2dFGRS

2dFGRS
Willem Schaap · CC BY-SA 3.0 · source
Name	2dF Galaxy Redshift Survey
Start date	1997
Completed	2002
Principal investigators	Matthew Colless, John Peacock, Warrick Couch
Observatory	Anglo-Australian Observatory
Telescope	Anglo-Australian Telescope
Instrument	Two-degree Field
Data products	galaxy redshifts, spectra, luminosity functions

2dFGRS was a large astronomical redshift survey that mapped the three-dimensional distribution of galaxies over wide areas of the southern sky. It used the Anglo-Australian Telescope and the Two-degree Field instrument to measure redshifts for hundreds of thousands of galaxies, enabling studies that connected observational programs such as Sloan Digital Sky Survey comparisons, tests inspired by predictions from Cold Dark Matter simulations, and analyses related to results from Cosmic Microwave Background experiments like WMAP and COBE. The survey catalyzed collaborations among institutions including the Anglo-Australian Observatory, the University of Cambridge, and the University of Oxford.

Overview

The survey targeted galaxies selected primarily from the ESO and APM Galaxy Survey catalogs and complemented by imaging from facilities such as the UK Schmidt Telescope and the Sloan Digital Sky Survey commissioning data; teams led by Matthew Colless, John Peacock, and Warrick Couch designed the project to probe scales relevant to analyses by Peebles and tests of clustering predicted in simulations by groups including those around Simon White and Carlos Frenk. The 2dF instrument on the Anglo-Australian Telescope allowed multiplexed spectroscopy, enabling redshift measurements that informed parameter estimation efforts comparable to work by Max Tegmark, Scott Dodelson, and Marc Davis and provided data of interest to researchers studying implications for Lambda-CDM and alternatives considered by Joel Primack.

Survey Design and Instrumentation

Survey geometry comprised two declination strips and random fields to sample cosmic variance, with selection functions designed to match photometric catalogs produced with input from the Automated Plate Measuring Facility and catalogs cross-referenced to work by Gordon Efstathiou and John Huchra. The Two-degree Field instrument utilized fiber positioning hardware developed through engineering efforts associated with projects at the Anglo-Australian Observatory and drew on experience from multi-object spectrographs used at the W. M. Keck Observatory and the Very Large Telescope. Instrument characteristics such as fiber diameter and spectral resolution were specified to meet redshift precision goals comparable to requirements in analyses by Nick Kaiser and Adrian Jenkins. Organizational management involved collaborations among the University of Melbourne, University of Edinburgh, Carnegie Institution for Science, and other institutions.

Observations and Data Reduction

Observing campaigns were scheduled at the Siding Spring Observatory using queue strategies informed by practices from observatories like Mauna Kea facilities; nightly calibrations used lamps and sky exposures similar to those developed at the Isaac Newton Group of Telescopes. Raw spectra underwent reduction pipelines developed by teams including personnel associated with Anglo-Australian Observatory software groups; algorithms borrowed concepts from work by John Huchra, Marc Davis, and Antony Lewis for redshift estimation, spectral classification, and error characterization. Data quality assessments referenced standards established in spectroscopic surveys by collaborators at Australian National University, University of Durham, and University of Cambridge and used statistical methods aligned with approaches from Geraint Lewis and Ofer Lahav.

Scientific Results and Discoveries

Key results included precise measurements of the galaxy power spectrum and two-point correlation function, informing constraints on parameters discussed in analyses by Martin Rees, Simon White, Carlos Frenk, George Efstathiou, and John Peacock. The survey measured the baryon acoustic feature consistent with predictions from Peebles and results from WMAP and enabled estimates of the matter density parameter and bias factors that complemented work by Max Tegmark, Hector de Vega, and Andrew Liddle. Studies using 2dFGRS spectra advanced understanding of galaxy luminosity functions building on methods from Schechter and subsequent empirical work by Stephen Maddox and Will Percival. Environmental dependence of galaxy properties tied into analyses by Alan Dressler and morphological studies informed by comparisons with samples compiled by Graham A. Smith and teams at the Hubble Space Telescope. Redshift-space distortion measurements provided constraints on growth rate consistent with theoretical frameworks developed by Nick Kaiser and tested models proposed by Edvard Mörtsell and others. Cross-correlation analyses linked the survey to cluster catalogs studied by Gioia and Abell compilations, and comparisons with supernova cosmology data from groups like those led by Brian Schmidt and Saul Perlmutter helped triangulate cosmological parameters.

Data Release and Access

The collaboration released catalog products and spectra through data releases modeled after community practices set by the Sloan Digital Sky Survey and archives at the Centre de Données astronomiques de Strasbourg; institutional partners included the Anglo-Australian Observatory, the Australian Astronomical Observatory, and university data centers at University of Cambridge and University of Oxford. Access provisions allowed researchers from institutions such as Australian National University, University of Melbourne, Imperial College London, and University of Chicago to use the catalogs for follow-up studies, while external projects including those at the Max Planck Institute for Astrophysics and Princeton University performed independent analyses.

Legacy and Impact on Cosmology

2dFGRS influenced successor surveys and instruments including the Sloan Digital Sky Survey, WiggleZ Dark Energy Survey, and design choices for facilities like the Dark Energy Spectroscopic Instrument and the Large Synoptic Survey Telescope. Its measurements informed parameter estimation efforts by teams analyzing Cosmic Microwave Background data from WMAP and Planck and guided theoretical model building in Lambda-CDM and alternatives pursued by researchers at Cambridge University and Stanford University. The survey's datasets continue to be used in studies led by groups at the Institute of Astronomy, Cambridge, California Institute of Technology, and University of California, Berkeley for projects including galaxy formation modeling by Carlos Frenk's collaborators and large-scale structure analyses by Jo Short and others, cementing its role in the empirical foundation of modern observational cosmology.

Category:Astronomical surveys