I am trying to calculate the redshift drift where its written as
$$\frac{dz}{dt} = (1+z)H_0 - H \tag{1}$$
We also know that $$1+z = a(t_o) / a(t_e) \tag{2}$$
and $$H_0 = \frac{\dot{a}(t_0)}{a(t_0)}$$
$$H = \frac{\dot{a}(t_e)}{a(t_e)}$$
Asked
Active
Viewed 126 times
0
-
Related question: https://physics.stackexchange.com/q/400386/ – D. Halsey Sep 30 '20 at 12:45
-
Layla, can you specify your problem? If you know the scale factors then the redshift is given by your equation (2). – psm Sep 30 '20 at 15:13
-
@psm What information do you need ? – seVenVo1d Oct 03 '20 at 18:29
1 Answers
0
You have an inaccuracy in the first equation regarding "H". Normally in the context of differentiating with respect to t, functions are assumed to be having a function of t as an argument, and if none is given, then it is normally assumed that H=H(t). In the case of your equation, H=H(z)=H(z(t)). See
What is the cosmological redshift drift effect? .
I suggest the other equations should also be in terms of z rather than t. You should also note that z(t0)=0, and z(t)=(1/a(t))-1.
I hope this helps.
Buzz
- 354
- 2
- 11