Shear Measurements

Data product name

sheMeasurements

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 sheMeasurements:

This product contains the shear measurements made by one or more shear estimation methods.

Documentation for data product element Header:

The generic header of the product.

Data product elements

Base class: cat:observationCatalog

  • BfdMoments (sheBfdMoments) [0-1]

  • DataStorage (sheBfdMomentsFile)

  • DataContainer (dss:dataContainer)

  • Valid (sheValidStatus)

  • KsbShearMeasurements (sheKsbMeasurements) [0-1]

  • DataStorage (sheKsbMeasurementsFile)

  • DataContainer (dss:dataContainer)

  • Valid (sheValidStatus)

  • LensMcShearMeasurements (sheLensMcMeasurements) [0-1]

  • DataStorage (sheLensMcMeasurementsFile)

  • DataContainer (dss:dataContainer)

  • Valid (sheValidStatus)

  • MomentsMlShearMeasurements (sheMomentsMlMeasurements) [0-1]

  • DataStorage (sheMomentsMlMeasurementsFile)

  • DataContainer (dss:dataContainer)

  • Valid (sheValidStatus)

  • RegaussShearMeasurements (sheRegaussMeasurements) [0-1]

  • DataStorage (sheRegaussMeasurementsFile)

  • DataContainer (dss:dataContainer)

  • Valid (sheValidStatus)

  • ObservationDateTime (img:spaceObservationDateTime)

  • ObservationMode (ins:observationMode)

  • NumberExposures (short int)

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 shear measurements fits tables from all three production methods and both control methods. This product will contain the following 5 catalogContainer objects, each pointing to a fits binary table:

  • BfdMoments

  • KsbShearMeasurements

  • LensMcShearMeasurements

  • MomentsMlShearMeasurements

  • RegaussShearMeasurements

All of these are optional, but at least one must exist. In each case, since the storage is a binary table, the table and its header will be stored in the first extension, with the primary HDU being a default, empty image.

Output Catalog

This fits catalogs will contain the following header keywords and columns:

BfdMoments

Header keywords:

Keyword name

Optional?

Brief description

FITS_VER

No

Table format version number

FITS_DEF

No

Table format label

SFLAGVER

No

Flags format version number

EXTNAME

No

HDU label

MHASH

Yes

Model hash of simulations used as input

MSEED

Yes

Model seed of simulations used as input

NSEED

Yes

Noise seed of simulations used as input

WT_N

No

Value of N parameter in weight function

WT_SIGMA

No

Value of sigma parameter in weight function

VALID

No

0: Not tested; 1: Pass; -1: Fail

Columns:

Parameter name

Fits Data type

Brief description

OBJECT_ID

K

Galaxy ID

SHE_BFD_FIT_FLAGS

K

Set of bit flags based on fit status (see ShearMeasurementFlags)

SHE_BFD_VAL_FLAGS

K

Set of bit flags based on validation status (definition TBD)

SHE_BFD_FIT_CLASS

I

Classification of object as galaxy (0), star(1), or unknown (2)

SHE_BFD_UPDATED_RA

D

Estimate of Right Ascension of the galaxy center position [deg]

SHE_BFD_UPDATED_RA_ERR

E

1-Sigma error on RA

SHE_BFD_UPDATED_DEC

D

Estimate of Declination of the galaxy center position [deg]

SHE_BFD_UPDATED_DEC_ERR

E

1-Sigma error on DEC

SHE_BFD_MOMENTS

E7

7 calibrated Fourier Moments

SHE_BFD_PQR

E6

6 terms of calibrated Taylor expanded likelihood

SHE_BFD_COV_EVEN

E15

15 terms of covariance between 5 even calibrated moments

SHE_BFD_COV_ODD

E3

3 terms of covariance between 2 odd calibrated moments

SHE_BFD_WEIGHT*

E

Calibrated weight for this object

SHE_BFD_MOMENTS_UNCAL*

E7

7 uncalibrated Fourier Moments

SHE_BFD_PQR_UNCAL*

E6

6 terms of uncalibrated Taylor expanded likelihood

SHE_BFD_COV_EVEN_UNCAL*

E15

15 terms of covariance between 5 even uncalibrated moments

SHE_BFD_COV_ODD_UNCAL*

E3

3 terms of covariance between 2 odd uncalibrated moments

SHE_WEIGHT_UNCAL*

E

Uncalibrated Weight for this object

Columns marked with * need to be added to the data model.

