Output Product: Tomographic Cosmic Shear Correlation¶

Data Product Name¶

DpdTwoPCFWLShearShear2D

Data Product Custodian¶

WLTWOPCF

Name of the Schema File¶

euc-le3-wl-twopcf-ShearShear2D.xsd

Last Edited for DPDD Version¶

1.1

Processing Elements Creating / Updating / Using the Product¶

Creators:

LE3_2PCF_WL_ShearShear_Pipeline
LE3_CM_2PCF_WL_ShearShear_Pipeline

Consumers:

WL-SWG

Processing Function using the products¶

SGS pipeline output product to be used by LE3 and SWGs

Proposed for inclusion in EAS/SAS¶

This product is proposed for inclusion in the SAS: Yes

Motivation: the product contains the two-point shear-shear tomographic real-space correlation functions requested by the RSD document.

Data Product Elements¶

Header:: object of type sys:genericHeader
Data:: object of type wl2pcf:twoPCFWLShearShear2D
QualityFlags:: object of type dqc:sqfPlaceHolder
Parameters:: object of type ppr:genericKeyValueParameters

Detailed Description of the Data Product¶

This product contains the tomographic cosmic shear 2PCF.

This output product is a fits file (see le3.wl.2pcf.output.shearshear2d in the following FITS descriptors).

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 1 element]
- CatalogFileName: the name of the input catalogue [sys:dataFileName]
- CatalogSHE: type of input catalogue [string among “BFD”, “KSB”, “LensMC”,”MomentsML”,”REGAUSS”,”MER_PHZ”, “OTHER” ]
- 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 [string among “Pos”, “Shear”] (=[“Shear”])
- CatalogOrder: order associated to catalogue for reporting (e.g. BIN_ID1)[int32]

The fits file contains:

a primary array containing important computation parameters as keywords,
binary tables in the next HDUs with cosmic shear 2-PCF for specific redshift bins.

Primary Array¶

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

SIMPLE	/
BITPIX	/
NAXIS	/
EXTEND	/
THMIN	/	Min of angular range
THMAX	/	Max of angular range
OATH	/	Open Angle threshold
THUNIT	/	Unit of theta
BINSCALE	/	lin or log bins
COORDSYS	/	cartesian or spherical
SHE_SOFT	/	Where the input catalogue is coming from (if SHE catalogue used)
SHE_SEL	/	ID of selection made (e.g. tomographic redshifts, stellar mass)
SOFTNAME	/
SOFTVERS	/
END

THMIN: minimal angular value chosen for spatial binning [DoubleKeyword]
THMAX: maximal angular value chosen for spatial binning [DoubleKeyword]
OATH: maximal open angle value used for the approximation [DoubleKeyword]
THUNIT: unit of spatial distance [StringKeyword]
BINSCALE: if linear or logarithmic scales are used for output [StringKeyword]
COORDSYS: if spherical or cartesian computation of distances [StringKeyword]
SHE_SOFT: which SHE catalogue used [StringKeyword]
SHE_SEL: selection for shear catalogue [StringKeyword]
SOFTNAME: name of software used for 2PCF [StringKeyword]
SOFTVERS: version of software used for 2PCF [StringKeyword]

Table (HDU=1…)¶

The following keywords are added to the header of the HDUs:

HDU SHEARSHEAR2D_2PCF_n
Keywords	XTENSION		string
	BITPIX		integer
	NAXIS		integer
	NAXIS1		integer
	NAXIS2		integer
	PCOUNT		integer
	GCOUNT		integer
	TFIELDS		integer
	TTYPE1		string
	TFORM1		string
	TTYPE2		string
	TFORM2		string
	TTYPE3		string
	TFORM3		string
	TTYPE4		string
	TFORM4		string
	TTYPE5		string
	TFORM5		string
	TTYPE6		string
	TFORM6		string
	TTYPE7		string
	TFORM7		string
	TTYPE8		string
	TFORM8		string
	EXTNAME		string
	BIN_ID1	First Bin in Correl	integer
	BIN_ID2	Second Bin in Correl	integer
8 columns table
Columns	THETA		FITS D
	XI_P		FITS D
	XI_M		FITS D
	XI_X		FITS D
	WEIGHT		FITS D
	SQRT_D		FITS D
	SQRT_DCOR		FITS D
	NPAIR		FITS D

BIN_ID1: bin for first catalog [IntegerKeyword]
BIN_ID2: bin for second catalog [IntegerKeyword]
EXTNAME: “SHEARSHEAR2D_2PCF”

and the columns are:

THETA: mean angular separation in the bin [D, float64]
XI_P: cosmic shear 2PCF \xi_+ [D, float64]
XI_M: cosmic shear 2PCF \xi_- [D, float64]
XI_X: cosmic shear 2PCF \xi_x [D, float64]
WEIGHT: total weight for the bin [D, float64]
SQRT_D: Poisson error associated to the bin [D, float64]
SQRT_DCOR: Poisson error associated to the bin, down-weighted by the ratio of number of galaxy pairs by the number of nodes [D, float64].
N_PAIR: Number of pairs [D, float64]

The correlation functions are defined as:

\xi_\pm &=\langle \epsilon_t \epsilon_t\rangle \pm \langle \epsilon_x \epsilon_x\rangle\\ \xi_x &= \langle \epsilon_t \epsilon_x \rangle

with \epsilon_t tangential component and \epsilon_x cross component of ellipticity.

Note

Under discussion is the possibility in the future of having as first HDU a summary table with information on the binning for 2PCF tables (HDU>2):

THETA: angular separation (center of spatial bin) [D, float64]
MIN_THETA: minimal angular separation in the bin [D, float64]
MAX_THETA: maximal angular separation in the bin [D, float64]

and in the second hdu a summary table to allow fast access to the HDU corresponding to a particular bin combination:

BIN_ID1: bin for first catalog [J, int32]
BIN_ID2: bin for second catalog [J, int32]
HDU: HDU index [J, int32]