def setUp(self):
self.search_keys = []
self.parameters = dict()
self.component_mass_pars = dict(mass_1=1.4, mass_2=1.4)
self.mass_parameters = self.component_mass_pars.copy()
self.mass_parameters[
"mass_ratio"] = conversion.component_masses_to_mass_ratio(
**self.component_mass_pars)
self.mass_parameters[
"symmetric_mass_ratio"] = conversion.component_masses_to_symmetric_mass_ratio(
**self.component_mass_pars)
self.mass_parameters[
"chirp_mass"] = conversion.component_masses_to_chirp_mass(
**self.component_mass_pars)
self.mass_parameters[
"total_mass"] = conversion.component_masses_to_total_mass(
**self.component_mass_pars)
self.component_tidal_parameters = dict(lambda_1=300, lambda_2=300)
self.all_component_pars = self.component_tidal_parameters.copy()
self.all_component_pars.update(self.component_mass_pars)
self.tidal_parameters = self.component_tidal_parameters.copy()
self.tidal_parameters[
"lambda_tilde"] = conversion.lambda_1_lambda_2_to_lambda_tilde(
**self.all_component_pars)
self.tidal_parameters[
"delta_lambda_tilde"] = conversion.lambda_1_lambda_2_to_delta_lambda_tilde(
**self.all_component_pars)
def SPA_time_shift(frequency_array, mass_1, mass_2, mode=(2, 2), to_order=8):
'''
Calculate t(f) of stationary phase approximation(SPA) for a special spherical harmonic mode of GW.
See (A12) in Niu, arXiv:1910.10592
Args
frequency_array: (1d array): frequency array, unit:Hz
mass_1, mass_2 (float): masses of the compact binary, unit: solar mass
mode (Tuple[int]): harmonic mode of GW, default to be (2, 2)
to_order (int): specifying to which order the SPA takes, 1-8, default to be 8
Returns
1d array: time array t(f)
'''
gamma = 0.5772
total_mass = (mass_1 + mass_2) * M_sun
chirp_mass = component_masses_to_chirp_mass(mass_1, mass_2) * M_sun
eta = component_masses_to_symmetric_mass_ratio(mass_1, mass_2)
l, m = mode
f = 2 * frequency_array / m
v = (G * total_mass * np.pi * frequency_array / c**3)**(1 / 3)
v = v.astype('float64')
tau = [1,
0,
743 / 252 + 11 / 3 * eta,
-32 / 5 * np.pi,
3058673 / 508032 + 5429 / 504 * eta + 617 / 72 * eta**2,
(-7729 / 252 + 13 / 3 * eta) * np.pi,
-10052469856691 / 23471078400 + 128 / 3 * np.pi**2 + 6848 / 105 * gamma + (3147553127 / 3048192 - 451 / 12 * np.pi**2) * eta -
15211 / 1728 * eta**2 + 25565 / 1296 *
eta**3 + 3424 / 105 * np.log(16 * v**2),
(-15419335 / 127008 - 75703 / 756 * eta + 14809 / 378 * eta**2) * np.pi]
t_shift = -5/256 * (G * chirp_mass)**(-5 / 3) * c**5 * (np.pi * f)**(-8 / 3) * \
sum([tau_i * v**i for i, tau_i in enumerate(tau[:to_order])])
t_shift = t_shift.astype('float64')
return t_shift
def test_component_masses_to_symmetric_mass_ratio(self):
symmetric_mass_ratio = conversion.component_masses_to_symmetric_mass_ratio(self.mass_1, self.mass_2)
self.assertAlmostEqual(self.symmetric_mass_ratio, symmetric_mass_ratio)