lsst.meas.algorithms.convertRefcatManager.ConvertGaiaManager Class Reference

Inheritance diagram for lsst.meas.algorithms.convertRefcatManager.ConvertGaiaManager:

Public Member Functions
	__init__ (self, *args, **kwargs)

Public Attributes
	properMotionUnit
	parallaxUnit
	outputUnit

Protected Member Functions
	_getFluxes (self, input)
	_setCoordinateCovariance (self, record, row)

Detailed Description

Special-case convert manager to deal with Gaia fluxes.

Definition at line 464 of file convertRefcatManager.py.

Constructor & Destructor Documentation

__init__()

lsst.meas.algorithms.convertRefcatManager.ConvertGaiaManager.__init__	(		self,
		*	args,
		**	kwargs )

Reimplemented from lsst.meas.algorithms.convertRefcatManager.ConvertRefcatManager.

Definition at line 467 of file convertRefcatManager.py.

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.properMotionUnit = self.config.pm_scale * u.milliarcsecond
        self.parallaxUnit = self.config.parallax_scale * u.milliarcsecond
        self.outputUnit = u.radian * u.radian
 

Member Function Documentation

_getFluxes()

lsst.meas.algorithms.convertRefcatManager.ConvertGaiaManager._getFluxes ( self, inputData )

protected

Compute the flux fields that will go into the output catalog.

Parameters
----------
inputData : `numpy.ndarray`
    The input data to compute fluxes for.

Returns
-------
fluxes : `dict` [`str`, `numpy.ndarray`]
    The values that will go into the flux and fluxErr fields in the
    output catalog.

Reimplemented from lsst.meas.algorithms.convertRefcatManager.ConvertRefcatManager.

Definition at line 473 of file convertRefcatManager.py.

    def _getFluxes(self, input):
        result = {}
 
        def gaiaFluxToFlux(flux, zeroPoint):
            """Equations 5.19 and 5.30 from the Gaia calibration document define the
            conversion from Gaia electron/second fluxes to AB magnitudes.
            https://gea.esac.esa.int/archive/documentation/GDR2/Data_processing/chap_cu5pho/sec_cu5pho_calibr/ssec_cu5pho_calibr_extern.html
            """
            result = ((zeroPoint + -2.5 * np.log10(flux))*u.ABmag).to_value(u.nJy)
            # set 0 instrumental fluxes to 0 (instead of NaN/inf from the math)
            result[flux == 0] = 0
            return result
 
        # Some fluxes are 0, so log10(flux) can give warnings. We handle the
        # zeros explicitly, so they warnings are irrelevant.
        with np.errstate(invalid='ignore', divide='ignore'):
            # The constants below come from table 5.3 in this document;
            # https://gea.esac.esa.int/archive/documentation/GDR2/Data_processing/chap_cu5pho/sec_cu5pho_calibr/ssec_cu5pho_calibr_extern.html
            result['phot_g_mean_flux'] = gaiaFluxToFlux(input['phot_g_mean_flux'], 25.7934)
            result['phot_bp_mean_flux'] = gaiaFluxToFlux(input['phot_bp_mean_flux'], 25.3806)
            result['phot_rp_mean_flux'] = gaiaFluxToFlux(input['phot_rp_mean_flux'], 25.1161)
 
        result['phot_g_mean_fluxErr'] = result['phot_g_mean_flux'] / input['phot_g_mean_flux_over_error']
        result['phot_bp_mean_fluxErr'] = result['phot_bp_mean_flux'] / input['phot_bp_mean_flux_over_error']
        result['phot_rp_mean_fluxErr'] = result['phot_rp_mean_flux'] / input['phot_rp_mean_flux_over_error']
 
        return result
 

_setCoordinateCovariance()

lsst.meas.algorithms.convertRefcatManager.ConvertGaiaManager._setCoordinateCovariance ( self, record, row )

protected

Set the off-diagonal position covariance in a record of an indexed
catalog.

Convert the Gaia coordinate correlations into covariances.

Parameters
----------
record : `lsst.afw.table.SimpleRecord`
    Row from indexed catalog to modify.
row : structured `numpy.array`
    Row from catalog being converted.

Reimplemented from lsst.meas.algorithms.convertRefcatManager.ConvertRefcatManager.

Definition at line 501 of file convertRefcatManager.py.

    def _setCoordinateCovariance(self, record, row):
        """Set the off-diagonal position covariance in a record of an indexed
        catalog.
 
        Convert the Gaia coordinate correlations into covariances.
 
        Parameters
        ----------
        record : `lsst.afw.table.SimpleRecord`
            Row from indexed catalog to modify.
        row : structured `numpy.array`
            Row from catalog being converted.
        """
        inputParams = ['ra', 'dec', 'parallax', 'pmra', 'pmdec']
        outputParams = ['coord_ra', 'coord_dec', 'parallax', 'pm_ra', 'pm_dec']
        # The Gaia standard for naming is to order the parameters as
        # (coordinates, parallax, proper motion), so they need to be reordered
        # as (coordinates, proper motion, parallax) to match the order used
        # in LSST code (i.g. 'coord_parallax_pm_ra_Cov' becomes
        # 'coord_pm_ra_parallax_Cov').
        reorder = [0, 1, 4, 2, 3]
 
        inputUnits = [self.coord_err_unit, self.coord_err_unit, self.parallaxUnit, self.properMotionUnit,
                      self.properMotionUnit]
 
        for i in range(5):
            for j in range(i):
                j_error = row[f'{inputParams[j]}_error'] * inputUnits[j]
                i_error = row[f'{inputParams[i]}_error'] * inputUnits[i]
                ij_corr = row[f'{inputParams[j]}_{inputParams[i]}_corr']
                cov = (i_error * j_error * ij_corr).to_value(self.outputUnit)
 
                # Switch from order of Gaia parallax and proper motion
                # parameters to the desired schema:
                a = (i if (reorder[i] < reorder[j]) else j)
                b = (j if (reorder[i] < reorder[j]) else i)
 
                record.set(self.key_map[f'{outputParams[a]}_{outputParams[b]}_Cov'], cov)
 
 

Member Data Documentation

outputUnit

lsst.meas.algorithms.convertRefcatManager.ConvertGaiaManager.outputUnit

Definition at line 471 of file convertRefcatManager.py.

parallaxUnit

lsst.meas.algorithms.convertRefcatManager.ConvertGaiaManager.parallaxUnit

Definition at line 470 of file convertRefcatManager.py.

properMotionUnit

lsst.meas.algorithms.convertRefcatManager.ConvertGaiaManager.properMotionUnit

Definition at line 469 of file convertRefcatManager.py.

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The documentation for this class was generated from the following file:

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-8.0.0/Linux64/meas_algorithms/ge6526c86ff+3a7c1ac5f1/python/lsst/meas/algorithms/convertRefcatManager.py