sample_photon
=============

.. py:function:: luminet.black_hole.sample_photon(min_r, max_r, incl, bh_mass, n)

   Sample a random photon from the accretion disk

   Each photon is a dictionary with the following properties:

   - ``radius``: radius of the photon on the accretion disk :math:`r`
   - ``alpha``: angle of the photon on the accretion disk :math:`\alpha`
   - ``impact_parameter``: impact parameter of the photon :math:`b`
   - ``z_factor``: redshift factor of the photon :math:`1+z`

   This function is used in :meth:`~luminet.black_hole.BlackHole.sample_photons` to sample
   photons on the accretion disk of a black hole in a parallellized manner.

   .. attention::

      Photons are not sampled uniformly on the accretion disk, but biased towards the center.
      Black holes have more flux delta towards the center, and thus we need more precision there.
      This makes the triangulation with hollow mask in the center also very happy.

   :Parameters: * **min_r** -- minimum radius of the accretion disk
                * **max_r** -- maximum radius of the accretion disk
                * **incl** -- inclination of the observer wrt the disk
                * **bh_mass** -- mass of the black hole
                * **n** -- order of the isoradial

   :returns: *Dict* -- Dictionary containing all basic properties of a single photon from the accretion disk.