| IGSL source identifiers in original catalogues | 
| Cross-identifications for Initial Gaia Source List sources from the original catalogues from which they were derived. Required constraints: 
 | 
| Name | Type | Length | Unit | Description | Default Value | Unified Content Descriptor | 
|---|---|---|---|---|---|---|
| solution_id | bigint | 8 | Solution identifier | meta.id;meta.version | ||
| source_id | bigint | 8 | Unique source identifier from IGSL2 | meta.id;meta.main | ||
| id_gsc23 | bigint | 8 | Identifier in GSC2.3 | meta.id;meta.dataset | ||
| id_sdss | bigint | 8 | Identifier in SDSS | meta.id;meta.dataset | ||
| id_ucac | int | 4 | Identifier in UCAC | meta.id;meta.dataset | ||
| id_lqrf | int | 4 | Identifier in LQRF | meta.id;meta.dataset | ||
| id_tycho | bigint | 8 | Identifier in Tycho | meta.id;meta.dataset | ||
| id_hip | int | 4 | Identifier in Hipparcos | meta.id;meta.dataset | ||
| id_ppmxl | bigint | 8 | Identifier in PPMXL | meta.id;meta.dataset | ||
| id_ogle | bigint | 8 | Identifier in OGLE | meta.id;meta.dataset | ||
| id_tmass | bigint | 8 | Identifier in 2MASS PSC | meta.id;meta.dataset | ||
| id_epc | varchar | 20 | Identifier in Ecliptic Poles Catalogue | meta.id;meta.dataset | ||
| Total length | 96 |