CIRSI Survey of the inner Galactic Bulge Gerry Gilmore, Jacco van Loon, Mark Wilkinson (IoA) ISOGAL Group (IaP Paris, PI Alain Omont; Co-Is GG, Harm Habing, etal) ISOGAL/Scuba Galactic Centre group (MRAO; John Richer, D. Pierce-Price, etal) The central regions of the Milky Way Galaxy are our nearest example of a complex stellar-dynamical system, typical of those which dominate the luminosity of the universe. Description and understanding of the inner galaxy is essential if we are to understand and model similar systems seen only at low resolution and in integrated light at higher redshifts, and earlier times. The Galactic central bulge contains the most extreme stellar cluster known, the majority of the stellar mass of the Galaxy, much of the spiral structure, most of the molecular mass, much of the star formation, all of the disk bar (if it exists), the mysterious central bulge and nucleus, the inner molecular ring, and the greatest number of examples of rare and extreme states of stellar and dynamical evolution. Most of these are confused in projection and obscured. Until recently only low sensitivity and/or low spatial resolution data were available, so that our understanding of the inner Galaxy remains superficial. We have underway a major multi-wavelength study to improve substantially our understanding of this crucial region of the Galaxy. Early DENIS sky survey data at IJK, and complementary UKIRT L data, have been analysed by Unavane, Gilmore etal (MNRAS 295 119 1998;MNRAS 295 145 1998). New L-band data are being obtained in an approved program at the South Pole facility. SCUBA data are being obtained and analysed, together with new high-resolution CO data. A very major ISO survey, ISOGAL (cf Perault etal A+A 315 L165 1996; Omont etal A+A 348 755 1999; Glass etal MNRAS 308 127 1999) has mapped the entire inner bulge (and much of the inner disk). Data reduction for ISOGAL is now complete, and analysis and modelling underway. Extensive follow-up spectroscopy is planned (primarily VLT and 2dF) to map the chemical abundances and kinematics of the inner galaxy. The extant SCUBA data map the ISM, the ISOGAL data quantify the AGB star populations, and the DENIS/South Pole data map the RGB stars, except in regions of high extinction and in the very central few degrees, where serious crowding is an inevitable limitation (the DENIS resolution is 3arcsec) CIRSI H+K mapping of the inner galaxy is now planned, to complement the longer wavelength studies of (primarily) AGB stars, to provide sufficiently large samples of inner bulge RGB stars to allow reliable 3-D spatial analyses, and to map the extinction. An ambition is to use the available study to lead into a significant complementary SIRTF project at longer wavelengths. A large survey is critical, as in any single line of sight foreground and background are inextricably confused unless one can resolve individual sources, and obtain complementary data to identify (statistical) distances. One may quantify the required area, using available dynamical bar models derived from COBE analyses, to show that a region out to 4 degrees from the centre is the minimum requirement (cf figure 15 of Unavane and Gilmore 1998). Since a primary aim is the study of asymmetry, both positive and negative longitudes must be mapped similarly. The required depth and precision is illustrated in fig 23 of Unavane etal 1998, and is one-two percent photometry at K=15, H=17 approximately. Areas of acceptably low extinction can be identified from our ISOGAL data, though there is a strong case to map a contiguous area, for statistical analyses. The resulting colour image of a galactic nucleus will no doubt have many uses, complementing other studies at other wavelengths from the X-ray to the radio.