Physics Parameters¶
radiative_transfer
No astrophysical sources.
Includes ionization/heating from astrophysical sources.
Default: 1
compton_scattering
OFF
Include Compton scattering between free electrons and CMB.
Default: 1
secondary_ionization
Determine what fraction of photo-electron energy gets deposited in various channels, such as heat, ionization, and excitation.
All photo-electron energy deposited as heat.
Compute using fits of Shull & vanSteenberg (1985).
Compute using energy-dependent fits of Ricotti, Gnedin, & Shull (2002).
Compute using look-up tables of Furlanetto & Stoever (2010).
Default: 1
fXh
Set fractional heating by photo-electrons by-hand. Currently must be a constant. Will override choice of
secondary_ionization
if supplied.Default:
None
clumping_factor
Multiplicative enhancement to the recombination rate.
Default: 1
approx_He
See following table for possible behaviors depending on value of
include_He
.Default: False
|
|
description |
---|---|---|
False |
False |
Neglects helium entirely |
True |
True |
Set \(x_{\text{HeII}} = x_{\text{HII}}\), and set \(x_{\text{HeIII}} = 0\) |
True |
False |
Solve for helium self-consistently |
approx_sigma
Compute bound-free absorption cross sections via fits of Verner et al. (1996).
Approximate cross-sections as \(\sigma \propto \nu^{-3}\)
Default: 0
approx_lwb
Solves RTE (i.e., full “sawtooth” background).
Assume flat spectrum between Lyman-\(\alpha\) and the Lyman limit.
Default: 1
approx_xrb
Solves RTE.
Heating due to instantaneous X-ray luminosity.
Default: 1
discrete_lwb
Performs integrals numerically using continuous functions for integrands (very slow)
Integrates transfer equation over discrete set of points.
Default: 1
discrete_xrb
Performs integrals numerically using continuous functions for integrands (very slow)
Integrates transfer equation over discrete set of points.
Default: 1
approx_Salpha
Not implemented
Assume \(S_{\alpha} = 1\)
Use formulae of Chuzhoy, Alvarez, & Shapiro (2005).
Use formulae of Furlanetto & Pritchard (2006)
Default: 1
lya_nmax
Default: 23
lya_injected
Include photons injected at line-center?
Default:
True
lya_continuum
Include photons redshifting into the blue-wing of the Lyman-\(\alpha\) line?
Default:
True
recombination
Which recombination method to use? Can be
"A"
,"B"
, or0
, the first two options being standard case-A or case-B recombination, whereas the last option artificially turns off recombinations (useful for analytic tests).Default:
B