KsbShearMeasurements

Header keywords:

Keyword name

Optional?

Brief description

FITS_VER

No

Table format version number

FITS_DEF

No

Table format label

SFLAGVER

No

Flags format version number

EXTNAME

No

HDU label

MHASH

Yes

Model hash of simulations used as input

MSEED

Yes

Model seed of simulations used as input

NSEED

Yes

Noise seed of simulations used as input

VALID

No

0: Not tested; 1: Pass; -1: Fail

Columns:

Parameter name

Fits Data type

Brief description

OBJECT_ID

K

Galaxy ID

SHE_KSB_FIT_FLAGS

K

Set of bit flags based on fit status (see ShearMeasurementFlags)

SHE_KSB_VAL_FLAGS

K

Set of bit flags based on validation status (definition TBD)

SHE_KSB_FIT_CLASS

I

Classification of object as galaxy (0), star(1), or unknown (2)

SHE_KSB_G1

E

Calibrated estimate of first component of ellipticity, in (-ra,dec) coordinates

SHE_KSB_G1_ERR

E

Error on G1 in estimating shear

SHE_KSB_G2

E

Calibrated estimate of second component of ellipticity, in (-ra,dec) coordinates

SHE_KSB_G2_ERR

E

Error on G2 in estimating shear

SHE_KSB_G1G2_COVAR

E

Covariance of G1 and G2 in estimating shear

SHE_KSB_WEIGHT

E

Calibrated weight for this object

SHE_KSB_G1_UNCAL

E

Uncalibrated estimate of first component of ellipticity, in (-ra,dec) coordinates

SHE_KSB_G1_UNCAL_ERR

E

Error on G1_UNCAL in estimating shear

SHE_KSB_G2_UNCAL

E

Uncalibrated estimate of second component of ellipticity, in (-ra,dec) coordinates

SHE_KSB_G2_UNCAL_ERR

E

Error on G2_UNCAL in estimating shear

SHE_KSB_G1G2_UNCAL_COVAR

E

Covariance of G1_UNCAL and G2_UNCAL in estimating shear

SHE_KSB_WEIGHT_UNCAL

E

Uncalibrated weight for this object

SHE_KSB_RE

E

Estimate of the size of the galaxy, as scale length for an elliptical profile

SHE_KSB_RE_ERR

E

Error on RE

SHE_KSB_UPDATED_RA

D

Estimate of Right Ascension of the galaxy center position [deg]

SHE_KSB_UPDATED_RA_ERR

E

1-Sigma error on RA

SHE_KSB_UPDATED_DEC

D

Estimate of Declination of the galaxy center position [deg]

SHE_KSB_UPDATED_DEC_ERR

E

1-Sigma error on DEC

SHE_KSB_FLUX

E

Estimate of galaxy flux in ADU

SHE_KSB_FLUX_ERR

E

Error on FLUX

SHE_KSB_SNR

E

Estimate of galaxy signal-to-noise ratio

SHE_KSB_SNR_ERR

E

Error on SNR

LensMcShearMeasurements

Header keywords:

Keyword name

Optional?

Brief description

FITS_VER

No

Table format version number

FITS_DEF

No

Table format label

SFLAGVER

No

Flags format version number

EXTNAME

No

HDU label

MHASH

Yes

Model hash of simulations used as input

MSEED

Yes

Model seed of simulations used as input

NSEED

Yes

Noise seed of simulations used as input

VALID

No

0: Not tested; 1: Pass; -1: Fail

Columns:

Parameter name

Fits Data type

Brief description

OBJECT_ID

K

Galaxy ID

SHE_LENSMC_FIT_FLAGS

K

Set of bit flags based on fit status (see ShearMeasurementFlags)

SHE_LENSMC_VAL_FLAGS

K

Set of bit flags based on validation status (definition TBD)

SHE_LENSMC_FIT_CLASS

I

Classification of object as galaxy (0), star(1), or unknown (2)

SHE_LENSMC_GAL_PVALUE

E

P-value to classify object as a galaxy (p-value < threshold), otherwise as a star; supersedes FIT_CLASS

SHE_LENSMC_G1

E

Calibrated estimate of first component of ellipticity, in (-ra,dec) coords.

