Problem Types¶
There are several pre-defined problem types one can access via the parameter
ptype
. Note that you can also grab the parameters for a given problem type using the Parameter Bundles machinery. For example,
import ares
pars = ares.util.ParameterBundle('prob:101')
will return a dictionary of parameters for problem_type=101
.
ptype
\(\leq 20\)¶
These are all 1-D radiative transfer problems. Will document eventually!
ptype
\(\geq 100\)¶
These are all uniform background / reionization / global 21-cm problems.
100¶
Blank slate global 21-cm signal problem – no default populations will be initialized, and all “control parameters” take on their default values. Basically this means that the simplest solvers / assumptions will be adopted for everything. Only use this if you know what you’re doing!
101¶
Simple global 21-cm signal problem in which the Ly-\(\alpha\), LyC, and X-ray production is proportional to the rate of collapse onto all halos exceeding a minimum virial temperature threshold (pop_Tmin
) or mass (pop_Mmin
). The main free parameters are:
pop_yield{0}
: Number of LW photons emitted per baryon of star formation. Stellar spectrum assumed flat.pop_yield{1}
: Normalization of the X-ray luminosity star-formation rate relation in the 0.5-8 keV band.pop_yield{2}
: Number of LyC photons emitted per baryon of star formation.pop_fesc{2}
: Escape fraction of LyC radiation.pop_Tmin{0}
: Minimum virial temperature of star-forming halos. Note thatpop_Tmin{1}
andpop_Tmin{2}
are automatically linked topop_Tmin{0}
.Note
In earlier versions of ares these parameters were denoted more simply as
Nlw
,fX
,Nion
,fesc
, andTmin
. You can still use this approach (i.e., this shouldn’t break backward compatibility), though in the future this may not be true.
102¶
Slightly more advanced global 21-cm signal problem in which the Ly-\(\alpha\), LyC, and X-ray production is still proportional to the rate of collapse onto all halos exceeding a minimum virial temperature threshold (pop_Tmin
) or mass (pop_Mmin
), but the photon production efficiencies are calculated from a stellar synthesis model. The main difference between this problem and problem 101 is that the LW and LyC efficiencies are no longer independent. As a result, there are only two source populations: one stellar and one for X-rays. The main parameters are slightly different as a result:
pop_sed{0}
: Spectral energy distribution of stellar populations. By default, this iseldridge2009
, i.e., the BPASS version 1.0 models.pop_Z{0}
: Stellar metallicity.pop_fesc{0}
: Escape fraction of LyC radiation.pop_yield{1}
: Normalization of the X-ray luminosity star-formation rate relation in the 0.5-8 keV band.pop_Tmin{0}
: Minimum virial temperature of star-forming halos. Note thatpop_Tmin{1}
is automatically linked topop_Tmin{0}
.