光度距离[Luminosity Distance] - 达人(其实～我是卧底，来自外星)

2004/11/15 | 光度距离[Luminosity Distance]
类别(Ω〖物理〗) | 评论(0) | 阅读(68) | 发表于 13:21: Luminosity distance is a term used in astronomy to describe the distance at which an astronomical body would lie based on its observed luminosity in the absence of any unanticipated attenuation. The luminosity distance does however take into account the fact that the observed luminosity is attenuated by two factors, relativistic redshift and the Doppler shift of emission, each of which contributes a attenuation,
(1)

where z is the redshift. The observed flux is therefore given by
(2)

where is the proper distance and is the emitted luminosity. Solving for then gives
(3)

were a is the expansion parameter and r is the actual distance. Now define
(4)

giving the luminosity distance
(5); 0