At this website it is possible to filter X-ray sources on the catalog and diagrams pages using simple boolean expressions query language which mimics syntax of WHERE clause in SQL language. One can also download query result from the catalog page in machine-readable format by clicking one of the Download links on the top right after applying desired filter.The language consists of arbitrary number of expressions combined together using AND or OR clauses. Expression usually has the following structure (square brackets mean optional clauses):
parameter operator value [AND | OR [NOT] expression] [, …]
where parameter is the name of any X-ray source catalog property present in the database. There is no unit specification so the actual query compares the data with user input value in the default database units.
Query examples
M82 – select sources in 1 arcmin vicinity of M82 center
cone('M31', '1deg') AND sc_det_ml < 100 – select faint X-ray sources not further than 1 degree from M31 center
is_ulx = true AND n_detections > 2 – select ULXs which were detected more than once
iauname IN {"3XMM J053406.7+220337", "3XMM J053406.6+220438"} – select specific sources by their IAU names
srcid IN {3, 4} – select specific sources by their source IDs (useful for larger subsets)