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• Redshift_survey abstract "In astronomy, a redshift survey is a survey of a section of the sky to measure the redshift of astronomical objects: usually galaxies, but sometimes other objects such as galaxy clusters or quasars. Using Hubble's law, the redshift can be used to estimate the distance of an object from Earth. By combining redshift with angular position data, a redshift survey maps the 3D distribution of matter within a field of the sky. These observations are used to measure detailed statistical properties of the large-scale structure of the universe. In conjunction with observations of early structure in the cosmic microwave background, these results can place strong constraints on cosmological parameters such as the average matter density and the Hubble constant.Generally the construction of a redshift survey involves two phases: first the selected area of the sky is imaged with a wide-field telescope, then galaxies brighter than a defined limit are selected from the resulting images as non-pointlike objects; optionally, colour selection may also be used to assist discrimination between stars and galaxies. Secondly, the selected galaxies are observed by spectroscopy, most commonly at visible wavelengths, to measure the wavelengths of prominent spectral lines; comparing observed and laboratory wavelengths then gives the redshift for each galaxy.The Great Wall, a vast conglomeration of galaxies over 500 million light-years wide, provides a dramatic example of a large-scale structure that redshift surveys can detect.The first systematic redshift survey was the CfA Redshift Survey of around 2,200 galaxies, started in 1977 with the initial data collection completed in 1982. This was later extended to the CfA2 redshift survey of 15,000 galaxies, completed in the early 1990s.These early redshift surveys were limited in size by taking a spectrum for one galaxy at a time; from the 1990s, the development of fibre-optic spectrographs and multi-slit spectrographs enabled spectra for several hundred galaxies to be observed simultaneously, and much larger redshift surveys became feasible. Notable examples are the 2dF Galaxy Redshift Survey (221,000 redshifts, completed 2002); the Sloan Digital Sky Survey (approximately 1 million redshifts by 2007) and the Galaxy And Mass Assembly survey. At high redshift the largest current surveys are the DEEP2 Redshift Survey and the VIMOS-VLT Deep Survey (VVDS); these have around 50,000 redshifts each, and are mainly focused on galaxy evolution.Because of the demands on observing time required to obtain spectroscopic redshifts (i.e., redshifts determined directly from spectral features measured at high precision), a common alternative is to use photometric redshifts based on model fits to the brightnesses and colors of objects. Such "photo-z's" can be used in large surveys to estimate the spatial distribution of galaxies and quasars, provided the galaxy types and colors are well understood in a particular redshift range. At present, the errors on photometric redshift measurements are significantly higher than those of spectroscopic redshifts, but future surveys (for example, the LSST) aim to significantly refine the technique.".
• Redshift_survey thumbnail 2dfgrs.png?width=300.
• Redshift_survey wikiPageExternalLink probes-lss.html.
• Redshift_survey wikiPageExternalLink galaxy-redshift-surveys.html.
• Redshift_survey wikiPageID "1157197".
• Redshift_survey wikiPageLength "8563".
• Redshift_survey wikiPageOutDegree "31".
• Redshift_survey wikiPageRevisionID "676615909".
• Redshift_survey wikiPageWikiLink 2dF_Galaxy_Redshift_Survey.
• Redshift_survey wikiPageWikiLink Astronomical_object.
• Redshift_survey wikiPageWikiLink Astronomical_spectroscopy.
• Redshift_survey wikiPageWikiLink Astronomical_survey.
• Redshift_survey wikiPageWikiLink Astronomical_surveys.
• Redshift_survey wikiPageWikiLink Astronomy.
• Redshift_survey wikiPageWikiLink Baryon_acoustic_oscillations.
• Redshift_survey wikiPageWikiLink Category:Large-scale_structure_of_the_cosmos.
• Redshift_survey wikiPageWikiLink Category:Observational_astronomy.
• Redshift_survey wikiPageWikiLink Category:Physical_cosmology.
• Redshift_survey wikiPageWikiLink CfA2_Great_Wall.
