC table, in which the HEASARC added this new parameter, which is set to 1 for the VSA1 sources, 2 for the VSA2 sources, and 3 for the VSA3 sources.

Contact Person

Questions regarding the RTV9C15GHZ database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:34:14 EDT