Published online by Cambridge University Press: 15 February 2011
The Gaia pixel-level data simulator GIBIS (Gaia Instrument and Basic Image Simulator,Babusiaux (2005)) provides detailed artificial data for all three instruments on-board theGaia spacecraft. This data is used for the preparation of procedures required for theanalysis of real Gaia data to come during the mission. Among the effects that stronglyaffect all Gaia data, that therefore have to be modelled with GIBIS, is charge transferinefficiency (CTI). CTI, caused by radiation-induced microscopic defects in the CCDdetectors, becomes manifest in a distortion of the line spread functions of observedobjects, as well as in a loss of photo-generated charges inside the window allocated toeach observed source. It affects the astrometric, photometric, and spectroscopic accuracyof the data. The CTI effects on a particular observation depend on observations donebefore, on CCD operations such as gate activity and charge injections, and on physicaleffects such as the sky background brightness and cosmic ray events in the detectors. Inthis paper, an approach for the simulation of CTI with GIBIS is presented and theinfluence of the sky background brightness and cosmic ray events of CTI is discussed inmore detail.