Data formats and data reduction software

The raw telemetry data, consisting of housekeeping and scientific data, are stored, processed and checked by the SOC, made available to Quick Look Analysis (QLA) and temporarily archived per orbit (last 10 orbits on-line). After that, SOC organizes telemetry data in Observing Periods (OP), covering several orbits, and archives them as FOT, together with auxiliary data such as On-Board Time(OBT)/Universal Time(UT) conversion, reconstructed attitude, satellite ephemeris, experiment configuration. Raw-data decompression and reduction to formats suitable for data analysis is possible by means of specific softwares (in the case of PDS/GRBM the raw data pre-processing software was developed ad hoc by the hardware team, as described in section 4.10).

The software for BeppoSAX data reduction has been developed in two different environments:

• XAS (X-ray Astronomy Analysis System, ([Chiappetti and Dal Fiume 1997]), specifically for the PDS, HPGSPC and MECS instruments. XAS software was developed mainly in FORTRAN language, with some modules in C, and is maintained at IFCTR/CNR (Milan), ITESRE/CNR (Bologna), and SDC. In this environment all files are in ASCII or specific XAS format. Programs are available to convert these files to FITS/OGIP format, for data analysis with standard packages like XSPEC, XRONOS, XIMAGE, etc. The dialog with the programs is through run-string and/or environmental variables. The software can operate both on the pre-processed raw data and the FOT data. XAS software is available for DEC Ultrix 4.3, DEC Unix 3.2, HP-UX 9.01/9.05 and SUN Os 4.1.x operating systems. As a XAS contributed software, a sophisticated IDL (Interactive Digital Language) program has been developed at ITESRE/CNR for XAS data analysis and plotting (see section 4.10).
• FTOOLS, initially for the LECS, MECS and WFC instruments but now also for PDS and HPGSPC. The NFI softwares are part of the same package, SAXDAS, and share a number of programs. This software was adapted from existing programs developed for other missions and is maintained by SSD/ESA, SAX/SDC and IAS/CNR. SAXDAS software is available for Alpha OSF-1, SUN OS 4.1.x, HP-UX operating systems. The WFC software constitutes a different package and was developed at SRU/SRON. In this environment all files that are newly created by any of the software moduli ([Jager et al. 1997,in 't Zand 1992]) are exclusively in FITS format (OGIP compatible). The dialog with the programs is through run-string and parameter files.

We will go in some more detail with the PDS/GRBM specific data reduction and analysis tools in chapter 4, where we outline GRBM data analysis techniques.