BlackBody¶
-
class
astropy.modeling.physical_models.
BlackBody
(temperature=<Quantity 5000. K>, scale=1.0, **kwargs)[source]¶ Bases:
astropy.modeling.Fittable1DModel
Blackbody model using the Planck function.
Notes
Model formula:
\[B_{\nu}(T) = A \frac{2 h \nu^{3} / c^{2}}{exp(h \nu / k T) - 1}\]Examples
>>> from astropy.modeling import models >>> from astropy import units as u >>> bb = models.BlackBody(temperature=5000*u.K) >>> bb(6000 * u.AA) <Quantity 1.53254685e-05 erg / (cm2 Hz s sr)>
import numpy as np import matplotlib.pyplot as plt from astropy.modeling.models import BlackBody from astropy import units as u from astropy.visualization import quantity_support bb = BlackBody(temperature=5778*u.K) wav = np.arange(1000, 110000) * u.AA flux = bb(wav) with quantity_support(): plt.figure() plt.semilogx(wav, flux) plt.axvline(bb.nu_max.to(u.AA, equivalencies=u.spectral()).value, ls='--') plt.show()
Attributes Summary
Bolometric flux.
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).Peak wavelength when the curve is expressed as power density.
Peak frequency when the curve is expressed as power density.
Names of the parameters that describe models of this type.
Methods Summary
evaluate
(x, temperature, scale)Evaluate the model.
Attributes Documentation
-
bolometric_flux
¶ Bolometric flux.
-
input_units
¶
-
input_units_equivalencies
= {'x': [(Unit("m"), Unit("Hz"), <function spectral.<locals>.<lambda>>), (Unit("m"), Unit("J"), <function spectral.<locals>.<lambda>>), (Unit("Hz"), Unit("J"), <function spectral.<locals>.<lambda>>, <function spectral.<locals>.<lambda>>), (Unit("m"), Unit("1 / m"), <function spectral.<locals>.<lambda>>), (Unit("Hz"), Unit("1 / m"), <function spectral.<locals>.<lambda>>, <function spectral.<locals>.<lambda>>), (Unit("J"), Unit("1 / m"), <function spectral.<locals>.<lambda>>, <function spectral.<locals>.<lambda>>), (Unit("1 / m"), Unit("rad / m"), <function spectral.<locals>.<lambda>>, <function spectral.<locals>.<lambda>>), (Unit("m"), Unit("rad / m"), <function spectral.<locals>.<lambda>>), (Unit("Hz"), Unit("rad / m"), <function spectral.<locals>.<lambda>>, <function spectral.<locals>.<lambda>>), (Unit("J"), Unit("rad / m"), <function spectral.<locals>.<lambda>>, <function spectral.<locals>.<lambda>>)]}¶
-
lambda_max
¶ Peak wavelength when the curve is expressed as power density.
-
nu_max
¶ Peak frequency when the curve is expressed as power density.
-
param_names
= ('temperature', 'scale')¶ Names of the parameters that describe models of this type.
The parameters in this tuple are in the same order they should be passed in when initializing a model of a specific type. Some types of models, such as polynomial models, have a different number of parameters depending on some other property of the model, such as the degree.
When defining a custom model class the value of this attribute is automatically set by the
Parameter
attributes defined in the class body.
-
scale
= Parameter('scale', value=1.0, bounds=(0, None))¶
-
temperature
= Parameter('temperature', value=5000.0, unit=K, bounds=(0, None))¶
Methods Documentation
-
evaluate
(x, temperature, scale)[source]¶ Evaluate the model.
- Parameters
- Returns
- ynumber or ndarray
Blackbody spectrum. The units are determined from the units of
scale
.
Note
Use
numpy.errstate
to suppress Numpy warnings, if desired.Warning
Output values might contain
nan
andinf
.- Raises
- ValueError
Invalid temperature.
- ZeroDivisionError
Wavelength is zero (when converting to frequency).
-