Stellar variability in low-extinction regions towards the Galactic Bulge

Intensive monitoring of low-extinction windows towards the galactic bulge h as provided in recent years valuable information for studies about the dyna mics, kinematics and formation history of this part of the galaxy mainly by characterizing the bulge stellar populations (Paczynski 1996). Since 1997, we have been conducting an intensive photometric-astrometric survey of the galactic bulge, with the monitoring of about 120000 stars in 12 windows un iformly distributed in galactic latitude and longitude (Blanco & Terndrup 1 989; Blanco 1988) never before submitted to this kind of survey. For this p urpose, we have used the IAG/USP CCD Meridian Circle of the Abrahao de Mora es Observatory. The main objective of this project is the identification an d classification of variable objects. In this work we present the set up an d development of the necessary tools for a project like this and the poster ior analysis of our data. We briefly describe the construction of a program to organize and detect variables among the observed stars, including real time alerts (for variations greater than 0.3 magnitudes). The preliminary a nalysis after the processing of 76 nights of observation yielded 479 variab le stars, from which 96.7% of them are new. We discuss the preliminary clas sification of these variables. based on: a) the observed amplitude of varia tion; b) the shape of light curve; c) the expected variable classes among o ur data and d) the calculated periods, whenever possible. Finally, we discu ss the future perspectives for the project and for the applications and ana lysis of the discovered variable stars.