Help on class PowerLawRates in module snsims.paramDistribution:
class PowerLawRates(snsims.populationParamSamples.RateDistributions)
| This class is a concrete implementation of `RateDistributions` with the
| following properties:
| - The SN rate : The SN rate is a single power law with numerical
| coefficients (alpha, beta) passed into the instantiation. The rate is
| the number of SN at redshift z per comoving volume per unit observer
| time over the entire sky expressed in units of numbers/Mpc^3/year
| - A binning in redshift is used to perform the calculation of numbers of SN.
| This is assumed
| - The expected number of SN in each of these redshift bins is computed using
| the rate above, and a cosmology to compute the comoving volume for the
| redshift bin
| - The numbers of SN are determined by a Poisson Distribution about the
| expected number in each redshift bin, determined with a random state
| passed in as an argument. This number must be integral.
| - It is assumed that the change of rates and volume within a redshift bin
| is negligible enough that samples to the true distribution may be drawn
| by obtaining number of SN samples of z from a uniform distribution
| within the z bin.
|
| Method resolution order:
| PowerLawRates
| snsims.populationParamSamples.RateDistributions
| __builtin__.object
|
| Methods defined here:
|
| __init__(self, rng, alpha=2.6e-05, beta=1.5, zbinEdges=None, zlower=1e-08, zhigher=1.4, numBins=20, surveyDuration=10.0, fieldArea=None, skyFraction=None, cosmo=FlatLambdaCDM(name="Planck15", H0=67.7 km / (Mpc...ff=3.05, m_nu=[ 0. 0. 0.06] eV, Ob0=0.0486))
| Parameters
| ----------
| rng : instance of `np.random.RandomState`
| cosmo : Instance of `astropy.cosmology` class, optional, defaults to Planck15
| data structure specifying the cosmological parameters
| alpha : float, optional, defaults to 2.6e-5
| beta : float, optional, defaults to 1.5
| parameter in expression
|
| numSN(self)
| Return the number of expected supernovae in time DeltaT, with a rate snrate
| in a redshift range zlower, zhigher divided into numBins equal redshift
| bins. The variation of the rate within a bin is ignored.
|
| Parameters
| ----------
| zlower : mandatory, float
| lower limit on redshift range
| zhigher : mandatory, float
| upper limit on redshift range
| numBins : mandatory, integer
| number of bins
| cosmo : `astropy.cosmology` instance, mandatory
| cosmological parameters
| fieldArea : mandatory, units of radian square
| sky area considered
|
| snRate(self, z)
| The rate of SN at a redshift z in units of number of SN/ comoving
| volume in Mpc^3/yr in earth years according to the commonly used
| power-law expression
|
| .. math:: rate(z) = lpha (h/0.7)^3 (1.0 + z)eta
|
| Parameters
| ----------
| z : array-like, mandatory
| redshifts at which the rate is evaluated
|
| Examples
| --------
|
| zSampleSize(self)
| Parameters
| ----------
| zbinEdges : `nunpy.ndarray` of edges of zbins, defaults to None
| Should be of the form np.array([z0, z1, z2]) which will have
| zbins (z0, z1) and (z1, z2)
| skyFraction : np.float, optional,
| fieldArea : optional, units of degrees squared
| area of sky considered.
| zlower : float, optional, defaults to None
| lower edge of z range
| zhigher : float, optional, defaults to None
| higher edge of z range
| numBins : int, optional, defaults to None
| if not None, overrides zbinEdges
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| randomState
|
| skyFraction
|
| zSamples
|
| zbinEdges
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| __abstractmethods__ = frozenset([])
|
| ----------------------------------------------------------------------
| Data descriptors inherited from snsims.populationParamSamples.RateDistributions:
|
| __dict__
| dictionary for instance variables (if defined)
|
| __weakref__
| list of weak references to the object (if defined)