The z < 1.0 catalogue: field information

This page gives information on each of the different fields in the online catalogue.

3CRR name

This is the name by which the radio source is most commonly known. The 3CRR catalogue includes several sources which were missed in the original 3C surveys, either because of low surface brightness or due to their proximity to other bright objects. These objects are listed with their names from other catalogues, typically radio names from the 4C catalogue (e.g. 4C14.11).

In the database page the name field is a link to the source page which shows all information about a given source.


This is the redshift from the 3CRR catalogue.

178-MHz flux

This is the total source flux density from 3CRR. The flux densities have been corrected to the standard flux scale of Baars et al. (1977). They are therefore different by a factor 1.09 from the fluxes in the original 3CRR paper.

Spectral index

This is the spectral index of the whole source between 178 and 750 MHz.


For each source we tabulate properties of a high-resolution map (showing details of the core, jets and hotspots) and a low-resolution map (ideally containing all the flux density from the source in the lobes). We tabulate properties of both maps. Sometimes the same map was used for all source measurements, in which case the two maps will have the same properties.

When physical quantities are tabulated, all flux densities are corrected from the observed frequency to a standard (lab-frame) frequency of 8.4 GHz.

Total flux density

This is the flux density measured from the low-resolution map.

Core flux density

This is the core flux density measured from the high-resolution map. Note that cores may be variable; we only tabulate a single value.


Prominences are defined as the ratio of the luminosity density of the component at the standard frequency (8.4 GHz) to the luminosity density of the whole source at 178 MHz. We choose to define prominence this way because total flux densities measured from the high-frequency maps may not be accurate if the map does not sample short enough baselines.