.. _physics-hotHaloRamPressureStripping:

Hot Halo Ram Pressure Stripping
===============================

Class providing models of the stripping radius (in Mpc) to which the hot gas atmosphere of a satellite galaxy is removed by ram pressure from the host halo. The stripping radius is set by the balance between the ram pressure force and the restoring gravitational force of the satellite; gas outside this radius is assumed to be stripped and added to the host hot gas reservoir. This process progressively depletes the satellite's hot gas supply, suppressing its cooling and star formation ("strangulation").

**Default implementation:** ``hotHaloRamPressureStrippingFont2008``

Methods
-------

``radiusStripped`` → ``double precision``
   Return the radius to which ``node`` is stripped due to ram pressure from its host halo (in units of Mpc).

   * ``type(treeNode), intent(inout), target :: node``

.. _physics-hotHaloRamPressureStrippingFont2008:

``hotHaloRamPressureStrippingFont2008``
---------------------------------------

A hot halo ram pressure stripping class based on the methods of :cite:t:`font_colours_2008`. Specifically, the radius, :math:`r_\mathrm{rp}`, is computed as the solution of

.. math::

   \alpha_\mathrm{rp} {\mathrm{G} M_\mathrm{satellite}(r_\mathrm{rp}) \rho_\mathrm{hot, satellite}(r_\mathrm{rp}) \over
   r_\mathrm{rp} } = \mathcal{F}_\mathrm{ram, hot, host},

where :math:`M_\mathrm{satellite}(r)` is the total mass of the satellite within radius :math:`r`, :math:`\mathcal{F}_\mathrm{ram, hot, host}` is the ram pressure force due to the hot halo (computed using the selected hot halo ram pressure force method; see :galacticus-class:`hotHaloRamPressureForce`). The parameter :math:`\alpha_\mathrm{rp}=`\ ``[formFactor]`` is a geometric factor of order unity.

**(Default implementation)**

**Parameters**

* ``[formFactor]`` (default ``2.0d0``) — The form factor appearing in the gravitational binding force (per unit area) in the ram pressure stripping model of :cite:author:`font_colours_2008` (:cite:year:`font_colours_2008`; their eqn. 4).
* ``[solverFailureIsFatal]`` (default ``.true.``) — If true, failure to bracket the ram pressure radius is fatal.

.. _physics-hotHaloRamPressureStrippingVirialRadius:

``hotHaloRamPressureStrippingVirialRadius``
-------------------------------------------

A hot halo ram pressure stripping class which sets the ram pressure stripping radius equal to the virial radius of the halo. The effectively results in no ram pressure stripping.

**Parameters**

* ``[coreRadiusOverVirialRadius]`` (default ``0.3d0``) — The core radius in the hot halo density profile in units of the virial radius.