.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        Click :ref:`here <sphx_glr_download_modeling_gallery_spectral_plot_template_spectral.py>`     to download the full example code
    .. rst-class:: sphx-glr-example-title

    .. _sphx_glr_modeling_gallery_spectral_plot_template_spectral.py:


.. _template-spectral-model:

Template Spectral Model
=======================

This model is defined by custom tabular values.

The units returned will be the units of the values array provided at
initialization. The model will return values interpolated in
log-space, returning 0 for energies outside of the limits of the provided
energy array.

The class implementation follows closely what has been done in
`naima.models.TemplateSpectralModel`

Example plot
------------
Here is an example plot of the model:


.. code-block:: default


    import numpy as np
    from astropy import units as u
    import matplotlib.pyplot as plt







Spectral correction
Corrections to templates can be applied by multiplication with a normalized spectral model,
for example `gammapy.modeling.models.PowerLawNormSpectralModel`.
This operation create a new `gammapy.modeling.models.CompoundSpectralModel`



.. code-block:: default

    from gammapy.modeling.models import (
        Models,
        PowerLawNormSpectralModel,
        SkyModel,
        TemplateSpectralModel,
    )

    energy_range = [0.1, 1] * u.TeV
    energy = np.array([1e6, 3e6, 1e7, 3e7]) * u.MeV
    values = np.array([4.4e-38, 2.0e-38, 8.8e-39, 3.9e-39]) * u.Unit("MeV-1 s-1 cm-2")
    template = TemplateSpectralModel(energy=energy, values=values)
    template.plot(energy_range)
    plt.grid(which="both")


    new_model = template * PowerLawNormSpectralModel(norm=2, tilt=0)

    print(new_model)




.. image:: /modeling/gallery/spectral/images/sphx_glr_plot_template_spectral_001.png
    :alt: plot template spectral
    :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 Out:

 .. code-block:: none

    CompoundSpectralModel
        Component 1 : TemplateSpectralModel

        Component 2 : PowerLawNormSpectralModel

       name     value    unit min max frozen   error  
    --------- ---------- ---- --- --- ------ ---------
         norm 2.0000e+00      nan nan  False 0.000e+00
         tilt 0.0000e+00      nan nan   True 0.000e+00
    reference 1.0000e+00  TeV nan nan   True 0.000e+00
        Operator : mul





YAML representation
-------------------
Here is an example YAML file using the model:


.. code-block:: default


    model = SkyModel(spectral_model=template, name="template-model")
    models = Models([model])

    print(models.to_yaml())




.. rst-class:: sphx-glr-script-out

 Out:

 .. code-block:: none

    components:
    -   name: template-model
        type: SkyModel
        spectral:
            type: TemplateSpectralModel
            energy:
                data:
                - 1000000.0
                - 3000000.0
                - 10000000.0
                - 30000000.0
                unit: MeV
            values:
                data:
                - 4.4e-38
                - 2.0e-38
                - 8.8e-39
                - 3.9e-39
                unit: 1 / (cm2 MeV s)






.. _sphx_glr_download_modeling_gallery_spectral_plot_template_spectral.py:


.. only :: html

 .. container:: sphx-glr-footer
    :class: sphx-glr-footer-example



  .. container:: sphx-glr-download sphx-glr-download-python

     :download:`Download Python source code: plot_template_spectral.py <plot_template_spectral.py>`



  .. container:: sphx-glr-download sphx-glr-download-jupyter

     :download:`Download Jupyter notebook: plot_template_spectral.ipynb <plot_template_spectral.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_