IsolatedStarAssociationTask¶

IsolatedStarAssociationTask matches unresolved star sources from the sourceTable_visit datasets into a pure (but not complete) catalog of isolated stars. The output datasets are a catalog of isolated stars (dataset isolated_star_cat) and the associated sources with configured columns from the input catalogs (dataset isolated_star_sources).

Processing summary¶

IsolatedStarAssociationTask reads in all the visit-level source table parquet catalogs in a given tract and matches (associates) the sources together. In particular:

All sourceTable_visit catalogs overlapping a given tract are used as inputs. The configuration variable extra_columns can be used to specify which columns from the inputs are persisted (in addition to the default flux column, input row number, and source id).
Unflagged, unresolved stars above a configured signal-to-noise are selected from each input catalog.
The input stars are associated within a configured match_radius arcseconds. This association is done band-by-band (with the order configured by band_order), and then each band is matched such that all sources are associated with a unique list of stars which cover all the bands in the tract.
The star catalog is matched against itself, and groups of stars that match neighbor(s) within isolation_radius arcseconds are removed from the final isolated star catalog (isolated_star_cat).
All individual sources are associated with the isolated star catalog within match_radius, to create the isolated_star_sources.
The data are collated such that each isolated star has an index to the isolated_star_sources table for quick access of all the individual sources for that star.

Python API summary¶

from lsst.pipe.tasks.isolatedStarAssociation import IsolatedStarAssociationTask

classIsolatedStarAssociationTask(**kwargs): Associate sources into isolated star catalogs...

attributeconfig: Access configuration fields and retargetable subtasks.

methodrun(skymap, tract, source_table_ref_dict): Run the isolated star association task...

Retargetable subtasks¶

source_selector¶

Default

'science'

Field type

Single-selection RegistryField

Choices

'science': lsst.meas.algorithms.sourceSelector.ScienceSourceSelectorTask
'references': lsst.meas.algorithms.sourceSelector.ReferenceSourceSelectorTask
'null': lsst.meas.algorithms.sourceSelector.NullSourceSelectorTask
'objectSize': lsst.meas.algorithms.objectSizeStarSelector.ObjectSizeStarSelectorTask
'flagged': lsst.meas.algorithms.flaggedSourceSelector.FlaggedSourceSelectorTask
'astrometry': lsst.meas.algorithms.astrometrySourceSelector.AstrometrySourceSelectorTask
'matcher': lsst.meas.algorithms.matcherSourceSelector.MatcherSourceSelectorTask

How to select sources. Under normal usage this should not be changed.

Configuration fields¶

band_column¶

Default: 'band'
Field type: str Field

Name of column with band name

band_order¶

Default: ['i', 'z', 'r', 'g', 'y', 'u']
Field type: str ListField

Ordered list of bands to use for matching/storage. Any bands not listed will not be matched.

connections¶

Data type: lsst.pipe.base.config.IsolatedStarAssociationConfigConnections
Field type: ConfigField

Configurations describing the connections of the PipelineTask to datatypes

dec_column¶

Default: 'dec'
Field type: str Field

Name of column with declination.

extra_columns¶

Default: ['x', 'y', 'xErr', 'yErr', 'apFlux_17_0_instFlux', 'apFlux_17_0_instFluxErr', 'apFlux_17_0_flag', 'localBackground_instFlux', 'localBackground_flag', 'ixx', 'iyy', 'ixy']
Field type: str ListField

Extra names of columns to read and persist (beyond instFlux and error).

id_column¶

Default: 'sourceId'
Field type: str Field

Name of column with source id.

inst_flux_field¶

Default: 'apFlux_12_0_instFlux'
Field type: str Field

Full name of instFlux field to use for s/n selection and persistence. The associated flag will be implicity included in bad_flags. Note that this is expected to end in instFlux.

isolation_radius¶

Default: 2.0
Field type: float Field

Isolation radius (arcseconds). Any stars with average centroids within this radius of another star will be rejected from the final catalog. This radius should be at least 2x match_radius.

match_radius¶

Default: 1.0
Field type: float Field

Match radius (arcseconds)

physical_filter_column¶

Default: 'physical_filter'
Field type: str Field

Name of column with physical filter name

ra_column¶

Default: 'ra'
Field type: str Field

Name of column with right ascension.

saveLogOutput¶

Default: True
Field type: bool Field

Flag to enable/disable saving of log output for a task, enabled by default.

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