The Ninth Cambridge (9C) Survey of Radio Sources
The 9C survey of radio sources was made with the Ryle Telescope at a frequency of 15.2 GHz and a resolution of 25 x 25 cosec(dec) arcsec2.
It was set up as part of the observing strategy of the Very Small Array (VSA) and its prime motivation was to define a catalogue of the foreground sources to be monitored by the VSA during its observations of the cosmic microwave background. It is, however, of much wider interest, being the first survey to cover an appreciable area at a comparable radio frequency.
The regions surveyed correspond to the fields chosen for the VSA observations, rather than forming one large contiguous area. Two data releases are now available:
9C Data Release 1
Waldram, E.M., Pooley, G.G., Grainge, K.J.B., Jones, M.E., Saunders, R.D.E., Scott, P.F., Taylor, A.C., 2003, MNRAS, 342, 915
comprises three circular regions covering a total area of 520 deg2 with a completeness limit of 25 mJy. Details of the regions are specified in the table below.
|Field name||RA, Dec of centre (J2000)||Radius||No. of sources|
|0020p30.dat||00h 17m 36.5s 30° 16′ 39″||5.5°||84|
|0940p32.dat||09h 40m 57.7s 31° 46′ 21″||6.0°||103|
|1540p43.dat||15h 36m 42.7s 43° 20′ 11″||5.0°||55|
Radio and optical follow-up
Radio and optical follow-up investigations have been carried out for 176 of the catalogued sources. For full details see:
Bolton, R.C., Cotter, G., Pooley, G.G., Riley, J.M., Waldram, E.M., Chandler, C.J., Mason, B.S., Pearson, T.J., Readhead, A.C.S., 2004, MNRAS, 354, 485
you can also access the NED plots of radio spectra published in this paper as gzipped postscript files .
9C Data Release 2
This is a deeper survey, driven as before by the source-monitoring requirements of the VSA observation programme.
It comprises seven fields, each delineated by boundaries in RA and Dec, together covering a total of 114.7 deg2 for which the source catalogue is complete to ~ 10 mJy. Within in each of these fields are a number of more sensitive areas – amounting to 29.1 deg2 in total – for which completeness to ~ 5.5 mJy is achieved. The accompanying 2-page document tabulates the RA and Dec specifications of the seven major fields and those of the more sensitive the sub-areas within them, and provides figures illustrating the layouts.
Last modified 19 May 2010