... Under certain conditions, like those in the nucleus of a QSO, all atoms can be made to emit light at particular wavelengths. ... If that source is approaching the observer, the wave is squashed up onto itself making the wavelength shorter. ... This is redshift. ... You can see how the section of the QSO spectrum which we observe changes with redshift. ... We then see how far we had to slide the observed spectrum along the scale to make it match and that is the objects redshift. ... The 2QZ team . ...

... Synchronous Evolution of Galaxies in Groups: NGC 524 Group O. K. Sil'chenko and V. L. Afanasiev 245 ISSN 1990-3413, Astrophysical Bulletin, 2012, Vol. ... Four of the five galaxies revealed synchronized bursts of star formation in the nuclei 1­2 Gyr ago. The only galaxy, in which the ages of stellar population in the nucleus and in the bulge coincide (i.e. the nuclear burst of star formation did not take place) is NGC 502, the farthest from the center of the group of all the galaxies studied. ...