• Redshift_survey wikiPageWikiLink CfA_Redshift_Survey.
• Redshift_survey wikiPageWikiLink Cosmic_microwave_background.
• Redshift_survey wikiPageWikiLink DEEP2_Redshift_Survey.
• Redshift_survey wikiPageWikiLink Galaxy.
• Redshift_survey wikiPageWikiLink Galaxy_And_Mass_Assembly_survey.
• Redshift_survey wikiPageWikiLink Galaxy_color-magnitude_diagram.
• Redshift_survey wikiPageWikiLink Galaxy_color–magnitude_diagram.
• Redshift_survey wikiPageWikiLink Great_Wall_(astronomy).
• Redshift_survey wikiPageWikiLink Hubbles_law.
• Redshift_survey wikiPageWikiLink Intensity_mapping.
• Redshift_survey wikiPageWikiLink Large-scale_structure_of_the_cosmos.
• Redshift_survey wikiPageWikiLink Large_Synoptic_Survey_Telescope.
• Redshift_survey wikiPageWikiLink Observable_universe.
• Redshift_survey wikiPageWikiLink Photometric_redshift.
• Redshift_survey wikiPageWikiLink Redshift.
• Redshift_survey wikiPageWikiLink Redshift-space_distortions.
• Redshift_survey wikiPageWikiLink Sloan_Digital_Sky_Survey.
• Redshift_survey wikiPageWikiLink Spectral_line.
• Redshift_survey wikiPageWikiLink Spectroscopic_astronomy.
• Redshift_survey wikiPageWikiLink Spectroscopy.
• Redshift_survey wikiPageWikiLink VIMOS-VLT_Deep_Survey.
• Redshift_survey wikiPageWikiLink VIMOS-VLT_Deep_Survey_(VVDS).
• Redshift_survey wikiPageWikiLink File:2dfgrs.png.
• Redshift_survey wikiPageWikiLinkText "Redshift Survey".
• Redshift_survey wikiPageWikiLinkText "Redshift survey".
• Redshift_survey wikiPageWikiLinkText "Sky surveys".
• Redshift_survey wikiPageWikiLinkText "galaxy redshift survey".
• Redshift_survey wikiPageWikiLinkText "galaxy redshift surveys".
• Redshift_survey wikiPageWikiLinkText "galaxy surveys".
• Redshift_survey wikiPageWikiLinkText "redshift survey".
• Redshift_survey hasPhotoCollection Redshift_survey.
• Redshift_survey wikiPageUsesTemplate Template:Reflist.
• Redshift_survey subject Category:Large-scale_structure_of_the_cosmos.
• Redshift_survey subject Category:Observational_astronomy.
• Redshift_survey subject Category:Physical_cosmology.
• Redshift_survey hypernym Survey.
• Redshift_survey type Article.
• Redshift_survey type Organisation.
• Redshift_survey type Article.
• Redshift_survey type Physic.
• Redshift_survey type Sub-discipline.
• Redshift_survey comment "In astronomy, a redshift survey is a survey of a section of the sky to measure the redshift of astronomical objects: usually galaxies, but sometimes other objects such as galaxy clusters or quasars. Using Hubble's law, the redshift can be used to estimate the distance of an object from Earth. By combining redshift with angular position data, a redshift survey maps the 3D distribution of matter within a field of the sky.".
• Redshift_survey label "Redshift survey".
• Redshift_survey sameAs نقشه‌برداری_انتقال_به_سرخ.
• Redshift_survey sameAs Rilevamento_degli_spostamenti_verso_il_rosso.
• Redshift_survey sameAs m.04c193.
• Redshift_survey sameAs Q3935817.
• Redshift_survey sameAs Q3935817.
• Redshift_survey sameAs 紅移巡天.
• Redshift_survey wasDerivedFrom Redshift_survey?oldid=676615909.
• Redshift_survey depiction 2dfgrs.png.
• Redshift_survey isPrimaryTopicOf Redshift_survey.