.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "modeling/gallery/spectral/plot_absorbed.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

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

        Click :ref:`here <sphx_glr_download_modeling_gallery_spectral_plot_absorbed.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_modeling_gallery_spectral_plot_absorbed.py:


.. _absorption-spectral-model:

EBL absorbption spectral model
==============================

This model evaluates absorbed spectral model.

The EBL absorption factor given by

.. math::
    \exp{ \left ( -\alpha \times \tau(E, z) \right )}

where :math:`\tau(E, z)` is the optical depth predicted by the model
(`~gammapy.modeling.models.Absorption`), which depends on the energy of the gamma-rays and the
redshift z of the source, and :math:`\alpha` is a scale factor
(default: 1) for the optical depth.

.. GENERATED FROM PYTHON SOURCE LINES 21-24

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

.. GENERATED FROM PYTHON SOURCE LINES 24-77

.. code-block:: default


    from astropy import units as u
    import matplotlib.pyplot as plt
    from gammapy.modeling.models import (
        EBLAbsorptionNormSpectralModel,
        Models,
        PowerLawSpectralModel,
        SkyModel,
    )

    # Here we illustrate how to create and plot EBL absorption models for a redshift of 0.5
    # sphinx_gallery_thumbnail_number = 1

    redshift = 0.5
    dominguez = EBLAbsorptionNormSpectralModel.read_builtin("dominguez", redshift=redshift)
    franceschini = EBLAbsorptionNormSpectralModel.read_builtin(
        "franceschini", redshift=redshift
    )
    finke = EBLAbsorptionNormSpectralModel.read_builtin("finke", redshift=redshift)

    plt.figure()
    energy_bounds = [0.08, 3] * u.TeV
    opts = dict(energy_bounds=energy_bounds, xunits=u.TeV)
    franceschini.plot(label="Franceschini 2008", **opts)
    finke.plot(label="Finke 2010", **opts)
    dominguez.plot(label="Dominguez 2011", **opts)

    plt.ylabel(r"Absorption coefficient [$\exp{(-\tau(E))}$]")
    plt.xlim(energy_bounds.value)
    plt.ylim(1e-4, 2)
    plt.title(f"EBL models (z={redshift})")
    plt.grid(which="both")
    plt.legend(loc="best")


    # Spectral model corresponding to PKS 2155-304 (quiescent state)
    index = 3.53
    amplitude = 1.81 * 1e-12 * u.Unit("cm-2 s-1 TeV-1")
    reference = 1 * u.TeV
    pwl = PowerLawSpectralModel(index=index, amplitude=amplitude, reference=reference)

    # The power-law model is multiplied by the EBL norm spectral model
    redshift = 0.117
    absorption = EBLAbsorptionNormSpectralModel.read_builtin("dominguez", redshift=redshift)

    model = pwl * absorption

    energy_bounds = [0.1, 100] * u.TeV
    plt.figure()
    model.plot(energy_bounds)
    plt.grid(which="both")
    plt.ylim(1e-24, 1e-8)




.. rst-class:: sphx-glr-horizontal


    *

      .. image-sg:: /modeling/gallery/spectral/images/sphx_glr_plot_absorbed_001.png
         :alt: EBL models (z=0.5)
         :srcset: /modeling/gallery/spectral/images/sphx_glr_plot_absorbed_001.png
         :class: sphx-glr-multi-img

    *

      .. image-sg:: /modeling/gallery/spectral/images/sphx_glr_plot_absorbed_002.png
         :alt: plot absorbed
         :srcset: /modeling/gallery/spectral/images/sphx_glr_plot_absorbed_002.png
         :class: sphx-glr-multi-img





.. GENERATED FROM PYTHON SOURCE LINES 78-81

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

.. GENERATED FROM PYTHON SOURCE LINES 81-86

.. code-block:: default


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

    print(models.to_yaml())




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

 Out:

 .. code-block:: none

    components:
    -   name: absorbed-model
        type: SkyModel
        spectral:
            type: CompoundSpectralModel
            model1:
                type: PowerLawSpectralModel
                parameters:
                -   name: index
                    value: 3.53
                -   name: amplitude
                    value: 1.81e-12
                    unit: cm-2 s-1 TeV-1
                -   name: reference
                    value: 1.0
                    unit: TeV
                    frozen: true
            model2:
                type: EBLAbsorptionNormSpectralModel
                parameters:
                -   name: alpha_norm
                    value: 1.0
                    frozen: true
                -   name: redshift
                    value: 0.117
                    frozen: true
                filename: /Users/adonath/github/gammapy/gammapy-data/ebl/ebl_dominguez11.fits.gz
            operator: mul






.. _sphx_glr_download_modeling_gallery_spectral_plot_absorbed.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_absorbed.py <plot_absorbed.py>`



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

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


.. only:: html

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

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