WiggleZ

WiggleZ was a large-scale spectroscopic redshift survey of star-forming galaxies conducted in the late 2000s to map baryon acoustic oscillation features and probe dark energy and large-scale structure. It targeted ultraviolet-selected emission-line galaxies across several high-latitude survey fields using the Anglo-Australian Telescope and the AAOmega spectrograph, producing one of the first robust detections of baryon acoustic oscillations at intermediate redshift. The project involved collaborations among Australian and international institutions including the Anglo-Australian Observatory, Australian National University, University of Oxford, and teams linked to surveys such as Sloan Digital Sky Survey and Galaxy Evolution Explorer.

Overview

The survey aimed to measure the cosmic expansion history by detecting the imprint of acoustic oscillations from the Early universe—specifically the baryon acoustic oscillation feature first predicted in the context of Cosmic microwave background physics and observed in surveys like 2dF Galaxy Redshift Survey and Sloan Digital Sky Survey. WiggleZ selected bright, blue emission-line galaxies out to redshift z~1 to maximize volume and tracer density comparable to contemporaneous programs such as Baryon Oscillation Spectroscopic Survey and deep field campaigns like COSMOS. Project coordination involved observing strategies and analysis pipelines developed with experience from 2dFGRS teams and instrumentation groups at the Anglo-Australian Observatory.

Survey design and instrumentation

The target selection combined ultraviolet photometry from Galaxy Evolution Explorer with optical imaging from surveys including Two Micron All Sky Survey and wide-area optical catalogs to identify ultraviolet-luminous, star-forming galaxies similar to emitters found in studies like DEEP2 Redshift Survey. Observations used the Anglo-Australian Telescope with the AAOmega spectrograph fed by the 2dF fibre positioner to obtain multi-object spectroscopy over degree-scale fields, following instrumental precedents set by instruments used in programs such as 6dF Galaxy Survey and 2dF Galaxy Redshift Survey. The survey footprint comprised several well-studied fields overlapping with legacy datasets from Sloan Digital Sky Survey, CFHT Legacy Survey, and other imaging projects to enable cross-correlation analyses with catalogs like GALEX and photometric catalogs tied to Pan-STARRS-era works.

Observations and data processing

WiggleZ conducted observations across multiple semesters between 2006 and 2011, accumulating spectra for hundreds of thousands of targets. The observing program scheduled runs at the Siding Spring Observatory site using fiber allocation strategies informed by designs used in BOSS and 2dF campaigns. Data reduction used pipelines for spectral extraction, wavelength calibration, sky subtraction, and redshift assignment comparable to those developed for AAOmega programs, with quality flags and visual inspection steps similar to those used in DEEP2 and VVDS. Catalog construction incorporated cross-matching with photometric datasets from GALEX, SDSS, and near-infrared surveys to assemble target properties for clustering analysis and to produce catalogs of emission-line galaxies with measured line fluxes, continuum properties, and redshifts.

Scientific results

WiggleZ produced multiple high-impact results including a detection of the baryon acoustic oscillation peak at z~0.6, providing constraints on the distance-redshift relation that complemented measurements from Type Ia supernovae campaigns and the Cosmic microwave background results from Wilkinson Microwave Anisotropy Probe and later Planck. The survey measured the growth rate of structure via redshift-space distortions, constraining models of General relativity and alternative gravity scenarios tested alongside results from DES and CFHTLenS. WiggleZ clustering analyses informed determinations of the matter power spectrum and parameters such as the matter density parameter often compared with constraints from WMAP and large-scale probes including 2dFGRS and BOSS. The emission-line galaxy sample enabled studies of star formation rates, metallicities, and the relationship between environment and galaxy properties, relating results to findings from DEEP2, zCOSMOS, and VVDS.

Legacy and data releases

The WiggleZ collaboration released public data products including redshift catalogs, spectra, and clustering measurements that have been used by researchers working on cosmological parameter estimation, galaxy evolution, and cross-correlations with surveys such as Planck, WISE, and Herschel Space Observatory. Its methodologies influenced successor surveys of emission-line galaxies in projects like eBOSS and planning for future programs with facilities such as Dark Energy Spectroscopic Instrument and the European Southern Observatory-led initiatives. Legacy outputs include value-added catalogs and clustering templates that continue to be cited alongside datasets from SDSS, 2dF, BOSS, and imaging programs like CFHTLS and Pan-STARRS1.

Category:Redshift surveys Category:Observational cosmology