 | |
| Alternative names | 2dF |
|---|---|
| Website | www |
 Related media on Commons | |
| Part of a series on |
| Physical cosmology |
|---|
 |
Early universe |
Components · Structure |
Inastronomy, the2dF Galaxy Redshift Survey (Two-degree-Field Galaxy Redshift Survey),2dF or2dFGRS is aredshift survey conducted by theAustralian Astronomical Observatory (AAO) with the 3.9mAnglo-Australian Telescope between 1997 and 11 April 2002.[1] The data from this survey were made public on 30 June 2003. The survey determined the large-scale structure in two large slices of the Universe to a depth of around 2.5 billion light years (redshift ~ 0.2). It was the world's largest redshift survey between 1998 (overtakingLas Campanas Redshift Survey) and 2003 (overtaken by theSloan Digital Sky Survey). Matthew Colless,Richard Ellis, Steve Maddox andJohn Peacock were in charge of the project. Team membersShaun Cole and John Peacock were awarded a share of the 2014Shaw Prize in astronomy for results from the 2dFGRS.
The 2dF survey covered an area of about 1500square degrees, surveying regions in both the north and the southgalactic poles.[2] The name derives from the fact that the survey instrument has a 2 degree diameter field of view.
The areas selected for observation were previously surveyed by the massiveAPM Galaxy Survey (on which Steve Maddox also worked).[2] The regions surveyed cover roughly 75 degrees ofright ascension for both bands, and thedeclination of the North Polar band was about 7.5 degrees while the declination of the South Polar band was about 15 degrees. Hundreds of isolated two degree fields near the South Polar band were also surveyed (seethis illustration, where black circles represent survey fields, and the red grid represents the earlier APM survey).
In total, thephotometry of 382,323 objects were measured, which includesspectra for 245,591 objects, of which 232,155 weregalaxies (221,414 with good quality spectra), 12,311 arestars, and 125 arequasi-stellar objects (quasars).[3] The survey necessitated 272 required nights of observation, spread over 5 years.
The survey was carried out with the 4 metreAnglo-Australian Telescope, with the2dF instrument installed at the primary focus permitting the observation of a field of 2 degrees per pointing. The instrument possesses aspectrograph equipped with two banks each of 200 optical fibres, permitting the simultaneous measurement of 400 spectra.
The limiting apparent magnitude of the survey is 19.5, covering objects with aredshift mostly within less than z=0.3 and a medianredshift of 0.11. The volume of the Universe covered by the survey is approximately 108h−1Mpc3, whereh corresponds to the value of theHubble constant,H0, divided by 100.H0 is approximately 70 km/s/Mpc. The largestredshift observed by the survey corresponds to a distance of 600h−1 Mpc.
The principal results obtained for the field ofcosmology by the 2dF survey are:
All these results are in agreement with the measurements of other experiments, notably those ofWMAP. They confirm thestandard cosmological model.
The 2dF survey also yields a unique view on our local cosmic environment. In the figure a 3-D reconstruction of the inner parts of the survey is shown, revealing a view on the cosmic structures in the nearby universe. Severalsuperclusters stand out, such as theSloan Great Wall, one of the largest structures[4] in the universe known to date (see alsoHuge-LQG).
| Photographic | |
|---|---|
| Infra-red | |
| Radio | |
| Spectroscopic |
|
