XMM-Newton Science Analysis System


catprep (catprep-0.5.7) [xmmsas_20230412_1735-21.0.0]

Reference catalogues

• USNO-B1: the US Naval Observatory catalog contains just over one billion objects from measurements of Schmidt plates taken at various observatories over the past 50 years. It covers the entire sky.

• 2MASS: the Two Micron All Sky Survey, conducted by CalTech using telescopes in Arizona and Chile. The catalogue covers the entire sky, and contains about 600 million objects with a typical positional accuracy of 0.5 arc-seconds. The main value of 2MASS in this context is at very low galactic latitudes.

• SDSS: the Sloan Digital Sky survey data release 8 - positions extracted from the photoPrimary table to a set of text files at Leicester using SQL scripts. This has the deepest sky coverage but only about one third of the sky is covered. When an XMM field is covered by SDSS, its goodness of fit value is almost always the largest.

The paths to these three reference catalogues have now to be set in the following three environment variables

• UB1_PATH for the USNO catalog
• TWOMASS_PATH for the 2MASS catalog
• SDSS_PATH for the Sloan catalog.

An additional test script /test/test_cat_access.csh is now added, which sets these three environment variables to the cat_data subdirectory of /test/. The small set of files tested by the input file P0005010301EPX000OBSMLI0000.fits have been put in this subdirectory. A more extensive test would involve changing these environment variables to paths depending on the local software environment.