Data Repositories

As INTEGRAL data are gathered from the satellite, processed, and distributed to the community, they are stored in a number of data repositories. These repositories range from the Primary INTEGRAL Archive Repository residing at ISDC, to the data sets distributed to the General Observers.

Much of the software written for data analysis, as well as operations software designed to run at ISDC, rely on finding data in a pre-determined directory organization regardless of its origin. Thus, all data repositories must be compliant with a common set of organizational rules. Here we are speaking about the intended organization of all repositories used to store INTEGRAL data for use at ISDC or with ISDC-supplied analysis software. Such repositories are said to be ISDC-compliant repositories.

In October 2004, all public INTEGRAL data became available both in the older (revision 1) and in the revised format of the archive (rev. 2). In 2011 another revision of the archive was performed with the same structure as rev. 2. The new ``Archive Revision 3'' format is now the default on the Archive Browse WWW page at:

http://www.isdc.unige.ch/integral/archive#Browse

Current version of the Off-line Scientific Analysis (OSA) is working with any type of data.

The main differences between rev. 1 and the later data format are:

1. a simplified directory and file structure
2. the availability of event time stamps in Julian Dates (JD) instead of On-Board Time (OBT), with corrected energies, standard good time intervals (GTI) and deadtime in the Science Window datasets
3. the adoption of the standard OGIP format for event files making the timing analysis with FTOOLS much easier
4. the correction of all JD time stamps for the offsets between the OBT of each instrument (NB: the OBT values themselves are not corrected)
5. the implementation of some attitude handling optimization

The whole complicated structure of the revision 1 data is shown in Figure 11, and that of the revision 2-3 data in Figure 12. In the following subsections we explain the main branches step by step.

Note that when you start the analysis the only directory which differs from the shown structure is directory obs. This directory is filled in the process of the analysis.

Figure 11: The complete ISDC repository structure of revision 1 data.

Figure 12: The complete ISDC repository structure of revision 2 and 3 data.