Stellar sources in the ISOGAL intermediate bulge fields

Abstract

We present a study of ISOGAL sources in the "intermediate" galactic bulge (|l| < 2°, |b| ∼ 1°-4°), observed by ISOCAM at 7 and 15 μm. In combination with near-infrared (I, J, Ks) data of DENIS survey, complemented by 2MASS data, we discuss the nature of the ISOGAL sources, their luminosities, the interstellar extinction and the mass-loss rates. A large fraction of the 1464 detected sources at 15 μm are AGB stars above the RGB tip, a number of them show an excess in ([7]-[15])0 and (Ks-[15])0 colours, characteristic of mass-loss. The latter, especially (Ks-[15])0, provide estimates of the mass-loss rates and show their distribution in the range 10-8 to 10-5 M⊙ yr-1.