.. _NIRAbsPhotoCalibration:

[to complete] NIR Absolute Photometric Calibration Factors
==============================================================

$SetSchemaPath nir/euc-test-nir-RelPhotoDetCalibration.xsd

Data Product Name
__________________
.. DataProductNameStart

$PrintDataProductName

.. DataProductNameEnd

Data Product Custodian
_________________________________
.. DataProductCustodianStart

$PrintDataProductCustodian

.. DataProductCustodianEnd

Name of the Schema File
________________________
.. NameSchemaStart

$PrintSchemaFilename

.. NameSchemaEnd

Data Product Elements
______________________
.. DataProductElementsStart

$PrintDataProductElements

.. DataProductElementsEnd


Detailed Description of the Data Product
_________________________________________
.. DetailedDescStart

The **DpdNirAbsPhotoCalibration** data contains absolute photometric calibration parameters, to convert input data
to physical units.

This is a "pure" xml Data Product that contains the inverse sensitivity value.

A DpdNirAbsPhotoCalibration for each filter is foreseen.

It is structured with a set of metadata to define absolute photometric parameters and validity range.


Processing Element(s) creating/using the data product
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. PECreatorStart

The **DpdNirAbsPhotoCalibration** is created by the *NIR_AbsolutePhotometry_Pipeline*.

This pipeline compares "white dwarf" fluxes, extracted in dedicated observations, to derive an inverse sensitivity constant,
which can be used to convert from electrons per second (e/s) to microJanskys (μJy). In addition to computing the inverse
sensitivity, zero points for converting to AB magnitude and Vega magnitude are provided (ZPAB and ZPVEGA, respectively).
Uncertainties are reported for all quantities.

The task responsible for the DpdNirAbsPhotoCalibration creation is **NIR_ComputeAbsolutePhotometry** (under
*NIR_AbsolutePhotometry* project).

.. PECreatorEnd


Processing function using the data product
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. PFUsingStart

This is an internal NIR data product, and it is used only by the NIR PF.

It is applied by the **NIR_ApplyAbsolutePhotometry** task (under *NIR_AbsolutePhotometry* project) inside the *NIR_ProcessField_Pipeline*.


The task writes the  inverse sensitivity constant on *PHOTFNU* keyword. In combination with relative photometric keywords
it can be used to convert from native image units to absolute flux, in μJy.

      flux_in_microJy =  PHOTFNU x PHRELEX x PHRELDT x pixel_value

.. PFUsingEnd

Data Product structure description
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. DataProductDescrStart

The main elements inside the *Data* section are:

* **Filter**: The filter name (e.g. NIR_Y, NIR_J, NIR_H)
* **ValidityRange**: Calibration file validity period estimated
* **StandardStar**: Name of Standard Star used for calibration
* **CalibrationWavelength**: Calibration Wavelength
* **CentralWavelength**: Central Wavelength
* **HalfPowerBandwidth**: Half Power Bandwidth
* **InverseSensitivity**: Inverse Sensitivity
* **VegaMagnitude**: Vega Magnitude

.. DataProductDescrEnd

.. DetailedDescEnd