barak.virial.find_rvT¶

barak.virial.find_rvT(M, z, cosmo=None, mu=0.59)[source]¶

Find the virial radius, circular velocity and temperature for a dark matter halo at a given mass and redshift.

Parameters :	mass : array_like, shape N Total halo mass (including dark matter) in solar masses. z : array_like, shape M Redshift. cosmo : cosmology (optional) The cosmology to use. mu : float (optional) The mean molecular weight. The virial temperature is proportional to mu.
Returns :	vir : named tuple of ndarrays with shape (N, M) The virial radius (proper kpc), circular velocity (km/s) and temperature (K). If N or M is 1, that dimension is suppressed.

Notes

The value of mu depends on the ionization fraction of the gas; mu = 0.59 for a fully ionized primordial gas (the default), mu = 0.61 for a gas with ionized hydrogen but only singly ionized helium, and mu = 1.22 for neutral primordial gas.

Examples

>>> vir = find_rvT(1e12, 0)
>>> print vir.r, vir.v, vir.T
261.195728743 128.338776885 588643.476006
>>> r,v,T = find_rvT(1e12, [0.5, 1, 1.5, 2])
>>> r
array([ 198.57846074,  156.44358398,  127.91018732,  107.74327378])
>>> v
array([ 147.1888328 ,  165.82959995,  183.39536858,  199.82317152])
>>> T
array([  774259.0063081 ,   982789.81965216,  1202024.36495813,
       1427014.0148491 ])