Asymptotic giant branch stars in the ISOGAL survey

Abstract

We present and analyse the data of a field at 1 = 0°, b = +1° from the ISOGAL survey of selected areas of the inner Galactic bulge at 15 and 7 μm. In combination with IJK_s data from the near-infrared southern sky survey DENIS, the ISOCAM data allow the first detailed study of infrared stellar populations in very obscured regions of the inner Galaxy. The K/J-K magnitude-color diagram for the sources detected in the ISOGAL field shows a remarkably well-defined tip of the bulge red giant sequence. A few stars clearly show an excess in the value of J-K with respect to the red giant sequence. Most of them are probably AGB stars with large mass-loss rates. The other color-color and magnitude-color diagrams are also discussed. About half of the source have observed K-[15] colors. Thus these data suggest that these are masslosing stars.