CRATESOCRAP - OCRA-p Survey of a Subset of CRATES Sources
The selection criteria for the subsample of CRATES sources observed by the OCRA-p are given in Section 2 of the reference paper (q.v.). Plots of the measurements of each source over time and the aggregated source spectra between 26 MHz and 150 GHz are available online at the authors' web site: http://www.jodrellbank.manchester.ac.uk/research/ocra/crates/.
One Centimetre Receiver Array-prototype observations of the CRATES sources at 30 GHz Peel M.W., Gawronski M.P., Battye R.A., Birkinshaw, M., Browne I.W.A., Davis R.J., Feiler R., Kus A.J., Lancaster K., Lowe S.R., Pazderka B.M., Pazderski E., Roukema B.F., Wilkinson P.N. <Mon. Not. R.A.S. 410, 2690 (2011)> =2011MNRAS.410.2690P
The source designation in the generic style recommended by the Dictionary of Nomenclature of Celestial Objects, using the '[PGB2011]' prefix (for Peel, Gawronski, Battye 2011) and the J2000.0 equatorial coordinates truncated to 1 minute of time and 1 arcminute, e.g., '[PGB2011] J0954+7435'. No prefix is specified in the reference paper. By definition, these are all CRATES sources, but the CRATES source designation is higher precision in both coordinates: for example, the CRATES designation for this source is 'CRATES J095447+743549', hence the HEASARC created the '[PGB2011]' prefix.
The Right Ascension of the pointing for the 30-GHz observation in the selected equinox: this is that of the corresponding CRATES source, except for CRATES sources that have multiple components for which it is that of the brightest component. The position was given in J2000.0 equatorial coordinates to a precision of 0.1 seconds of time in the original table. For comparison, the OCRA beam is 1.2 arcminutes.
The Declination of the pointing for the 30-GHz observation in the selected equinox: this is that of the corresponding CRATES source, except for CRATES sources that have multiple components for which it is that of the brightest component. The position was given in J2000.0 equatorial coordinates to a precision of 0.1 arcseconds in the original table. For comparison, the OCRA beam is 1.2 arcminutes
The Galactic Longitude of the 30-GHz pointing.
The Galactic Latitude of the 30-GHz pointing.
The flux density of the corresponding source in the CRATES Catalog at 1.4 GHz, in mJy.
The flux density of the corresponding source in the CRATES Catalog at 4.8 GHz, in mJy.
The flux density of the corresponding source in the CRATES Catalog at 8.4 GHz, in mJy.
The flux density of the source at 30 GHz as measured by the OCRA-p, in mJy.
The uncertainty in the flux density of the source at 30 GHz as measured by the OCRA-p, in mJy. The methodology used for the OCRA-p flux density error calculation is discussed in Section 3 of the reference paper.
This parameter can contain flags with various notes on the source properties. From an inspection of the NVSS (Condon et al. 1998, AJ, 115, 1693), Faint Images of the Radio Sky at Twenty Centimeters (FIRST; Becker, White and Helfand 1995, ApJ, 450, 559) and CLASS (Browne et al. 2003, MNRAS, 341, 13; Myers et al. 2003, MNRAS, 341, 1) data, it is clear that the majority of the CRATES sources are unresolved. A number do, however, show extension and/or multiple components; these are marked with a flag value of 'e'. Sources where multiple components listed in CRATES have been merged together are denoted by 'NC', where 'N' is the number of components. WMAP sources (Gold et al. 2011, ApJS, 192, 15) are marked with a 'w', CJF sources (Taylor et al. 1996, ApJS, 107, 37; Lowe et al. 2007, A&A. 474, 1093) are marked with a 'c' and Fermi point sources (Abdo et al. 2010, ApJS, 188, 405) are marked with an 'f' (see Section 5 of the reference paper for a fuller discussion of these issues). Potential gigahertz-peaked spectrum (GPS) sources are marked with a 'g (see Section 6 of the reference paper for a fuller discussion). The authors also note that there are two CLASS lens systems within the sample, J1609+6532 and J1938+6648 (Browne et al. 2003, MNRAS, 341, 13).
There are 42 sources that appear variable within the OCRA measurements; these are marked with a 'v'. Sources were identified as variable if they were reasonably strong (> 20 mJy) and had two measurements which were 25% higher than the mean. Although sources with two measurements that are 25% lower than the mean could also be variable sources, these would be more contaminated by any sources with measurements that suffer from bad telescope pointing (and hence a reduced measured flux density) that have not been flagged. As such, the authors did not include these in the list of variable sources.