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Below, we list the parameters that govern the bolometric luminosity of sources as well as their spectral energy distribution. These parameters are relevant to point sources (via the source_*
parameters), as well as populations of sources used in global 21-cm signal and/or meta-galactic radiation background calculations (simply replace source_
with pop_
).
source_type
Options:
star
: characterized by its temperature,source_temperature
, and ionizing photon luminosity,source_qdot
bh
: characterized by its mass,source_mass
etc.toy
: completely parameterized
source_temperature
If
source_type
isstar
, this is its surface temperature. [Kelvin]Default: 10^5 \ \text{K}
source_mass
If
source_type
isbh
, this is its mass [M_{\odot}]Default: 10 \ M_{\odot}
source_qdot
For toy radiation source, this is the ionizing photon luminosity. [\text{s}^{-1}]
Default: 5 \times 10^{48}\ \text{s}^{-1}
source_lifetime
Time after which radiation from this source will no longer be considered.
Default: 10^{10} [
time_units
]
We'll use I_E to denote to the SED of sources, which the user supplies via the parameter source_sed
or pop_sed
. It is proportional
to the energy emitted at energy E, NOT the number of photons
emitted at energy E, and is normalized (automatically by ARES) such that
\int_{\text{source_EminNorm}}^{\text{source_EminNorm}} \text{source_sed} dE = L_{\text{source_EminNorm}-\text{source_EminNorm}}
where the luminosity on the right-hand side is that determined by one of the parameters above (e.g., the Eddington luminosity of a source_mass
M_{\odot} BH) or for source populations via the pop_rad_yield
parameter. This auto-normalization guarantees the radiative yield of a single source (or source population) at some photon energy is equal to its bolometric luminosity times I_E.
We use square brackets on this page to denote the units of parameters.
source_sed
Options:
'bb'
: blackbody'pl'
: power-law'mcd'
; Multi-color disk (Mitsuda et al. 1984)'simpl'
: SIMPL Comptonization model (Steiner et al. 2009)'qso'
: Quasar template spectrum (Sazonov et al. 2004)
source_Emin
Minimum photon energy to consider in radiative transfer calculation.
Default: 200 [eV]
source_Emax
Maximum photon energy to consider in radiative transfer calculation.
Default: 3e4 [eV]
source_EminNorm
Minimum photon energy to consider in normalization.
Default: 200 [eV]
source_EmaxNorm
Maximum photon energy to consider in normalization.
Default: 3e4 [eV]
source_alpha
Power-law index of emission. Only used if
source_type
ispl
orsimpl
. Defined such that I_{\nu} \propto \nu^{\alpha}.Default: -1.5
Recall that I_{\nu} is proportional to the energy, not the number of photons, emitted at frequency \nu.
source_logN
Base-10 logarithm of the neutral absorbing column in units of \text{cm}^{-2}.
Default: -\infty
source_hardening
For non-zero absorbing columns, this parameter determines whether or not the column is applied before or after normalizing the source's luminosity.
Default:
extrinsic
source_Rmax
If
source_type
is 'mcd', this parameter sets the maximum size of the accretion disk being considered.Default: 1000 [gravitational radii, R_g = G M_{\bullet} / c^2, where M_{\bullet} is the black hole mass]