SHE_LENSMC_G1_ERR

E

1-Sigma error on G1

SHE_LENSMC_G2

E

Calibrated estimate of second component of ellipticity, in (-ra,dec) coords.

SHE_LENSMC_G2_ERR

E

1-Sigma error on G2

SHE_LENSMC_WEIGHT

E

Calibrated shear weight

SHE_LENSMC_G1_ICAL

E

Internally calibrated estimate of first component of ellipticity, (-ra,dec)

SHE_LENSMC_G1_UNCAL

E

Uncalibrated estimate of first component of ellipticity, in (-ra,dec) coords.

SHE_LENSMC_G1_UNCAL_ERR

E

1-Sigma error on G1_UNCAL or G1_ICAL

SHE_LENSMC_G2_ICAL

E

Internally calibrated estimate of second component of ellipticity, (-ra,dec)

SHE_LENSMC_G2_UNCAL

E

Uncalibrated estimate of second component of ellipticity, in (-ra,dec) coords.

SHE_LENSMC_G2_UNCAL_ERR

E

1-Sigma error on G2_UNCAL or G2_ICAL

SHE_LENSMC_WEIGHT_UNCAL

E

Uncalibrated shear weight

SHE_LENSMC_RA

E

Estimate of Right Ascension of the galaxy center position [deg]

SHE_LENSMC_RA_ERR

E

1-Sigma error on RA

SHE_LENSMC_DEC

E

Estimate of Declination of the galaxy center position [deg]

SHE_LENSMC_DEC_ERR

E

1-Sigma error on DEC

SHE_LENSMC_RE

E

Estimate of the size of the galaxy, as disk scale length [arcsec]

SHE_LENSMC_RE_ERR

E

1-Sigma error on RE

SHE_LENSMC_FLUX

E

Estimate of galaxy flux in ADU per exposure

SHE_LENSMC_FLUX_ERR

E

1-Sigma error on FLUX

SHE_LENSMC_BULGE_FRAC

E

Estimate of galaxy bulge fraction

SHE_LENSMC_BULGE_FRAC_ERR

E

1-Sigma error on BULGE_FRAC

SHE_LENSMC_SNR

E

Estimate of galaxy signal-to-noise ratio

SHE_LENSMC_SNR_ERR

E

1-Sigma error on SNR

SHE_LENSMC_CHI2

E

Goodness of fit reduced chi-squared

SHE_LENSMC_DOF

E

Number of degrees of freedom

SHE_LENSMC_ACCEPTANCE

E

MCMC acceptance rate

SHE_LENSMC_NEXP

E

Number of exposures contributing to the measurements on this object

MomentsMlShearMeasurements

Header keywords:

Keyword name

Optional?

Brief description

FITS_VER

No

Table format version number

FITS_DEF

No

Table format label

SFLAGVER

No

Flags format version number

EXTNAME

No

HDU label

MHASH

Yes

Model hash of simulations used as input

MSEED

Yes

Model seed of simulations used as input

NSEED

Yes

Noise seed of simulations used as input

VALID

No

0: Not tested; 1: Pass; -1: Fail

Columns:

Parameter name

Fits Data type

Brief description

OBJECT_ID

K

Galaxy ID

SHE_MOMENTSML_FIT_FLAGS

K

Set of bit flags based on fit status (see ShearMeasurementFlags)

SHE_MOMENTSML_VAL_FLAGS

K

Set of bit flags based on validation status (definition TBD)

SHE_MOMENTSML_FIT_CLASS

I

Classification of object as galaxy (0), star(1), or unknown (2)

SHE_MOMENTSML_G1

E

Calibrated estimate of first component of shear, in (-ra,dec) coordinates

SHE_MOMENTSML_G1_W

E

Weight for G1 estimate, if separate weights for G1 and G2 are adopted

SHE_MOMENTSML_G2

E

Calibrated estimate of second component of shear, in (-ra,dec) coordinates

SHE_MOMENTSML_G2_W

E

Weight for G2 estimate, if separate weights for G1 and G2 are adopted

SHE_MOMENTSML_WEIGHT

E

Calibrated shear weight

SHE_MOMENTSML_G1_UNCAL

E

Uncalibrated estimate of first component of shear, in (-ra,dec) coordinates

SHE_MOMENTSML_G1_UNCAL_W

E

Uncalibrated weight for G1 estimate

SHE_MOMENTSML_G2_UNCAL

E

Uncalibrated estimate of second component of shear, in (-ra,dec) coordinates

SHE_MOMENTSML_G2_UNCAL_W

E

Uncalibrated weight for G2 estimate

SHE_MOMENTSML_WEIGHT_UNCAL

E

Uncalibrated shear weight

SHE_MOMENTSML_UPDATED_RA

D

Estimate of Right Ascension of the galaxy center position [deg]

