cosmocalc
¶
Calculate useful values for a given cosmology. This module uses code adapted from CC.py (James Schombert) which is a Python version of the Cosmology Calculator (Ned Wright).
The following values are calculated:
Name Value Units z Input redshift H0 Hubble constant WR Omega(radiation) WK Omega curvaturve = 1-Omega(total) WM Omega matter WV Omega vacuum DTT Time from z to now Gyr age Age of Universe Gyr zage Age of Universe at redshift z Gyr DCMR Comoving radial distance Gyr Mpc cm VCM Comoving volume within redshift Gpc3 DA Angular size distance Gyr Mpc cm DL Luminosity distance Gyr Mpc cm PS Plate scale - distance per arcsec kpc cm
Copyright: | Smithsonian Astrophysical Observatory (2009) |
---|---|
Author: | Tom Aldcroft (aldcroft@head.cfa.harvard.edu) |
Functions¶
-
cosmocalc.
cosmocalc
(z, H0=71, WM=0.27, WV=None)¶ Calculate useful values for the supplied cosmology.
This routine returns a dictionary of values in the form
<name>: <value>
, where the values are supplied in “natural” units for cosmology, e.g. 1/H0. In addition various useful unit conversions are done and stored in the dictionary as<name>_<unit>: <value>
. E.g. angular size distance:'DA': 0.38250549415474988, 'DA_Gyr': 5.2678010166833023, 'DA_Mpc': 1615.1022857909447, 'DA_cm': 4.9836849147807571e+27
Example:
>>> from cosmocalc import cosmocalc >>> from pprint import pprint >>> pprint(cosmocalc(3, H0=75, WM=.25)) {'DA': 0.39103776375786625, 'DA_Gyr': 5.0980896720325548, 'DA_Mpc': 1563.0689649039205, 'DA_cm': 4.8231268630387788e+27, 'DCMR': 1.564151055031465, 'DCMR_Gyr': 20.392358688130219, 'DCMR_Mpc': 6252.2758596156818, 'DCMR_cm': 1.9292507452155115e+28, 'DL': 6.25660422012586, 'DL_Gyr': 81.569434752520877, 'DL_Mpc': 25009.103438462727, 'DL_cm': 7.717002980862046e+28, 'DTT': 0.84826379084317027, 'DTT_Gyr': 11.059097795819358, 'H0': 75, 'PS_cm': 2.3383178917293232e+22, 'PS_kpc': 7.5779721961095019, 'VCM': 1.2756009121294902, 'VCM_Gpc3': 1023.7714254161302, 'WK': 0.0, 'WM': 0.25, 'WR': 7.4044444444444448e-05, 'WV': 0.74992595555555552, 'age': 1.0133755371756261, 'age_Gyr': 13.211714670004362, 'z': 3, 'zage': 0.16511174633245579, 'zage_Gyr': 2.1526168741850036}
Parameters: - z – redshift
- H0 – Hubble constant (default = 71)
- WM – Omega matter (default = 0.27)
- WV – Omega vacuum (default = 1.0 - WM - 0.4165/(H0*H0))
Return type: dictionary of cosmology values (name_unit = value)
-
cosmocalc.
get_options
()¶ cosmocalc.py [options] redshift [name_unit [name_unit2 …]]
Allowed
name_unit
values:DA DA_Gyr DA_Mpc DA_cm DL DL_Gyr DL_Mpc DL_cm DCMR DCMR_Gyr DCMR_Mpc DCMR_cm PS_kpc PS_cm DTT DTT_Gyr VCM VCM_Gpc3 age age_Gyr zage zage_Gyr H0 WM WV WK WR z
If no
name_unit
values are supplied then all the above will be printed.
-
cosmocalc.
main
()¶