.. index:: Survey depth; Characterization, Relative photometric accuracy; Characterization
.. _char-survey-sensitivity:
**CHAR-SURV-003:** Sensitivity
==============================
.. include:: definitions.rst
Parent requirement
------------------
Cadence
-------
Once, during PV phase.
Objective
---------
The sensitivity of Euclid is a fundamental quantity for survey planning and exposure scaling, and is directly related to the photometric zeropoints. It is not a top-level scientific requirement, though. A single pass of the EDF-N and - if visible - the EDF-S should suffice.
Observations
------------
Methodology / Uplink procedure
------------------------------
Targets and pointing constraints
--------------------------------
Instrument configuration
------------------------
Inter-operability constraints
-----------------------------
Dependencies
------------
Fulfilling
----------
Fulfilled by
------------
:ref:`calobs-block-pv-survey-validation`
:ref:`calobs-block-f-wide-survey`
Time-critical
-------------
No
Validation
----------
None.
Recovery
--------
None.
In-orbit duration
-----------------
Processing time
---------------
Processing input
----------------
:command:`Ground Processing Input Data`:
:command:`Data Description`:
Data volume
-----------
Processing tools
----------------
Standard wide-survey processing
Processing element
------------------
DataModel:
``_
Quality control parameters
--------------------------
DataModel:
``_
Required accuracy, constraints
------------------------------
Processing method
-----------------
Processing output
-----------------
Determine the number count histograms for each of Euclid's four photometric channels, for point sources in individual images with a :math:`{\rm SNR\ge5}`. The sensitivity is taken as the AB magnitude at which the number counts dropped to 50% of their peak value (effective 50\% completeness limit).
This requires absolute photometric calibration.
Contact person
--------------
Calibration Lead
Status
------
|today| - In progress.
FLAG
----
Priority
--------
Observation record
------------------
Comments
--------
.. raw:: latex
\clearpage