XMM-Newton Users Handbook

A..3.2 Upper Limit Server

The FLIX utility under the link http://www.ledas.ac.uk/flix/flix.html
can be used to check, for a given sky location, whether XMM-Newton has observed that region of the sky and if so, determine XMM-Newton upper limits, X-ray fluxes, and create image cut-outs.

Alternatively, the Database of Upper Limits for slew and pointed observations can be searched from the XSA interface (see Sect. 6.4).

European Space Agency - XMM-Newton Science Operations Centre