The Parkes Catalogue of Radio Sources Declination Zone +20° to +27°

Abstract

SummaryThis paper gives details of 397 radio sources between declina.tions + 20 0 and +27 0 which were compiled from a finding survey made at 635 MHz with the 210 ft reflector at the Australian National Radio Astronomy Observatory, Parkes, N.S.W.The survey covers an area of 0·703 steradian but is incomplete in two regions within ± 100 of the galactic equator. Additional measurements of flux densities and positions were made at 1410 and 2650 MHz. Some discussions on spectra, source counts, and source identifications are included, and a comparison is made between this survey and other published oatalogues oovering the same region. I. INTRODUOTIONThis paper is the fifth seotion of a survey for radio souroes being made with the 210 ft radio telescope at the Australian National Radio Astronomy Observatory, Parkes, N.S.W. The earlier parts of the survey have already been published and oover the declination zones 0° to +20° ), 0° to -20° (Shimmins et al. 1966), -20° to _60° (Bolton, Gardner, and Maokey 1964, and _60° to _90° (Prioe and Milne 1965). The present paper oovers the remaining deolination zone that is visible with the Parkes telesoope, +20° to +27°, and is oomplete except for two areas within ±10 0 of the galactio equator. The oatalogue oontains 397 souroes within O· 703 steradian, 341 of these souroes being outside the region ± 10° of the galaotio equator (effeotive area 0·606 steradian). The oatalogue is thought to be substantially oomplete down to a flux density of 1·5 f.u.t at 635 MHz outside the galaotio plane region but oontains some weaker souroes down to 0·8 f.u.The observations differ from those of the earlier seotions of the oatalogue in that the finding survey was done at a frequenoy of 635 MHz. Positions and flux densities were subsequently measured at 1410 and 2650 MHz.The estimated r.m.s. errors in position and the date of measurement are given for eaoh souroe in the oatalogue.

The Molonglo Southern 4 Jy Sample (MS4). I. Definition

“…In assessing the completeness of their sample, BRL99 have misguidedly used the PKSCAT90 compilation (Otrupcek & Wright 1991) rather than the original Parkes catalogs Shimmins et al 1966;Day et al 1966). Most of the 408 MHz flux densities listed by PKSCAT90 are not Parkes measurements at all but are taken directly from the MRC.…”

“…We searched the literature for flux density measurements at 408 MHz for these 97 sources. If such measurements were unavailable, we used the radio spectrum or unpublished Molonglo 408 MHz Day et al 1966; (7) Shimmins et al 1966;(8) Shimmins & Day 1968;(9) Bolton et al 1979 and references therein; (10) Large et al 1981;(11) Griffith et al 1994;(12) Wright et al 1994;(13) Griffith et al 1995;(14) Wright et al 1996. data. As a result of these estimates, described in x 2.3, 20 extended sources were added to the sample, bringing the total number of sources to 228.…”

Improved Positions and Some Optical Identifications for 451 4C Radio Sources Between Declinations 4° and 20°

“…Accurate positions of many of the stronger sources which are also listed in the Parkes catalogue of radio sources (Shimmins and Day 1968;Division of Radiophysics, CSIRO 1969) have already been measured and optical identifications secured where possible. The positions of many of the weaker 4C sources north of declination 20° have been determined by Olsen (1967) and positions for the weaker sources between declinations 4° and _4° are currently being measured by J. V. Wall and A. J. Shimmins with the Parkes telescope.…”

Identification of Radio Sources Between Declinations +27° and ?30°

“…The selection list for the position measurements comprised all sources in the Parkes catalogue for declinations +20° to +27° (Shimmins and Day 1968) with flux densities at 2650 MHz ~ 0·8 flux units and all sources north of _33° in the more southerly zones of the Parkes catalogue with flux densities at 2650 MHz ~ 0·8 flux units that had not been previously measured by Shimmins, Clarke, and Ekers (1966). In addition, some sources with spectral indices flatter than -0·5 and flux densities between 0·5 and 0·8 flux units were included.…”