OBSERVATION OF MICROLENSING BY AN ASTROMETRIC SATELLITE

E. Høg
Copenhagen University Observatory
Østervoldgade 3, 1350 Copenhagen K, Denmark

Abstract:

The astrometric effect of microlensing will rarely reach a measurable size in observations by GAIA. It is, however, important to do a special effort to detect such rare effects, possibly hidden in the billions of measurements from the satellite since information on the proper motion, distance and mass of deflecting dark bodies might be derived. The satellite would survey these elusive bodies in all directions in the Galaxy, not only in the directions of the LMC or the Galactic bulge where they have hitherto been discovered.
We discuss the possible photometric detection of microlensing events in GAIA observations and the subsequent analysis of the astrometric effect during such events. It seems that measurement of distances, proper motions and masses of MACHOs might be possible. We also discuss the photometric detection of a MACHO passing the face of a star which could be used to determine the proper motion of the MACHO. The discussion concludes that such detections will be rare, but they seem frequent enough to warrant further consideration in connection with GAIA.

Keywords: space astrometry; MACHO; microlensing; ROEMER; GAIA; photometry.
[1] A contribution to Future Possibilities for Astrometry in Space, a workshop at RGO, Cambridge, England, 19-21 June 1995

Erik Hg
Tue Aug 8 06:38:24 MET DST 1995