The possible role of ground-based support for a better determination of asteroid physical parameters based on Gaia data.

International audienceThe determination of bulk physical properties for the largest possible number of asteroids which will be observed by Gaia is an important task which can be made easier by performing some dedicated groundbased observing campaigns. The proposed actions, consisting of applications of different observing techniques, primarily photometry and polarimetry, are not expected to be triggered by Gaia alarms, nor do they require in principle prompt reaction times triggered by special circumstances. We deal here, conversely, with the problem of improving the amount and quality of data at our disposal concerning some properties of a suitable sample of asteroids, to be used for the purposes of a better calibration of some fundamental relations which are commonly used in asteroid science