RT9CC15GHZ ivo://nasa.heasarc/rt9cc15ghz NASA/GSFC HEASARC Waldram et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source The 9C (9th Cambridge) survey of radio sources with the Ryle Telescope at 15.2 GHz was set up to survey the fields of the cosmic microwave background telescope, the Very Small Array (VSA). In their first paper (Waldram et al. 2003, MNRAS, 342, 915), the authors described three regions of the survey, constituting a total area of 529 deg<sup>2</sup> to a completeness limit of ~ 25 mJy. In this follow-up, they present results from a series of deeper regions, constituting a total area of 115 deg<sup>2</sup> complete to ~ 10 mJy and of 29 deg<sup>2</sup> complete to ~ 5.5 mJy. The authors have investigated the source counts and the distributions of the 1.4 to 15.2 GHz spectral indices for these deeper samples. The whole catalog of 643 sources is contained in the present table. Down to their lower limit of 5.5 mJy, the authors detect no evidence for any change in the differential source count from the earlier fitted count above 25 mJy, n(S) = 51(S/Jy)<sup>-2.15</sup> Jy<sup>-1</sup> sr<sup>-1</sup>. They matched both their new and earlier catalogues with the NRAO VLA Sky Survey (NVSS) catalogue at 1.4 GHz and selected flux-limited samples at both 15 and 1.4 GHz. As they expected, they found that the proportions of sources with flat and rising spectra in the samples selected at 15 GHz are significantly higher than those in the samples selected at 1.4 GHz. In addition, for 15-GHz samples selected in three flux density ranges, they detect a significant shift in the median value of the 1.4 to 15.2 GHz spectral index: the higher the flux densities, the higher the proportions of sources with flat and rising spectra. In the area complete to ~ 10 mJy, the authors find five sources between 10 and 15 mJy at 15 GHz, amounting to 4.3 per cent of sources in this range, with no counterpart in the NVSS catalogue. This implies that, had they relied on the NVSS for locating their sources, they could have missed a significant proportion of them at low flux densities. These results illustrate the problems inherent in using a low-frequency catalog to characterize the source population at a much higher frequency and emphasize the value of a blind 15.2-GHz survey. This table was created in November 2010 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/404/1005">CDS catalog J/MNRAS/404/1005</a> file 9c_cont.dat. This is a service provided by NASA HEASARC . 2010MNRAS.404.1005W https://heasarc.gsfc.nasa.gov/W3Browse/all/rt9cc15ghz.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=rt9cc15ghz& GET text/xml 180 99999 true 47.22208333 24.49055556 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=rt9cc15ghz GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_rt9cc15ghz&Action=More+Options&Action=Parameter+Search&ConeAdd=1 RADIO CATALOG 0.0166666666666667 Radio public rt9cc15ghz 9C Continued 15-GHz Ryle Telescope Survey of VSA Fields Source C name Source Designation (9C JHHMM+DDMMa) meta.id;meta.main char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable flux_2_cm 15.2-GHz Flux Density from Subsequent Pointed Observation mJy phot.flux.density;em.radio.12-30GHz double nullable date_observed Date of Observation mjd time.epoch;obs int nullable deep_flag Flag [D] Indicates Detection in a Deeper Survey Regions Complete to ~5.5 mJy meta.note;obs char nullable source_flag Flag [be] Indicates Binary/Extended Source Morphology meta.code;src.morph char nullable lii Galactic Longitude degree pos.galactic.lon double nullable bii Galactic Latitude degree pos.galactic.lat double nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable