This task describes the NICER Space Weather family of modeling tools, available with the NICERDAS analysis system.
The "space weather" model is a background model for NICER data. The model estimates background in a NICER observation by determining the distribution of "space weather" conditions, namely KP index, cut-off rigidity (COR_SAX) and SUN_ANGLE for a given observation, then constructs a background estimate from a background events file (composed of "blank-sky data") by extracting background events that match these conditions.
nispaceweather provides two tools, one to calculate a background spectrum, and one to calculate a background light-curve:
The background events file has been constructed from NICER observations of "blank" fields, i.e.
those with no apparent sources. The fields are named "BKGD_RXTE_N", where N is a number going from 1 to 8. Please note that BKGD_RXTE_7 includes an X-ray source, the star U Cep, and therefore is not
included in the background events file. The background events file is stored in the NICER CALDB
and can be found using this quzcif command:
quzcif nicer xti - - SPACE_WEATHER_BKGLIB now now -