Shear KSB Calibration

Data product name

sheKsbCalibration

Data product custodian

SHE

Data model tag

8.0

Name of the Schema file

ST_DM_Schema/dictionary/pro/she/euc-test-she.xsd

Schema documentation tag

Documentation for data product element sheKsbCalibration:

This product contains the required calibration data for the KSB shear estimation method.

Documentation for data product element Header:

The generic header of the product.

Data product elements

  • ValidityRange (ins:calibrationValidPeriod)

  • KsbCalibrationFileList (sheKsbCalibrationFileList) [0+ elements]

  • KsbCalibrationFile 1

  • DataStorage (sheKsbCalibrationFile)

  • DataContainer (dss:dataContainer)

  • KsbCalibrationFile 2

  • DataStorage (sheKsbCalibrationFile)

  • DataContainer (dss:dataContainer)

Processing Element(s) creating/using the data product

SHE

Processing function using the data product

SHE

Detailed description of the data product

An XML data product containing calibration data for the KSB shear measurement algorithm. This algorithm requires priors on the unlensed shapes of galaxies in order to properly estimate errors, and so the calibration data is generated by running the KSB algorithm on a reference set of deep images with minimal noise. The resulting shape measurements are stored as the calibration data in a fits table with the following columns:

Parameter name

Fits Data type

Brief description

OBJECT_ID

K

ID of the galaxy in the reference

SHE_KSB_TRAINING_E1

E

Measurement of first component of ellipticity

SHE_KSB_TRAINING_E2

E

Measurement of second component of ellipticity

SHE_KSB_TRAINING_E1_ERR

E

Error on measurement of first component of ellipticity

SHE_KSB_TRAINING_E2_ERR

E

Error on measurement of second component of ellipticity

The distinction we use betwee “Training” and “Calibration” data is that Training data is data which can be obtained prior to any observations from Euclid (e.g. from Euclidized HST images), while Calibration data is obtained and updated throughout the Euclid mission.