Tutorial
=========

.. _idPIE_tutorial:

Use ``idPIE`` X-ray profiles.
-----------------------------

To use ``idPIE`` profiles, one must choose which ``dPIE`` profiles are considered to trace the X-ray signal.
The ``idPIE`` profiles use the same parameters as the ``dPIE`` profiles, but convert them into their corresponding hydrostatic ICM density, and computes the expected X-ray signal. The joint optimisation of selected profiles yields additional constraints.
In practice, ``dPIE`` profiles (id:``81``) are co-optimised with X-ray using ``idPIE`` profiles if keyword ``X-ray   2`` is added to the profile script.

For instance:

.. code-block:: console

	potential O1
		profile          81
		X-ray	         2
		x_centre         0.
		y_centre         0.
		ellipticity      0.5
		angle_pos        0.
		core_radius_kpc  100
		cut_radius_kpc   2500.
		v_disp           1000.
		z_lens           0.3
		end
	limit O1
		x_centre         1 -10. 5. 0.01
		cut_radius_kpc   1 500. 10000. 100.
		end



This requires to format include the ``X-ray`` section:

.. code-block:: console

	X-ray
		pixel_area      0.00107584
		Chandra         1
		Optimization    1
		Optimization_z  0.4
		Temp0           13.4        # in keV
		Jz_array        1 polyE Jz_polyE_z0.4000.csv
		Type_factor_likelihood   1
		factor_cash     252.2
		constant_cash   0.
		bkg_map         3 bkg_map.fits
		count_map       3 count_map.fits
		exposure_map    3 exposure_map.fits
		end
		
where keywords ``Temp0`` and ``Jz_array`` are proper to these hydrostatic X-ray profiles.

``Temp0`` is the pivot temperature model, eq. (17) in 
`Allingham+23b <https://arxiv.org/abs/2309.07076>`_:
:math:`T_0(z) = T_{500,c} (z) T_{\rm ref}`.
It may be computed using routine ``predT``:

.. code-block:: console
	
	predT0 <redshift> <model_type> <M_500,c>
	
where the mass
:math:`M_{500,c}` is in
:math:`M_{\odot}`, and the ``<model_type>`` corresponds to the regression used for
:math:`P_e (n_e)`. By defult, use ``polyEv1`` for the latter.

``Jz_array`` indicates how to compute the Jz function, relating the potential to the ICM density 
:math:`n_e`. 
It takes three arguments:

- An integer. ``0``: do not perform the computation. ``1``: perform it.

- A string for the model type. By default, use ``polyE``. Other option is ``polyA``, which should be more up-to-date.

- A second string for the name of the output array. If the array is not computed (``0``), this array must already exist.