astropy_background¶
Calculate background cosmology using astropy
File |
background/astropy_background/astropy_background.py |
Attribution |
CosmoSIS Team (interface) |
Astropy Team (library) |
|
URL |
|
Citations |
The Astropy Collaboration et al 2022 ApJ 935 167 |
The astropy cosmology library can compute background evolution distances as a function of redshift for a range of different cosmologies:
FlatLambdaCDM
FlatwCDM
Flatw0waCDM
LambdaCDM
wCDM
w0waCDM
w0wzCDM
w0wzCDM
wpwaCDM
This module requires the user to choose one of these models and then will read the appropriate parameters for that model and compute a range of distance measures.
Assumptions¶
Various depending on model choice
Setup Parameters¶
Name |
Type |
Default |
Description |
|---|---|---|---|
zmax |
real |
Maximum redshift to compute distances to |
|
nz |
real |
Number of redshift sample points to compute distances to |
|
model |
str |
Name of the astropy model to use |
Input values¶
Section |
Name |
Type |
Default |
Description |
|---|---|---|---|---|
cosmological_parameters |
hubble |
real |
Hubble parameter today in km/s/Mpc |
|
omega_m |
real |
Dark matter density fraction today |
||
omega_lambda |
real |
Dark energy density fraction today. Only for some models. |
||
w |
real |
Dark energy equation of state today. Only for some models. |
||
wa |
real |
Dark energy equation of state scale factor derivative. Only for some models. |
||
wz |
real |
Dark energy equation of state redshift derivative today. Only for some models. |
||
zp |
real |
Redshift pivot for wpwaCDM model |
||
wp |
real |
Dark energy equation of state at zp for wpwaCDM model |
Output values¶
Section |
Name |
Type |
Description |
|---|---|---|---|
distances |
z |
real 1d |
Redshifts of distance samples |
a |
real 1d |
Scale factor of distance samples |
|
d_a |
real 1d |
Angular diameter distance in Mpc |
|
d_m |
real 1d |
Co-moving transverse distance in Mpc |
|
d_l |
real 1d |
Luminosity distance in Mpc |
|
mu |
real 1d |
Distance modulus |
|
h |
real 1d |
Hubble parameter with in units of Mpc |
|
d_v |
real 1d |
Comoving volume in Mpc^3 |
|
d_c |
real 1d |
Comoving line-of-sight distance in Mpc |