Thermal infrared survey of LMC, SMC and Sagittarius Dwarf Galaxy

The ESO VLT with its suite of infrared instruments (e.g. ISAAC, VISIR) allows for an area-limited deep survey for infrared-bright point sources in nearby local group galaxies. Data in four colours can be collected: 3, 5, 10, and 20mum; the 10/20mum data can be complemented with TIMMI2, a new instrument presently under construction for ESO's 3.6m telescope on La Silla. The scientific result will be a complete catalogue of obscured Asymptotic Giant Branch Stars in the LMC, the SMC and the sagittarius Dwarf Galaxy (SDG). Using mostly twilight time, such a survey can be done for an area of approximate to 100 squarearcmin per year per galaxy. At 10 mum the limiting flux is expected to be 2-3 orders of magnitude fainter than the IRAS point source catalogue. This catalogue would give the first coherent sample of AGB stars with precise distances and consequently absolute bolometric luminosities. It may lead to a substantially better understanding of the mass loss of AGB stars, an important, but as of today largely enigmatic phase of stellar evolution. As a by-product many more IR-bright objects in the Magellanic Clouds, e.g. dust envelopes around normal stars, luminous blue variable stars (LBV) or compact obscured HII-regions, will be discovered. For the SDG no LBVs or YSOs are expected as it had no star formation for the past 5 Gyr.