.. _physics-radiativeTransferSource:

Radiative Transfer Photon Sources
=================================

Class providing photon sources for Monte Carlo radiative transfer calculations---objects that emit photon packets into the computational domain. Each implementation describes a specific type of radiation source (e.g.\ a point source, a stellar population, an AGN, or a uniform field) and provides the luminosity spectrum (in :math:`L_\odot` \AA\ :math:`^{-1}`), the integrated luminosity over a wavelength range, and a method to initialize photon packet properties (wavelength, position, direction, and luminosity weight) drawn from the source's spatial and spectral distribution.

**Default implementation:** ``radiativeTransferSourcePoint``

Methods
-------

``initializePhotonPacket`` → ``void``
   Initialize a photon packet from the source.

   * ``class(radiativeTransferPhotonPacketClass), intent(inout) :: photonPacket``

``spectrum`` → ``double precision``
   Return the spectrum (in units of :math:`L_\odot` \AA\ :math:`^{-1}`) of the source at the given ``wavelength``.

   * ``double precision, intent(in ) :: wavelength``

   * ``integer , intent(in ), optional :: sourceType``

``luminosity`` → ``double precision``
   Return the luminosity (in units of :math:`L_\odot`) of the source at the given wavelength range.

   * ``double precision, intent(in ) :: wavelengthMinimum, wavelengthMaximum``

   * ``integer , intent(in ), optional :: sourceType``

``sourceTypeCount`` → ``integer``
   Return the number of source types.

``sourceTypeName`` → ``type(varying_string)``
   Return the name of the requested of source type.

   * ``integer, intent(in ) :: sourceType``

.. _physics-radiativeTransferSourceDistributed:

``radiativeTransferSourceDistributed``
--------------------------------------

A photon source class for spatially extended radiative transfer sources whose emission is distributed according to a specified mass distribution. Photon packets are launched from positions sampled from the mass distribution, with spectra and a descriptive label provided via the ``[radiativeTransferSpectrum]`` object and ``[label]`` parameter.

**Parameters**

* ``[position]`` (default ``[0.0d0,0.0d0,0.0d0]``) — The position of the distributed source.
* ``[label]`` (default ``var_str('unknown')``) — A descriptive label for the source.

.. _physics-radiativeTransferSourcePoint:

``radiativeTransferSourcePoint``
--------------------------------

A photon source class for unresolved point-like radiative transfer sources that emit isotropically from a fixed location in three-dimensional space. The source position and a descriptive label are given by the ``[position]`` and ``[label]`` parameters, and the spectral shape is provided via the ``[radiativeTransferSpectrum]`` object.

**(Default implementation)**

**Parameters**

* ``[position]`` (default ``[0.0d0,0.0d0,0.0d0]``) — The position of the point source.
* ``[label]`` (default ``var_str('unknown')``) — A descriptive label for the source.

.. _physics-radiativeTransferSourceSummation:

``radiativeTransferSourceSummation``
------------------------------------

A photon source class for summation sources.

**Methods**

* ``list`` — Return a list of all sub-components.