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:
|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
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]