CalcRhoStatistics¶
- class lsst.analysis.tools.actions.vector.CalcRhoStatistics(*args, **kw)¶
Bases:
KeyedDataActionCalculate rho statistics.
Rho statistics refer to a collection of correlation functions involving PSF ellipticity and size residuals. They quantify the contribution from PSF leakage due to errors in PSF modeling to the weak lensing shear correlation functions.
The exact definitions of rho statistics as defined in [1] are given below.
\[ \begin{align}\begin{aligned}\rho_1(\theta) &= \left\langle \delta e^*_{PSF}(x) \delta e_{PSF}(x+\theta) \right\rangle\\\rho_2(\theta) &= \left\langle e^*_{PSF}(x) \delta e_{PSF}(x+\theta \right\rangle\\\rho_3(\theta) &= \left\langle (e^*_{PSF}\frac{\delta T_{PSF}}{T_{PSF}}(x)) (e_{PSF}\frac{\delta T_{PSF}}{T_{PSF}})(x+\theta) \right\rangle\\\rho_4(\theta) &= \left\langle \delta e^*_{PSF}(x) (e_{PSF}\frac{\delta T_{PSF}}{T_{PSF}})(x+\theta) \right\rangle\\\rho_5(\theta) &= \left\langle e^*_{PSF}(x) (e_{PSF}\frac{\delta T_{PSF}}{T_{PSF}})(x+\theta) \right\rangle\end{aligned}\end{align} \]In addition to these five, we also compute the auto-correlation function of the fractional size residuals and call it as the \(\rho'_3( \theta )\), as referred to in Melchior et al. (2015) [2].
\[\rho'_3(\theta) = \left\langle\frac{\delta T_{PSF}}{T_{PSF}}(x) \frac{\delta T_{PSF}}{T_{PSF}}(x+\theta) \right\rangle\]The definition of ellipticity used in [1] correspond to shear-type, which is typically smaller by a factor of 4 than using distortion-type.
References
[1] (1,2)Jarvis, M., Sheldon, E., Zuntz, J., Kacprzak, T., Bridle, S. L., et. al (2016). The DES Science Verification weak lensing shear catalogues MNRAS, 460, 2245–2281. https://doi.org/10.1093/mnras/stw990; https://arxiv.org/abs/1507.05603
[2]Melchior, P., et. al (2015) Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data MNRAS, 449, no. 3, pp. 2219–2238. https://doi:10.1093/mnras/stv398 https://arxiv.org/abs/1405.4285
Attributes Summary
Dec column (
str, default'coord_dec')The column name to get the PSF xx shape component from.
The column name to get the PSF xy shape component from.
The column name to get the PSF yy shape component from.
RA column (
str, default'coord_ra')The column name to get the xx shape component from.
The column name to get the xy shape component from.
The column name to get the yy shape component from.
The type of ellipticity to calculate (
str, default'distortion')The type of size to calculate (
str, default'trace')TreeCorr configuration (
TreecorrConfig, default<class 'lsst.meas.algorithms.treecorrUtils.TreecorrConfig'>)Methods Summary
__call__(data, **kwargs)Call self as a function.
Return the schema an
AnalysisActionexpects to be present in the arguments supplied to the __call__ method.Subclass hook for computing defaults.
Attributes Documentation
- ellipticityType¶
The type of ellipticity to calculate (
str, default'distortion')Allowed values:
'distortion'Distortion, measured as \((I_{xx}-I_{yy})/(I_{xx}+I_{yy})\)
'shear'Shear, measured as \((I_{xx}-I_{yy})/(I_{xx}+I_{yy}+2\sqrt{I_{xx}I_{yy}-I_{xy}^2})\)
- sizeType¶
The type of size to calculate (
str, default'trace')Allowed values:
'trace'trace radius
'determinant'determinant radius
'None'Field is optional
- treecorr¶
TreeCorr configuration (
TreecorrConfig, default<class 'lsst.meas.algorithms.treecorrUtils.TreecorrConfig'>)
Methods Documentation
- __call__(data: MutableMapping[str, ndarray[Any, dtype[_ScalarType_co]] | Scalar | HealSparseMap | Tensor | Mapping], **kwargs) MutableMapping[str, ndarray[Any, dtype[_ScalarType_co]] | Scalar | HealSparseMap | Tensor | Mapping]¶
Call self as a function.
- getInputSchema() KeyedDataSchema¶
Return the schema an
AnalysisActionexpects to be present in the arguments supplied to the __call__ method.- Returns:
- result
KeyedDataSchema The schema this action requires to be present when calling this action, keys are unformatted.
- result