.. _compton:


Inverse Compton
===============

Two different Compton processes are considered:

- **synchrotron self Compton (SSC)**, implemented in :class:`~agnpy.compton.SynchrotronSelfCompton`, considering as target for the inverse Compton the synchrotron photons produced in the blob by the accelerated electrons (based on [DermerMenon2009]_ and [Finke2008]_); 

- **external Compton (EC)**, implemented in :class:`~agnpy.compton.ExternalCompton`, considering as a target for the inverse Compton the (direct and reprocessed) photon fields generated by the accretion phenomena (based on [Dermer2009]_ and [Finke2016]_). 


Synchrotron Self Compton
------------------------
The synchrotron self Compton radiation calculation works exactly as the :ref:`synchrotron` one.
The instance of the emission region has to be passed to the radiative class initialiser.
SED can be evaluated over an array of frequencies with the ``sed_flux`` method.

.. plot:: snippets/ssc_snippet.py
   :include-source:


External Compton
----------------
As an example of this process, let us consider Compton scattering of the photon field produced by the broad line region by a power-law electron distribution.

.. plot:: snippets/ec_snippet.py
   :include-source:

As we can see from the snippet, the EC radiation can be computed passing to the :class:`~agnpy.compton.ExternalCompton` 
class

- the instance of the emission region (:class:`~agnpy.emission_regions.Blob`); 
- the instance of the target (:class:`~agnpy.targets.SphericalShellBLR`);
- the distance between the blob and the target photon field (``r``).

You can use any object in the :py:mod:`~agnpy.targets` module as target for external Compton.
For more examples of Inverse Compton radiation and reproduction of literature results, 
check the `tutorial notebook on external Compton <tutorials/external_compton.html>`_.