UAT

class pyvo.registry.UAT(uat_keyword, *, expand_up=0, expand_down=0)[source]

Bases: SubqueriedConstraint

A constraint selecting resources having UAT keywords as subjects.

The UAT (Unified Astronomy Thesaurus) is a hierarchical system of concepts in astronomy. In the VO, its concept identifiers are dashed strings, something like x-ray-transient-sources. The full list of identifiers is available from http://www.ivoa.net/rdf/uat.

Note that not all data providers properly use UAT keywords in their subjects even in 2025 (they should, though), and their keyword assignments may not always be optimal. Consider doing free text searches if UAT-based results are disappointing, and then telling the respective data providers about missing keywords.

Parameters:
uat_keyword: str

An identifier from http://www.ivoa.net/rdf/uat, i.e., a string like type-ib-supernovae. Note that these are always all-lowercase.

expand_up: int

In addition to the concept itself, also include expand_up levels of parent concepts (this is probably rarely makes sense beyond 1).

expand_down: int

In addition to the concept itself, also include expand_down levels of more specialised concepts (this is usually a good idea; having more than 10 here for now is equivalent to infinity).