Calculating Radii Module¶
This module contains codes for calculating radii R200, R500, etc (and corresponding masses) of halos.
Based on Douglas Rennehan’s code on HaloAnalysis.
- XIGrM.calculate_R.get_radius(halo, overdensities=array([], dtype=float64), rho_crit=None, precision=0.01, rmax=None, cen=array([], dtype=float64), prop=None)[source]¶
Calculate different radii of a given halo with a decreasing sphere method.
- Parameters
- halo
Halo to be calculated, SimSnap in pynbody. Paramaters need to be in physical_units.
- overdensity
Overdensity factor $Delta$s. Must be a list!
- rho_crit
Critical density of the universe at the redshift of current SimSnap. Must be in units of Msol/kpc**3.
- precision
Precision for calculating radius.
- rmax
The radius at which start using decreasing sphere method. If 0, then use 2 * distance of farthest particle. If set, must be in units of kpc or convertible to kpc via pynbody.
- cen
center coordinates of calculated halo. If not provided, then will load from property dictionary or calculate via pynbody.analysis.halo.center().
- prop
halo.properties dictionary. If set to 0 then will automatically load it. Only used for getting boxsize and redshift.
- Returns
- mass
Dict of masses of the halo within calculated radii.
- radius
Dict of radii of the halo at given overdensities.
- XIGrM.calculate_R.get_radius_bisection(halo, overdensities=array([], dtype=float64), rho_crit=0, precision=0.01, prop=0)[source]¶
Calculate different radii of a given halo with a bisection method. This is a prototype without much optimization. And you will need to modify the source code to make it compatible with the module.
- Parameters
- halo
- Halo to be calculated, SimSnap in pynbody.
Paramaters need to be in physical_units.
- overdensity
Overdensity factor $Delta$s.
- rho_crit
Critical density of the universe at the redshift of current SimSnap. Must be in units of halo[‘mass’].units / halo[‘pos’].units**3.
- precision
Precision within which radii is calculated.
- Returns
- mass
Dict of masses of the halo within calculated radii.
- radius
Dict of radii of the halo at given overdensities.