Stellar sources in the ISOGAL intermediate bulge fields ^*,**,***

¹ Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
² Institut d'Astrophysique de Paris, CNRS, 98bis Bld. Arago, 75014 Paris, France e-mail: omont@iap.fr
³ GEPI, Observatoire de Paris, 61 Av. de l'Observatoire, 75014, Paris, France
⁴ Physical Research Laboratory, Navarangpura, Ahmedabad 380009, India

Corresponding author: D. K. Ojha, ojha@tifr.res.in

Received: 3 June 2002
Accepted: 11 February 2003

Abstract

We present a study of ISOGAL sources in the “intermediate” galactic bulge (, –4°), observed by ISOCAM at 7 and 15 μm. In combination with near-infrared (I, J, K_s) 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 (K_s–[15])₀ colours, characteristic of mass-loss. The latter, especially (K_s–[15])₀, provide estimates of the mass-loss rates and show their distribution in the range 10^-8 to 10 yr^-1.