Spectral1D

class spectacle.modeling.Spectral1D(*args, **kwargs)

Bases: astropy.modeling.Fittable1DModel

Base representation of a compound model containing a variable number of OpticalDepth1D line model features.

Parameters

linesstr, OpticalDepth1D, list

The line information used to compose the spectral model. This can be either a string, in which case the line information is retrieve from the ion registry; an instance of OpticalDepth1D; or a list of either of the previous two types.

continuumFittable1DModel, optional

An astropy model representing the continuum of the spectrum. If not provided, a Const1D model is used.

zfloat, optional

The redshift applied to the spectral model. Default = 0.

lsfLSFModel, Kernel1D, str, optional

The line spread function applied to the spectral model. It can be a pre-defined kernel model, or a convolution kernel, or a string referencing the built-in Hubble COS lsf, or a Gaussian lsf. Optional keyword arguments can be passed through.

Attributes Summary

as_flux	New spectral model that produces flux output.
as_flux_decrement	New spectral model that produces flux decrement output.
as_optical_depth	New spectral model that produces optical depth output.
continuum
input_units	This property is used to indicate what units or sets of units the evaluate method expects, and returns a dictionary mapping inputs to units (or None if any units are accepted).
input_units_allow_dimensionless	Allow dimensionless input (and corresponding output).
input_units_equivalencies
inputs
is_single_ion	Whether this spectrum represents a collection of single ions or a collection of multiple different ions.
lines	The collection of profiles representing the absorption or emission lines in the spectrum model.
lsf_kernel
output_type	The data output of this spectral model.
outputs
redshift	The redshift at which the data given to.
rest_wavelength
velocity_convention

Methods Summary

__call__(self, x, \*args, \*\*kwargs)	Override the default call function to handle fixed parameters based on the unit of the provided dispersion.
evaluate(self, x, \*args, \*\*kwargs)	Evaluate the model on some input variables.
line_stats(self, x)	Calculate statistics over individual line profiles.
region_stats(self, x, rest_wavelength[, …])	Calculate statistics over arbitrary line regions given some tolerance from the continuum.
rejection_criteria(self, x, y[, auto_fit])	Implementation of the Akaike Information Criteria with Correction (AICC) (Akaike 1974; Liddle 2007; King et al.
with_continuum(self, continuum)	New spectral model defined with a different continuum.
with_line(self, \*args[, reset])	Add a new line to the spectral model.
with_lines(self, lines[, reset])	Create a new spectral model with the added lines.
with_lsf(self[, kernel])	New spectral model with a line spread function.
with_redshift(self, value)	Generate a new spectral model with the given redshift.

Attributes Documentation

as_flux

New spectral model that produces flux output.

as_flux_decrement

New spectral model that produces flux decrement output.

as_optical_depth

New spectral model that produces optical depth output.

continuum

input_units

This property is used to indicate what units or sets of units the evaluate method expects, and returns a dictionary mapping inputs to units (or None if any units are accepted).

Model sub-classes can also use function annotations in evaluate to indicate valid input units, in which case this property should not be overridden since it will return the input units based on the annotations.

input_units_allow_dimensionless

Allow dimensionless input (and corresponding output). If this is True, input values to evaluate will gain the units specified in input_units. If this is a dictionary then it should map input name to a bool to allow dimensionless numbers for that input. Only has an effect if input_units is defined.

input_units_equivalencies

inputs = ('x',)

is_single_ion

Whether this spectrum represents a collection of single ions or a collection of multiple different ions.

Returns

: bool

Is the spectrum composed of a collection of single ions.

lines

The collection of profiles representing the absorption or emission lines in the spectrum model.

Returns

: list

A list of Voigt1D models.

lsf_kernel

output_type

The data output of this spectral model. It could one of ‘flux’, ‘flux_decrement’, or ‘optical_depth’.

Returns

: str

The output type of the model.

outputs = ('y',)

redshift

The redshift at which the data given to.

Returns

: float

The redshift value.

rest_wavelength

velocity_convention

Methods Documentation

__call__(self, x, *args, **kwargs)

Override the default call function to handle fixed parameters based on the unit of the provided dispersion.

Notes

The initial call to this method from fitter will provide unit information on the dispersion. Subsequent calls do not. It is assumed that subsequent calls provide dispersion as km/s.

evaluate(self, x, *args, **kwargs)

Evaluate the model on some input variables.

line_stats(self, x)

Calculate statistics over individual line profiles.

Parameters

xQuantity

The input dispersion in either wavelength/frequency or velocity space.

Returns

tabQTable

A table detailing the calculated statistics.

region_stats(self, x, rest_wavelength, rel_tol=0.01, abs_tol=1e-05)

Calculate statistics over arbitrary line regions given some tolerance from the continuum.

Parameters

xQuantity

The input dispersion in either wavelength/frequency or velocity space.

rest_wavelengthQuantity

The rest frame wavelength used in conversions between wavelength/ frequency and velocity space.

rel_tolfloat

The relative tolerance parameter.

abs_tolfloat

The absolute tolerance parameter.

Returns

tabQTable

A table detailing the calculated statistics.

rejection_criteria(self, x, y, auto_fit=True)

Implementation of the Akaike Information Criteria with Correction (AICC) (Akaike 1974; Liddle 2007; King et al. 2011). Used to determine whether lines can be safely removed from the compound model without loss of information.

Parameters

xQuantity

The dispersion data.

yarray-like

The expected flux or tau data.

auto_fitbool

Whether the model fit should be re-evaluated for every removed line.

Returns

final_modelSpectral1D

The new spectral model with the least complexity.

with_continuum(self, continuum)

New spectral model defined with a different continuum.

with_line(self, *args, reset=False, **kwargs)

Add a new line to the spectral model.

Returns

: Spectral1D

The new spectral model.

with_lines(self, lines, reset=False)

Create a new spectral model with the added lines.

Parameters

lineslist

List of OpticalDepth1D line objects.

Returns

: Spectral1D

The new spectral model.

with_lsf(self, kernel=None, **kwargs)

New spectral model with a line spread function.

with_redshift(self, value)

Generate a new spectral model with the given redshift.