APM Galaxy Survey

APM Galaxy Survey The APM Galaxy Survey was a large photographic catalogue of galaxies compiled from digitized Schmidt photographic plates using the Automatic Plate Measuring (APM) machine at the Institute of Astronomy, Cambridge and associated with projects and institutions including the Anglo-Australian Observatory, Royal Observatory, Edinburgh, Cambridge University, and collaborations with observers from Palomar Observatory, Mount Palomar, and the European Southern Observatory. It provided angular positions, magnitudes, and morphological parameters that underpinned statistical studies connecting results from the Two Micron All Sky Survey, the Sloan Digital Sky Survey, the 2dF Galaxy Redshift Survey, and the IRAS Point Source Catalogue to cosmological analyses drawing on datasets like Wilkinson Microwave Anisotropy Probe and Planck (spacecraft).

Overview

The project originated from efforts by teams at the Institute of Astronomy, Cambridge, the Royal Observatory, Edinburgh, and the Anglo-Australian Observatory to digitize the photographic archive of the UK Schmidt Telescope; it used the Automatic Plate Measuring machine to scan Schmidt plates from the Southern Sky Survey and the Palomar Observatory Sky Survey and to produce a catalogue used alongside the COSMOS (machine), the Digitized Sky Survey, and follow-up campaigns by groups at the Royal Greenwich Observatory, the University of Oxford, and the Max Planck Institute for Astrophysics. Funding and logistical support involved organisations such as the Science and Engineering Research Council, the Royal Society, and collaborations with astronomers affiliated with Harvard-Smithsonian Center for Astrophysics, Caltech, and the Carnegie Institution for Science.

Survey Design and Observations

Survey design was driven by plate availability from the United Kingdom Schmidt Telescope and the Palomar Observatory Sky Survey and by instrument capabilities at the Institute of Astronomy, Cambridge; survey footprints overlapped with programs by the Arecibo Observatory, the Very Large Array, and the Anglo-Australian Telescope. Observing strategy used photographic emulsions on glass plates taken with the UK Schmidt Telescope and the Palomar 48-inch Schmidt Telescope, coordinated with calibration fields referenced to standards from the Landolt photometric standard stars and astrometry tied to catalogues like the Tycho Catalogue, the Hipparcos Catalogue, and later to the International Celestial Reference Frame. Personnel with experience from projects at the Royal Observatory, Edinburgh, the Mount Stromlo Observatory, and the Australian National University contributed to scanning, while cross-identification used matches to the Infrared Astronomical Satellite and the ROSAT All-Sky Survey.

Data Reduction and Catalogues

Data reduction pipelines developed at the Institute of Astronomy, Cambridge used software tools comparable in aim to those created for the Sloan Digital Sky Survey and the Pan-STARRS project; catalogs produced parameters such as isophotal magnitudes, ellipticities, and positional centroids suitable for cross-correlation with the 2dF Galaxy Redshift Survey, the 6dF Galaxy Survey, and the Galaxy And Mass Assembly team efforts. Quality assessment referenced calibration techniques from the Landolt photometric standard stars, astrometric tying to the Tycho Catalogue, and systematic analyses influenced by methodologies from the Maximum Likelihood Estimation programs used by groups at the University of Cambridge and University of Edinburgh. The final catalogue enabled association with entries in the NASA/IPAC Extragalactic Database, the SIMBAD Astronomical Database, and archival holdings at the Royal Observatory, Edinburgh.

Scientific Results

The APM-derived catalogues supported measurements of the galaxy two-point correlation function and large-scale structure that were compared with results from the 2dF Galaxy Redshift Survey, the Sloan Digital Sky Survey, the Las Campanas Redshift Survey, and theoretical predictions from simulations at the Max Planck Institute for Astrophysics and the Institute for Advanced Study. Analyses using APM data informed determination of galaxy clustering bias applied in work by researchers affiliated with the University of Oxford, Princeton University, Harvard University, and Yale University, and contributed constraints on cosmological parameters that were later refined by teams behind the Wilkinson Microwave Anisotropy Probe and Planck (spacecraft). Studies of galaxy counts, morphology distributions, and photometric scaling relations used comparisons to datasets from the 2MASS Redshift Survey, the Hubble Space Telescope surveys, and observations by the European Southern Observatory.

Legacy and Impact

The APM catalogue influenced subsequent digital surveys and instrument projects including the Sloan Digital Sky Survey, the 2dF Galaxy Redshift Survey, the 6dF Galaxy Survey, and preparatory work for the Large Synoptic Survey Telescope now known as the Vera C. Rubin Observatory. Methodologies developed for plate digitization and morphological classification informed processing at institutions such as the Space Telescope Science Institute, the European Southern Observatory, and the National Optical Astronomy Observatory. The dataset provided historical baselines used by researchers at Cambridge University, University of Edinburgh, Australian National University, and the Anglo-Australian Observatory for studies later published in journals produced by the Royal Astronomical Society and presented at meetings of the International Astronomical Union.

Category:Astronomical surveys