SHE_MOMENTSML_UPDATED_RA_ERR

E

1-sigma uncertainty on RA [deg]

SHE_MOMENTSML_UPDATED_DEC

D

Estimate of Declination of the galaxy center position [deg]

SHE_MOMENTSML_UPDATED_DEC_ERR

E

1-sigma uncertainty on DEC [deg]

SHE_MOMENTSML_RE

E

Estimate of galaxy size, as half-light radius [arcsec]

SHE_MOMENTSML_RE_ERR

E

1-sigma uncertainty on RE [arcsec]

SHE_MOMENTSML_FLUX

E

Estimate of galaxy flux in ADU per exposure

SHE_MOMENTSML_SNR

E

Estimate of galaxy signal-to-noise ratio

SHE_MOMENTSML_SERSIC_INDEX

E

Estimate of galaxy Sersic index

SHE_MOMENTSML_NEXP

E

Number of exposures contributing to the measurements on this object

RegaussShearMeasurements

Header keywords:

Keyword name

Optional?

Brief description

FITS_VER

No

Table format version number

FITS_DEF

No

Table format label

SFLAGVER

No

Flags format version number

EXTNAME

No

HDU label

MHASH

Yes

Model hash of simulations used as input

MSEED

Yes

Model seed of simulations used as input

NSEED

Yes

Noise seed of simulations used as input

VALID

No

0: Not tested; 1: Pass; -1: Fail

Columns:

Parameter name

Fits Data type

Brief description

OBJECT_ID

K

Galaxy ID

SHE_REGAUSS_FIT_FLAGS

K

Set of bit flags based on fit status (see ShearMeasurementFlags)

SHE_REGAUSS_VAL_FLAGS

K

Set of bit flags based on validation status (definition TBD)

SHE_REGAUSS_FIT_CLASS

I

Classification of object as galaxy (0), star(1), or unknown (2)

SHE_REGAUSS_G1

E

Calibrated estimate of first component of ellipticity, in (-ra,dec) coordinates

SHE_REGAUSS_G1_ERR

E

Error on G1 in estimating shear

SHE_REGAUSS_G2

E

Calibrated estimate of second component of ellipticity, in (-ra,dec) coordinates

SHE_REGAUSS_G2_ERR

E

Error on G2 in estimating shear

SHE_REGAUSS_G1G2_COVAR

E

Covariance of G1 and G2 in estimating shear

SHE_REGAUSS_WEIGHT

E

Calibrated weight for this object

SHE_REGAUSS_G1_UNCAL

E

Uncalibrated estimate of first component of ellipticity, in (-ra,dec) coordinates

SHE_REGAUSS_G1_UNCAL_ERR

E

Error on G1_UNCAL in estimating shear

SHE_REGAUSS_G2_UNCAL

E

Uncalibrated estimate of second component of ellipticity, in (-ra,dec) coordinates

SHE_REGAUSS_G2_UNCAL_ERR

E

Error on G2_UNCAL in estimating shear

SHE_REGAUSS_G1G2_UNCAL_COVAR

E

Covariance of G1_UNCAL and G2_UNCAL in estimating shear

SHE_REGAUSS_WEIGHT_UNCAL

E

Uncalibrated weight for this object

SHE_REGAUSS_RE

E

Estimate of the size of the galaxy, as scale length for an elliptical profile

SHE_REGAUSS_RE_ERR

E

Error on RE

SHE_REGAUSS_UPDATED_RA

D

Estimate of Right Ascension of the galaxy center position [deg]

SHE_REGAUSS_UPDATED_RA_ERR

E

1-Sigma error on RA

SHE_REGAUSS_UPDATED_DEC

D

Estimate of Declination of the galaxy center position [deg]

