.. include:: ../../wlsubstitutions.rst
.. _CovarTwoPCFWLShearShear2D:

Output Product: Covariance of Tomographic Cosmic Shear Correlation
======================================================================

$SetSchemaPath le3/wl/cmtwopcf/out/euc-le3-wl-cmtwopcf-ShearShear2D.xsd

Data Product Name
___________________
.. DataProductNameStart

$PrintDataProductName

.. DataProductNameEnd

Data Product Custodian
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.. DataProductCustodianStart

$PrintDataProductCustodian

.. DataProductCustodianEnd

Name of the Schema File
__________________________
.. NameSchemaStart

$PrintSchemaFilename

.. NameSchemaEnd

Last Edited for DPDD Version
______________________________
.. DpddVersionlTagStart

1.1

.. DpddVersionTagEnd

Processing Elements Creating / Updating / Using the Product
______________________________________________________________
.. PECreatorStart

**Creators:**

* LE3_CM_2PCF_WL_ShearShear_Pipeline

**Consumers:**

* WL-SWG

.. PECreatorEnd

Processing Function using the products
________________________________________
.. PFUsingStart

SGS pipeline output product to be used by LE3 and SWGs

.. PFUsingEnd

Proposed for inclusion in EAS/SAS
_________________________________

.. IncludeInSASStart

This product is proposed for inclusion in the SAS: Yes

The covariance matrix gives the error estimates of the shear-shear 2-point correlation function.

.. IncludeInSASEnd

Data Product Elements
________________________
.. DataProductElementsStart

$PrintDataProductElements

.. DataProductElementsEnd

Detailed Description of the Data Product
__________________________________________
.. DetailedDescStart

This product contains the covariance matrix for cosmic shear 2PCF.
This output product is a fits binary table containing important input
parameters as keywords in primary HDU, and a binary table in the next HDU with the
covariance for cosmic shear as described in
 `le3.wl.cm2pcf.output.shearshear2d <https://gitlab.euclid-sgs.uk/ST-DM/ST_FitsDataModel/-/blob/9.2.0/ST_DM_FitsSchema/auxdir/ST_DM_FitsSchema/instances/fit/euc-le3-wl.xml#L664>`_.

Extra metadata associated to the FITS container are the following:

* **SpatialCoverage** a description of the spatial footprint [optional, cot:spatialFootprint],
* **CatalogSelection**: describing the selection in the input catalogues [optional, up to 4 elements]

  *  **CatalogFileName**: the name of the input catalogue [sys:dataFileName]
  *  **Selection**: selection associated to catalogue [string]
  *  **CatalogUse**: for which use case the catalog is employed (=["ShearShear"])
     [string among "PosPos", "PosShear", "ShearShear"]
  *  **CatalogInfo**:  whether position or shear information is used in this catalogue (=["Shear"])
     [string among "Pos", "Shear"]
  * **CatalogOrder**: order associated to catalogue for reporting (e.g. BIN_ID1)[int32]


Keywords
+++++++++++++

This fits table is expected to contain the following keywords in primary HDU,
characterizing the important parameters of the product:

$PrintPrimaryHeader fit/euc-le3-wl.xml le3.wl.cm2pcf.output.shearshear2d

The cosmic shear 2PCF are defined as:

.. math::
    \xi_\pm &=\langle \epsilon_t \epsilon_t\rangle \pm \langle \epsilon_x \epsilon_x\rangle\\
    \xi_x &= \langle  \epsilon_t \epsilon_x \rangle

with :math:`\epsilon_t` tangential component and :math:`\epsilon_x` cross component of ellipticity.

Covariance table
+++++++++++++++++

The table (first HDU, EXTNAME="RS_COVAR_SHEARSHEAR2D") will contain the following columns:

$PrintCatalog fit/euc-le3-wl.xml le3.wl.cm2pcf.output.shearshear2d

.. note::
    Under discussion is the possibility in the future of having as first HDU an
    estimate for Shot Noise :

    #. **THETA_1**: first angular separation (center of spatial bin) [D, float64]
    #. **THETA_2**: second angular separation (center of spatial bin) [D, float64]
    #. **BIN_COMB1**: first index for combination of redshift bins [J, int32]
    #. **BIN_COMB2**: second index for combination of redshift bins [J, int32]
    #. **COV_PP_SH**: covariance between shear-shear :math:`\xi_+` components [D, float64]
    #. **COV_MM_SH**: covariance between shear-shear :math:`\xi_-` components [D, float64]
    #. **COV_PM_SH**: covariance between shear-shear :math:`\xi_+` and :math:`\xi_-` components [D, float64]

.. DetailedDescEnd