LSSTCam ImSim

The ImSim Schema describes the Science Pipelines outputs for on Imsim simulated full-focal-plane LSSTCam data. It is used in the CI testing of the pipelines.


Parent

Descriptions of the parent objects in the deblending hierarchy.

Indexes
Columns Description Reference Name
objectId Unique index on objectId column idx_Parent_objectId
Column Name Data Type Unit Description UCD Order Principal

DiaObject

The DiaObject table contains descriptions of the astronomical objects detected on one or more difference images.

Column Name Data Type Unit Description UCD Order Principal

DiaSource

Table to store 'difference image sources', sources detected at SNR >=5 on difference images.

Column Name Data Type Unit Description UCD Order Principal

ForcedSource

The forced source table contains forced-photometry source measurement on an individual Exposure based on a Multifit shape model derived from a deep detection.

Column Name Data Type Unit Description UCD Order Principal
detect_isPatchInner boolean True if Object seed is in the inner region of a coadd patch
detect_isPrimary boolean True if Object seed has no children and is in the inner region of a coadd patch and is in the inner region of a coadd tract and is not a sky object
detect_isTractInner boolean True if Object seed is in the inner region of a coadd tract

ForcedSourceOnDiaObject

This is dia_object_forced_source in the Butler repo.

Column Name Data Type Unit Description UCD Order Principal

MatchesObject

Match information for objectTable_tract sources

Column Name Data Type Unit Description UCD Order Principal
index long Incrementing (implicit) row index
match_candidate boolean True for sources that were selected for matching
match_row long Index of matched truth_summary table row, if any
match_id char id of matched truth_summary source, if any
match_truth_type long Type of matched truth_summary source, if any (1/2/3 = galaxy/star/SN)
objectId long objectId of object

MatchesTruth

Match information for truth_summary sources.

Column Name Data Type Unit Description UCD Order Principal
index long Incrementing (implicit) row index
match_candidate boolean True for sources that were selected for matching
match_row long Index of matched objectTable_tract table row, if any
match_count int Number of candidate object matches within match radius
match_chi2 double The chi-squared value of the (best) match
match_n_chi2_finite int The number of finite columns used to compute the match chi2
id char id for truth_summary source.
truth_type long Truth object type (1/2/3 = galaxy/star/SN)
match_objectId long objectId of matched objectTable_tract object, if any

Object

The object table contains descriptions of the multi-epoch static astronomical objects, in particular their astrophysical properties as derived from analysis of the Sources that are associated with them. Note that fast moving objects are kept in the MovingObject tables. Note that less-frequently used columns are stored in a separate table called Object_Extra.

Column Name Data Type Unit Description UCD Order Principal

Source

Table to store high signal-to-noise sources. A source is a measurement of Object's properties from a single image that contains its footprint on the sky.

Column Name Data Type Unit Description UCD Order Principal

Visit

Defines a single Visit.

Column Name Data Type Unit Description UCD Order Principal
decl double deg Deprecated duplicate of dec.
midpoint timestamp Midpoint time for visit at the fiducial center of the focal plane array. TAI, accurate to 10ms.
midpointMjdTai double d Midpoint time for visit at the fiducial center of the focal plane array, expressed as Modified Julian Date, International Atomic Time, accurate to 10ms.
obsStartMjdTai double Start of the visit, expressed as Modified Julian Date, International Atomic Time, accurate to 10ms.

VisitDetector

Defines a single detector of a visit.

Column Name Data Type Unit Description UCD Order Principal
visit long Reference to the corresponding entry in the Visit table.
decl double deg Deprecated duplicate of dec.
midpoint timestamp Midpoint of the visit. TAI, accurate to 10ms.
midpointMjdTai double d Midpoint of the visit, expressed as Modified Julian Date, International Atomic Time, accurate to 10ms.
obsStartMjdTai double Start of the visit, expressed as Modified Julian Date, International Atomic Time, accurate to 10ms.

SDM Schemas is maintained by Rubin Observatory.