SHE_REGAUSS_UPDATED_DEC_ERR

E

1-Sigma error on DEC

SHE_REGAUSS_FLUX

E

Estimate of galaxy flux in ADU

SHE_REGAUSS_FLUX_ERR

E

Error on FLUX

SHE_REGAUSS_SNR

E

Estimate of galaxy signal-to-noise ratio

SHE_REGAUSS_SNR_ERR

E

Error on SNR

ShearMeasurementFlags

The following is a list of flags and their meanings, as will be output in the “FLAGS” column of shear measurements tables:

Bit Value

Name

Critical

Details

2**0

unclassified_failure

Y

Some failure occurred which isn’t described by other flags

2**1

no_data

Y

No image data (including masks, noisemap, etc.) is available for this object in this FoV. Note that such data might be available in another FoV

2**2

no_science_image

Y

The science image(s) is/are missing for this object, but data is otherwise available

2**3

corrupt_science_image

Y

The science image(s) failed sanity checks, or is otherwise suspected to be corrupted

2**4

no_mask

M

The mask(s) is/are missing for this object, but data is otherwise available

2**5

corrupt_mask

M

The mask(s) failed sanity checks, or is otherwise suspected to be corrupted

2**6

no_background_map

M

The background map(s) is/are missing for this object, but data is otherwise available

2**7

corrupt_background_map

M

The background map(s) failed sanity checks, or is otherwise suspected to be corrupted

2**8

no_noisemap

N

The noisemap(s) is/are missing for this object, but data is otherwise available

2**9

corrupt_noisemap

N

The noisemap(s) failed sanity checks, or is otherwise suspected to be corrupted

2**10

no_segmentation_map

M

The segmentation map(s) is/are missing for this object, but data is otherwise available

2**11

corrupt_segmentation_map

M

The segmentation map(s) failed sanity checks, or is otherwise suspected to be corrupted

2**12

insufficient_data

Y

If too many pixels are masked in order to make a reasonable calculation (the most common cases would be if a galaxy is on the edge of the image or in the bleed trail of a star)

2**13

inconsistent_exposures

Y

The exposures are somehow sufficiently inconsistent with each other that they don’t appear to show the same patch of sky

2**14

no_object

Y

If there doesn’t appear to be any object at all at the specified point in the sky, even miscentered.

2**15

not_centered

N

If there is an object in the stamp, but it’s far enough away from the center of the stamp that it’s suspect if it was detected properly

2**16

too_crowded

M

If there are too many objects blended together to make a reliable shape estimate

2**17

low_signal_to_noise

N

If the object is too faint for the method to estimate a shear for it at all

2**18

object_too_small

N

The object is too small to be fit with an adaptive weight function

2**19

object_too_large

N

The object is too large to be fit with an adaptive weight function or to perform other calculations

2**20

no_psf

Y

No PSF image is available for this object

2**22

psf_too_small

Y

The PSF is too small to be fit with an adaptive weight function

2**21

corrupt_psf

Y

The PSF image for this object failed to pass sanity checks, or otherwise appears to be corrupted.

2**23

psf_too_large

Y

The PSF is too large to be fit with an adaptive weight function or to perform other calculations

2**24

too_large_shear

M

The shear value calculated is outside the bounds of (-1,1)

2**25

cannot_correct_distortion

Y

Some error was encountered while attempting to correct for astrometric distortion

2**26

fitting_non_convergence

Y

The fitting procedure for LensMC failed to converge to a solution

2**27

invalid_calculation

Y

Some calculation used invalid input (e.g. attempting to take the square-root of a negative number)

2**29

corrupt_training_data

N

The training data failed sanity checks or is otherwise believed to be corrupted

2**28

no_training_data

N

No training data file is available

2**30

no_calibration_data

M

No calibration data file is available

2**31

corrupt_calibration_data

Y

The calibration data failed sanity checks or is otherwise believed to be corrupted

2**32

bad_calibration

M

The calibration procedure resulted in an invalid shear value

The “Critical” column lists whether this flag indicates a critical failure, or whether it might be possible to nevertheless get some data from the estimate. The value meanings are:

Value

Meaning

Y

“Yes” - Always indicates a critical failure

M

“Maybe” - Under certain circumstances, the data might be usable (for instance, the segmentation map is missing, but LensMC can calculate its own, so it wouldn’t be critical for LensMC)

N

“No” - Any method should be able to recover and produce reliable data, but this does indicate something has gone wrong with input, and the data might be slightly inconsistent with unflagged data. For instance, methods can generally calculate noise from the background map alone, so missing the noisemap is a non-critical failure.