Surveys: Automated Surveys of bright galaxies

The APM Bright galaxy surveys, compiled from UKST IIIa-J plates scanned by the Automated Photographic Measuring (APM) facility at Cambridge, consist of two catalogues of galaxies:

  • The APM Hydra-Centaurus survey of galaxies brighter than BJ=17 magnitude compiled from 110 UKST plates northward of Galactic latitude b=10 degrees. This survey includes the densest part of the Supergalactic plane, covering the Shapley and Hydra-Centaurus Superclusters.
  • The ACCESS (APM-Cambridge Catalogue of the Equatorial Southern Strip) survey of galaxies either brighter than BJ=17 magnitude or larger than 0.5 arcmin, compiled from 200 UKST plates. This survey covers almost the entire southern Equatorial region of the sky (Declination +2.5 deg to -17.5 deg), except 20 degrees on either side of the Galactic Plane. This is the first homogeneous catalogue of bright galaxies in the Equatorial strip, a region that was missed by the two most frequently-used sources of galaxies larger than 1 arcmin, the ESO and UGC catalogues. This "missing strip" has always been a problem for all-sky surveys. This survey (in collobaration with D. Lynden-Bell, University of Cambridge), will be published by Cambridge University Press in 2001.

There is an overlap of 26 plates between the two surveys. The plates are matched from overlaps and photmetrically calibrated using CCD images of galaxies on most plates.

These catalogues are being used as source catalogues of various other surveys, like the FLASH redshift survey and the 6dF redshift survey. They are also being used to analyze various statistics of the distribution of galaxies, e.g. their morphological content, luminosity distribution and clustering statistics.

Researcher: Somak Raychaudhury


Galaxies brighter than 17th magnitude in the northern half of the APM Bright galaxies surveys. There are 27,500 galaxies in this plot: about 20% of them would have been previously catalogued. They were found by an automated procedure from digitized scans of IIIa-J plates obtained by the 1.2m UK Schmidt Telescope in Australia. Each object has been inspected by eye and verified to be a galaxy. The obvious concentration in the plot is the Shapley Supercluster.