lightcurvelynx.astro_utils.snia_utils

Classes

`HostmassX1Distr`	A class that contains the pdf of the SALT x1 parameter given the hostmass
`HostmassX1Func`	A class for sampling from the HostmassX1Distr.
`X0FromDistMod`	A wrapper class for the _x0_from_distmod() function.
`DistModFromRedshift`	A wrapper class for the _distmod_from_redshift() function.
`SNCoordGivenPhysicalSep`	A class for gernerating SN Coordinates given host coordinates and physical separations.

Functions

`snia_volumetric_rates`(redshift[, r0, alpha])	SN Ia volumetric rate.
`num_snia_per_redshift_bin`([zmin, zmax, znbins, ...])	Calculate the number of SNe Ia in each redshift bin based on rates.

Module Contents

snia_volumetric_rates(redshift, r0=2.27e-05, alpha=1.7)[source]

SN Ia volumetric rate. r_v(z) = r0 * (1+z)^alpha （SNe Ia yr^-1 Mpc^-3 h_70^3） The default values are from Frohmaier et al. (2019). r0 = 2.27+/-0.19e-5 alpha = 1.7+/-0.21

Parameters:

redshift (float or numpy.ndarray) – The redshift of the supernova
r0 (float) – The rate function parameter r0. Default is 2.27e-5.
alpha (float) – The rate function parameter alpha. Default is 1.7

Returns:

rate_vol – The volumetric rate of the supernova given the redshift

Return type:

float or numpy.ndarray

num_snia_per_redshift_bin(zmin=0.001, zmax=10, znbins=20, solid_angle=None, H0=73.0, Omega_m=0.3, vol_rate_function=snia_volumetric_rates)[source]

Calculate the number of SNe Ia in each redshift bin based on rates.

Calculated using:

r_v(z) = dN/dz
V = comoving volume
T = length of survey in years
N = int r_v(z)dz * dV * dT

Parameters:

zmin (float) – Min redshift value for calculation.
zmax (float) – Max redshift value for calculation.
znbins (int) – Number of redshift bins for calculating SNe Ia numbers.
solid_angle (float) – Solid angle for calculating the number of SNe (in sr).
H0 (float) – The Hubble Constant.
Omega_m (float) – The matter density.
vol_rate_function (Callable) – The function that defines the volumetric rate. Default is snia_volumetric_rates.

Returns:

num_sn (numpy.ndarray) – Number of SNe Ia in each zbin per year.
z_mean (numpy.ndarray) – Mean value for each redshift bin.

class HostmassX1Distr(hostmass)[source]

A class that contains the pdf of the SALT x1 parameter given the hostmass

hostmass[source]

The hostmass value in units of log10(M/M_solar).

Type:: float

Parameters:: hostmass (float) – The hostmass value in units of log10(M/M_solar).

hostmass[source]

pdf(x1)[source]

The pdf of x1 given hostmass.

Parameters:

x1 (numpy.ndarray) – The x1 value.
hostmass (float) – The hostmass value in units of log10(M/M_solar).

Return type:

The pdf function of x1 given hostmass.

class HostmassX1Func(hostmass, **kwargs)[source]

Bases: lightcurvelynx.math_nodes.scipy_random.NumericalInversePolynomialFunc

A class for sampling from the HostmassX1Distr.

Parameters:

hostmass (function or constant) – The function or constant providing the hostmass value in units of log10(M/M_solar).
**kwargs (dict, optional) – Any additional keyword arguments.

compute(graph_state, rng_info=None, **kwargs)[source]

Sample from one of the two distributions depending on hostmass.

Parameters:

graph_state (GraphState) – An object mapping graph parameters to their values. This object is modified in place as it is sampled.
rng_info (numpy.random._generator.Generator or None, optional) – A given numpy random number generator to use for this computation. If not provided, the function uses the node’s random number generator.
**kwargs (dict, optional) – Additional function arguments.

Returns:

results – The result of the computation. This return value is provided so that testing functions can easily access the results.

Return type:

any

class X0FromDistMod(distmod, x1, c, alpha, beta, m_abs, **kwargs)[source]

Bases: lightcurvelynx.base_models.FunctionNode

A wrapper class for the _x0_from_distmod() function.

Parameters:

distmod (function or constant) – The function or constant providing the distance modulus value.
x1 (function or constant) – The function or constant providing the x1 value.
c (function or constant) – The function or constant providing the c value.
alpha (function or constant) – The function or constant providing the alpha value.
beta (function or constant) – The function or constant providing the beta value.
m_abs (function or constant) – The function or constant providing the m_abs value.
**kwargs (dict, optional) – Any additional keyword arguments.

class DistModFromRedshift(redshift, H0=73.0, Omega_m=0.3, **kwargs)[source]

Bases: lightcurvelynx.base_models.FunctionNode

A wrapper class for the _distmod_from_redshift() function.

Parameters:

redshift (function or constant) – The function or constant providing the redshift value.
H0 (constant) – The Hubble constant.
Omega_m (constant) – The matter density Omega_m.
**kwargs (dict, optional) – Any additional keyword arguments.

cosmo[source]

class SNCoordGivenPhysicalSep(host_ra, host_dec, physical_sep_kpc, redshift, *, H0=73.0, Omega_m=0.3, pos_angle=None, **kwargs)[source]

Bases: lightcurvelynx.base_models.FunctionNode

A class for gernerating SN Coordinates given host coordinates and physical separations.

Parameters:

host_ra (function or constant) – Host galaxy RA in degree.
host_dec (function or constant) – Host galaxy DEC in degree.
physical_sep_kpc (function or constant) – The physical separation between host and SN in kpc.
redshift (function or constant) – The function or constant providing the redshift value.
H0 (constant) – The Hubble constant.
Omega_m (constant) – The matter density Omega_m.
pos_angle (parameter or None) – The position angle for the SN location relative to the host galaxy (in radians). If None, a random position angle is generated for each sample.
**kwargs (dict, optional) – Any additional keyword arguments.

cosmo[source]