Data Products Archive

The Ginga data archive at Leicester is currently held in FRF form, and guest investigators visiting Leicester are supported in their analysis of Ginga data on DEC Alpha workstations running OSF. The existing Ginga data analysis software at Leicester has been used to produce a products database of spectra and light curves. Spectra and light curves in several colors are available for each observation. The light curves are at the lowest time resolution for each data mode (e.g. 16s for MPC1 data).

The products have been cleaned and background subtracted. Stringent cleaning criteria and quality control have been applied and a quality assessment has been provided. Background subtraction of Ginga observations is not a trivial process. The LAC had no facility for simultaneous background measurement and backgrounds for source observations have to be reconstructed from contemporaneous blank sky observations or from a more general model. Fluctuations in the diffuse X-ray background can, however, cause significant problems. Wherever possible, the products database provides products produced with the two different methods of background determination to provide the user with an estimate of the importance of these systematic effects.

To ensure maximum utility of the products database, we intend that users will be able to extract spectra from different time intervals. Thus, although access to the raw data will be required to answer detailed questions, the non-expert user, and users requiring answers to basic questions, will not need to go back to the raw data.

The data products have been written in HDS format and have be made available through the Leicester Data Archive Service (LEDAS), which incorporates the HEASARC BROWSE database system. In this way they will be easily accessible over the Internet. The raw FRF data are also held and are also available over the net to expert users.