ISOGAL: A deep survey of the obscured inner Milky Way with ISO at 7 microm and 15 microm and with DENIS in the near-infrared

A. OMONT; G.F. GILMORE; C. ALARD; B. ARACIL; T. AUGUST; K. BALIYAN; S. BEAULIEU; S. BEGON; X. BERTOU,...; (VER PDF PARA LA LISTA COMPLETA)

ASTRONOMY AND ASTROPHYSICS

Año: 2003 vol. 403 p. 975 - 992

0004-6361

The ISOGAL project is an infrared survey of specific regions sampling the Galactic Plane selected to provide information on Galactic structure, stellar populations, stellar mass-loss and the recent star formation history of the inner disk and Bulge of the Galaxy. ISOGAL combines 7 and 15 microm ISOCAM observations – with a resolution of 600 at worst – with DENIS IJKs data to determine the nature of the sources and the interstellar extinction. We have observed about 16 square degrees with a sensitivity approaching 10–20 mJy, detecting 105 sources, mostly AGB stars, red giants and young stars. The main features of the ISOGAL survey and the observations are summarized in this paper, together with a brief discussion of data processing and quality. The primary ISOGAL products are described briefly (a full desciption is given in Schuller et al. 2003): viz. the images and the ISOGAL–DENIS five-wavelength point source catalogue. The main scientific results already derived or in progress are summarized. These include astrometrically calibrated 7 and 15 microm images, determining structures of resolved sources; identification and properties of interstellar dark clouds; quantification of the infrared extinction law and source dereddening; analysis of red giant and (especially) AGB stellar populations in the central Bulge, determining luminosity, presence of circumstellar dust and mass-loss rate, and source classification, supplemented in some cases by ISO/CVF spectroscopy; detection of young stellar objects of diverse types, especially in the inner Bulge with information about the present and recent star formation rate; identification of foreground sources with mid-IR excess. These results are the subject of about 25 refereed papers published or in preparation.