Overview

redshift

Return to overview »

You are looking at 1-20 of 111 entries

View:

Abell cluster

Abell cluster  

A cluster of galaxies listed in the Abell Catalogue. To appear in the catalogue, a cluster must satisfy selection criteria which include containing more than 50 galaxies and having a dense ...
acoustic peaks

acoustic peaks  

The term ‘acoustic peaks’ refers to char-acteristic features seen in the structure of inhomogeneities in the Universe. In the young Universe, before the epoch of decoupling when the cosmic microwave ...
active galaxy

active galaxy  

A galaxy that contains an active galactic nucleus (AGN), i.e. a central region that gives off a great deal of electromagnetic radiation. This emission is thought to be due to the accretion of matter ...
age of the Universe

age of the Universe  

A time determined by the reciprocal of the value of the Hubble constant to be about 13.7 billion years. The calculation of the Hubble constant, and hence the age of the universe, depends on which ...
ALMA

ALMA  

(Atacama Large Millimetre Array)ALMA, the Atacama Large Millimetre Array, is an international project to build a large array of antennae that will study the Universe in unprecedented detail in ...
alternative cosmologies

alternative cosmologies  

Most cosmologists today believe in the hot big bang cosmology (HBBC; see ‘Overview’), in which the Universe began as an infinitely hot and dense initial singularity which subsequently expanded and ...
angular-diameter distance

angular-diameter distance  

The angular-diameter distance is a way of expressing the distance to a cosmological object. It is not the true distance, but rather the distance that the object appears to have ...
APM galaxy survey

APM galaxy survey  

The Automated Plate Measurement (APM) Galaxy Survey was one of two surveys (the other being the Edinburgh–Durham Southern Galaxy Catalogue) carried out in the late 1980s and early 1990s which ...
big Bang

big Bang  

The hypothetical but widely accepted ‘explosive’ event that marked the origin of the universe as we know it. At the time of the Big Bang, the entire universe was squeezed into an infinitely small, ...
black-body spectrum

black-body spectrum  

A black-body is a perfect absorber and emitter of radiation. When placed in a bath of radiation, a black-body alters its temperature until an equilibrium is reached between the radiation ...
blueshift

blueshift  

A Doppler shift of light towards the blue end of the spectrum, caused when the emitting source is approaching the observer. See also Radial Velocity; Redshift.
bulk motions

bulk motions  

As well as moving apart from each other as the Universe expands, galaxies have peculiar velocities relative to this Hubble expansion. If there is a large overdensity in a particular ...
CfA Redshift Survey

CfA Redshift Survey  

The Center for Astrophysics (CfA) Redshift Survey was started in 1977 and the first part was completed in 1982. It contained redshifts for 2 401 galaxies brighter than magnitude 14.5 ...
cluster of galaxies

cluster of galaxies  

An aggregation of galaxies, which may or may not be bound together by gravity. For example, our Galaxy, the Milky Way, is a member of the Local Group, a rather small cluster of which the only other ...
cone plot

cone plot  

Also known as a wedge plot, this is a way of illustrating the distribution of sources in a redshift survey. Using polar coordinates (r, θ), with r being distance from ...
correlation function

correlation function  

A mathematical function used in the statistical description of galaxy clustering. It measures the excess probability of finding a galaxy at a given distance from a particular galaxy, compared with ...
cosmic infrared background

cosmic infrared background  

(CIRB)The cosmic infrared background refers to all diffuse infrared radiation external to the Milky Way. It arises from the cumulative radiation from stars and galaxies dating back to the ...
cosmic microwave background

cosmic microwave background  

A faint, diffuse glow coming from all directions in the sky, most intense at a wavelength of around 1 mm; also known as the microwave background radiation or cosmic background radiation. Its ...
cosmic structure

cosmic structure  

Cosmic structure, also known as the large-scale structure of the Universe, describes the way that galaxies and other tracers of mass in the Universe are distributed. Although on the largest ...
cosmic web

cosmic web  

The cosmic web is the name given to the filamentary, or web-like, distribution of matter in the Universe. It is apparent both in redshift surveys of the galaxy distribution (See ...

View: