Appendix 6. Merged Working Database Source Information

3. Merged Database Table Formats

c. Merged Source Cross-Reference (Link) Tables

The following table contains brief descriptions of the entries in the Survey, 6x and Calibration Merged Source Cross-Reference Tables. The Cross-Reference Tables for the Merged Point and Extended Sources have the same format.

The Cross-Reference tables contain information linking each merged group with its individual extractions in the respective WDB. The tables contain one row for each WDB extraction that has been associated with a merged source group. Each row in the tables contains the unique merged group identifier (gcntr), the unique WDB identifier (cntr/pts_key for Point Source WDBs and cntr/ext_key for Extended Source WDBs) and the number of groups with which that WDB extraction has been associated (ngrp). A WDB extraction may be associated with more than one merged group in confused situations. The cntr/pts_key/ext_key values for such WDB extractions will appear more than once in the Cross-Reference Tables, accompanied by the gcntr of each of the groups to which it has been associated.

Searching this table for all entries with a particular value of gcntr returns the identifiers of all WDB entries in a particular merged group. Alternately, searching this table for a particular value of cntr/pts_key/ext_key returns a list of all groups to which a particular WDB extraction belongs.

The order of the entries in this table is the same as that presented in the IRSA/GATOR query page for these tables.

The columns in the following table are:

Column NameFormatUnitsnullsDescription
gcntr %10d---no Unique identifier of the merged group within a given database. This value is set to be the cntr/pts_key value of the "seed" extraction for the group (see A6.2).

Gcntr is not unique within a Cross-Reference Table. There are as many entries with the same value of gcntr as there are extractions in the group (napp).

The gcntr identifier is cross-referenced in the individual WDBs and the Merged Source Information Tables (VI.4.a and VI.4.b).

Note: Gcntr is unique only within a given database. Sources in the Merged Survey, 6x and Calibration Tables with the same gcntr identifiers are not the same object on the sky.

cntr/pts_key or cntr/ext_key %10d---no Unique identifier of the extraction in the respective Point or Extended Source WDB that is associated with the group identified by gcntr. Cntr is not necessarily unique within the Cross-Reference table because an extraction may be associated with more than one merged group in confused situations.
ngrp %3d---no Number of merged groups in which this extraction is found.
ngrp > 1 indicates confusion.

[Last Updated: 2006 September 28; by S. Wheelock & R. Cutri]

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