Data-reduction software for GIRAFFE, the VLT medium-resolution multi-object fiber-fed spectrograph

A brief overview is given of the data-reduction software (DRS) being developed at Geneva and Paris Observatories for the fiber-fed multi-object GIRAFFE spectrograph - part of the VLT FLAMES facility. The specific aspects of each of three modes is presented and discussed. The localization and the extraction are described in more details, the original features are outlined and the critical issue addressed. We discuss the problem of the PSF variation across the surface of the detector and the impact on the sky subtraction. The strategy of the real-time data quality assessment using the simultaneous calibration exposure is described. Some aspect of the DRS implementation and the VLT environment are discussed. The dirty prototype of the DRS under Matlab including the crude instrument simulator is discussed and some experiments measuring the expected accuracy of radial- velocity are shown.