"""
This module provides the `Kilonovae` class, a pre-defined Transient class. See the corresponding documentation page in "List of transient classes"
for more detail on this Transient class.
"""
import numpy as np
import sncosmo
from .core import Transient
from ..tools.utils import random_radec
RNG = np.random.default_rng()
[docs]
def read_possis_file(filename):
"""Read in a spectral model created by POSSIS (1906.04205).
This is as appropriate for injestion as a
`skysurvey.source.angular.AngularTimeSeriesSource`. Model grids can be
found here: https://github.com/mbulla/kilonova_models.
Parameters
----------
filename : str
Path to the POSSIS file.
Returns
-------
phase : `numpy.ndarray`
Phases in days.
wave : `numpy.ndarray`
Wavelengths in Angstroms.
cos_theta : `numpy.ndarray`
Cosine of viewing angle.
flux : `numpy.ndarray`
Model spectral flux density in arbitrary units. Must have shape
`(num_phases)`.
"""
f = open(filename)
lines = f.readlines()
nobs = int(lines[0])
nwave = float(lines[1])
line3 = (lines[2]).split(' ')
ntime = int(line3[0])
t_i = float(line3[1])
t_f = float(line3[2])
cos_theta = np.linspace(0, 1, nobs) # 11 viewing angles
phase = np.linspace(t_i, t_f, ntime) # epochs
file_ = np.genfromtxt(filename, skip_header=3)
wave = file_[0:int(nwave),0]
flux = []
for i in range(int(nobs)):
flux.append(file_[i*int(nwave):i*int(nwave)+int(nwave),1:])
flux = np.array(flux).T
phase = np.linspace(t_i, t_f, len(flux.T[0][0])) # epochs
return phase, wave, cos_theta, flux
[docs]
def get_kilonova_model(filename=None):
"""
Get a kilonova model from a POSSIS file.
Parameters
----------
filename : str, optional
Path to the POSSIS file. If None, it loads the default data file: ``nsns_nph1.0e+06_mejdyn0.020_mejwind0.130_phi30.txt``.
Returns
-------
`sncosmo.Model`
The initialized kilonova model with an angular-dependent source.
"""
from ..source.angular import AngularTimeSeriesSource
if filename is None:
import os
from .. import _PACKAGE_PATH
filename = os.path.join(_PACKAGE_PATH, "data", "nsns_nph1.0e+06_mejdyn0.020_mejwind0.130_phi30.txt")
phase, wave, cos_theta, flux = read_possis_file(filename)
source = AngularTimeSeriesSource(phase=phase, wave=wave, flux=flux, cos_theta=cos_theta,
name="kilonova")
model = sncosmo.Model(source)
return model
# =============== #
# #
# Kilonova #
# #
# =============== #
_KILONOVA_MODEL = get_kilonova_model()
[docs]
class Kilonova( Transient ):
"""
A class to model kilonovae.
Parameters
----------
_KIND : str, optional
The kind of transient. The default is "kilonova".
_TEMPLATE : sncosmo.Model, optional
The template to use. The default is a `sncosmo.Model` with a
`skysurvey.source.angular.AngularTimeSeriesSource` source.
_RATE : float, optional
The rate of kilonovae. The default is 1e3.
_MODEL : dict, optional
The model to use. The default is a dictionary with the following
keys:
- `t0`: The time of maximum of the kilonova.
- `redshift`: The redshift of the kilonova.
- `magabs`: The absolute magnitude of the kilonova.
- `magobs`: The observed magnitude of the kilonova.
- `amplitude`: The amplitude of the kilonova.
- `theta`: The viewing angle of the kilonova.
- `radec`: The ra and dec of the kilonova.
"""
_KIND = "kilonova"
_TEMPLATE = _KILONOVA_MODEL
_RATE = 1e3 # event per Gyr**3
_MODEL = dict( # when
t0 = {"func": RNG.uniform,
"kwargs": {"low":56_000, "high":56_200}
},
# what
redshift = {"kwargs":{"zmax":0.2}, "as":"z"},
magabs = {"func": RNG.normal,
"kwargs": {"loc": -18, "scale": 1}
},
magobs = {"func": "magabs_to_magobs",
"kwargs": {"z":"@z", "magabs": "@magabs"}
},
theta = {"func": RNG.uniform,
"kwargs": {"low":0., "high":90.}
},
# where
radec = {"func": random_radec,
"kwargs": {},
"as": ["ra","dec"]
},
)
