"""Model of the SED from type Ia (thermonuclear) supernovae."""
from typing import ClassVar
from astropy import units as u
from uvex_transients.models.arnett import ArnettDecaySED
from uvex_transients.models.core.parameters import Parameter
from uvex_transients.models.core.priors import (
ConstantPrior,
NormalPrior,
TruncatedNormalPrior,
UniformPrior,
)
__all__ = ["TypeIaSED"]
[docs]
class TypeIaSED(ArnettDecaySED):
r"""
Type Ia supernova SED, with priors fit to a ZTF sample of SNe Ia.
Reuses :class:`~uvex_transients.models.arnett.ArnettDecaySED`'s radioactive-decay Arnett diffusion and
floored-photosphere blackbody entirely; only :attr:`_DEFAULT_PARAMETERS` differs. The priors follow
:footcite:t:`sarin2026` (Sarin et al. 2026, a sample of 2205 SNe Ia from ZTF): ``M_Ni`` and ``M_ej``
are the population-level Gaussians from that paper's hierarchical Arnett-model fit
(:math:`\mu_\mathrm{Ni}=0.64\,M_\odot`, :math:`\sigma_\mathrm{Ni}=0.42\,M_\odot`;
:math:`\mu_\mathrm{ej}=1.26\,M_\odot`, :math:`\sigma_\mathrm{ej}=0.33\,M_\odot`), ``kappa_gamma`` is
fixed at the value adopted by :footcite:t:`scalzo2014` (Scalzo et al. 2014), and ``kappa`` is uniform
over that paper's marginalization range.
.. rubric:: Parameters
.. list-table::
:header-rows: 1
:widths: 18 18 64
* - Parameter
- Symbol
- Description
* - ``M_Ni``
- :math:`M_\mathrm{Ni}`
- Nickel-56 mass synthesized in the explosion.
* - ``M_ej``
- :math:`M_\mathrm{ej}`
- Ejecta mass.
* - ``v_ej``
- :math:`v_\mathrm{ej}`
- Ejecta velocity, taken to be constant and equal to the photospheric velocity.
* - ``kappa``
- :math:`\kappa`
- Grey optical opacity.
* - ``kappa_gamma``
- :math:`\kappa_\gamma`
- Opacity to high-energy photons. Fixed.
* - ``T_floor``
- :math:`T_\mathrm{floor}`
- Minimum photospheric temperature.
References
----------
.. footbibliography::
"""
_DEFAULT_PARAMETERS: ClassVar[dict[str, Parameter]] = {
"M_Ni": Parameter(
prior=TruncatedNormalPrior(mean=0.64, sigma=0.42, lower=0.05, upper=3.0),
scale=1 * u.Msun,
description="Nickel-56 mass synthesized in the explosion.",
latex=r"M_\mathrm{Ni}",
),
"M_ej": Parameter(
prior=TruncatedNormalPrior(mean=1.26, sigma=0.33, lower=0.05, upper=3.0),
scale=1 * u.Msun,
description="Ejecta mass.",
latex=r"M_\mathrm{ej}",
),
"v_ej": Parameter(
prior=NormalPrior(mean=11e3, sigma=1e3),
scale=1.0 * u.km / u.s,
description="Constant ejecta velocity, identified with the photospheric velocity.",
latex=r"v_\mathrm{ej}",
),
"kappa": Parameter(
prior=UniformPrior(lower=0.05, upper=0.15),
scale=1 * u.cm**2 / u.g,
description="Grey optical opacity.",
latex=r"\kappa",
),
"kappa_gamma": Parameter(
prior=ConstantPrior(value=0.03),
scale=1 * u.cm**2 / u.g,
description="Opacity to high-energy photons. Fixed (Scalzo+14).",
latex=r"\kappa_\gamma",
),
"T_floor": Parameter(
prior=TruncatedNormalPrior(mean=6000.0, sigma=1000.0, lower=3000.0, upper=10000.0),
scale=1 * u.K,
description="Minimum photospheric temperature.",
latex=r"T_\mathrm{floor}",
),
}
