Observations of cold gas in the inner galactic disk show a clumpy, highly asymmetric distribution, with large non-circular velocities. Recent work has shown that the flow of gas in the inner few kpc is dominated by a rapidly rotating bar, with corotation at R ≃ 2.4 kpc and oriented at an angle of θincl = 16 ± 2° with the line-of-sight to the Galactic Center. From the kinematical model the gravitational potential in the inner Galaxy can be determined. Gas falls inwards through the bar's inner Lindblad resonance at a rate of ∼ 0.1M⊙/ yr; this suggests that in episodic star formation significant mass and angular momentum may be added to the inner bulge.

The propagation of cosmic ray protons and anti–protons from the inner Galaxy via the galactic halo to the Sun supplies a good agreement with the observed cosmic ray gradient and is in the order of the measured anti-proton flux. Ultra heavy cosmic ray nuclei may have the same origin.

Recent IRAS surveys have revealed that large infrared luminosities are originated from active star forming regions in galaxies (Soifer et al. 1986). Such starburst regions are frequently located in galactic central regions and CO observations indicate that these regions contain a large amount of molecular gas (e.g. Ishizuki et al. 1990). However, the triggering mechanism for starbursts and the mechanism of the high mass supply rate of gas into a galactic center are still unclear.

We use information contained in CMDs of metal-rich globular clusters, in order to compute a grid synthetic spectra for 10 evolutionary stages. These synthetic spectra are added up to reproduce the composite spectra of S0/E galaxies.

This is a status report on a continuing program using the Hubble Space Telescope (HST) Wide–Field Camera (WFC) to probe the stellar population of the Galactic bulge to fainter magnitudes. We seek the mean age of the stars and the initial mass function (IMF). Galactic bulge stars offer the only opportunity to investigate the IMF of a super metal–rich population. They are 100 times closer than the next nearest sample.

We study two different samples of long-period variable Asymptotic Giant Branch (AGB) stars in a field of low and homogeneous extinction towards the Galactic bulge, the Palomar-Groningen field Nr. 3. The samples were selected to study the evolution of the late phases on the AGB. One sample consists of 486 variables (mostly Miras) optically detected and studied by Plaut (1971) and by Wesselink (1987). The other sample is selected from the IRAS Point Source Catalogue and consists of 239 sources. We made additional infrared measurements between 1.2 and 13 μm for a large fraction of both samples. This information was used to identify the IRAS sources and derive the apparent bolometric magnitudes. The samples of Miras and variable IRAS sources have a similar apparent bolometric magnitude distributions, but are displaced by an amount significantly less than expected from the Mira period-luminosity relation (Feast et al. 1989; 0.3 magnitudes as opposed to 0.6 magnitudes). The surface density distribution along the minor axis of the bulge is the same for both samples. We conclude that both samples have evolved from the same parent population and that they represent different evolutionary stages on the AGB. The IRAS sources with the longer periods (on average 450 days (Whitelock et al. 1991) versus on average 250 days for the optical sample) are the further evolved objects. As the IRAS sources have higher mass loss rates we conclude that mass loss increases during the late stages of the evolution. However, we find indications that in some stars the mass loss process has been interrupted for some time; mass loss could be an intermittent process although its overall rate increases in time.

We present the first results of the Two-Micron Galactic Survey (TMGS). The sources are concentrated on the Galactic plane, the width of the distribution increasing between 0° and 30° longitude. Several obscuration lanes are seen, showing that K-band absorption can be high and patchy.

Low resolution spectra of two stars of the Baade Window were obtained with the 1.5m telescope at ESO. Their temperatures and gravities are obtained by using their location in colour magnitude diagrams of bulge clusters, and through synthetic spectra fitting, their metallicities are derived.

Kinematics and abundances have been determined for a large sample of K giants in a field at ∼2 kpc from the center to study the relationship between the bulge and the halo. There are two different kinematic groups evident. The metal-poor stars have low rotation and high velocity dispersion, and so can be associated with the halo. The metal-richer stars have intermediate rotation. Our data suggest that the bulge and halo could be separate kinematical entities.

Classification algorithms based on neural network techniques are applied to study if the bulge stars can be differentiated from other stars belonging to other Galactic components. A synthetic sample is build as a mixture of four components, thin disk, thick disk, halo and bulge, according to some stellar system models and considering observational errors.

The Baade's Window bulge is a metal-rich, rotationally supported entity, whereas the solar neighbourhood halo is metal-poor and non-rotating; what is the connection between these two spheroid components?

We present results of a spectroscopic survey of 847 K-giants from 3 low absorption windows at (5,-12), (-5,-12) and (-25,-12). This is a seven times larger sample than has been previously studied in this region.

SiO maser emission from the Bulge IRAS sources has been searched by the v=1, J=1−0 and v=2, J=1—0 transitions to investigate the kinematics of the Galactic Bulge, resulting in a sample of 124 line-of-sight velocities. The rotation velocity, velocity dispersion, and velocity offset at l = 0° for the sample are found to be , and —18.2±9.7 km s−1, respectively (80% confidence interval). Furthermore we find trends for the rotation velocity and velocity dispersion to decrease with distance from the galactic plane. These trends are supported by a larger sample constructed by incorporating other available velocity data on the Bulge IRAS sources. The rotation velocity and velocity dispersion are expressed as 15.6—1.23x|b(deg)| km s−1 deg−1 and 101−3.6x |b(deg)| km s−1, respectively. The implications of the observed quantities are discussed.

The Two Micron Galactic Survey (TMGS) is described by Calbet et al. (this symposium) and Mahoney et al. (1990). It has been cross-correlated with the IRAS point source catalogue (IRPS) using a 15-arcsec search radius, and preliminary results are presented here.

We describe an ongoing survey to search for dark matter via lensing events of stars in the Galactic Bulge. The principal properties of the survey are described, and some preliminary results are shown for newly-discovered variables. We discuss some of the projects related to the study of the Galactic Bulge that can be addressed using these data, and describe the future plans for the survey over the coming few years.

TiO bands at λ 620 nm are synthesized. The behaviour of these bands as a function of stellar parameters is studied. Application to composite spectra of one galactic bulge globular cluster and to bulges of elliptical galaxies is also carried out. TiO bands may be useful metallicity indicators.

We investigate the shape of the velocity ellipsoid in the Galactic bulge by combining radial velocities and proper motions. We find that the velocity ellipsoid is nearly isotropic.

Kinematics and abundances of samples of K and M giants in a field at the edge of the bulge are compared. Despite a higher mean abundance, the M giants have the same kinematics as the metal-richer K giants.

Preliminary results are shown of our study on the metallicities and ages of the stellar populations present in different components along the line of sight to field #3 of the Palomar-Groningen Variable Star Survey (PG3) with synthetic Hertzsprung-Russell Diagrams (HRDs).

We have obtained CCD BVRI colour-magnitude diagrams for a series of disk globular clusters, improving parameters and detecting a new one: Lyngå 7. Using the magnitude difference between turn-off and horizontal branch Δ(TO-HB) as an age discriminator, and their spatial distribution we compare old disk open clusters, young halo globular clusters, and metal-rich disk globular clusters, obtaining clues to the Galaxy formation process.

Using a model of population synthesis well tuned to reproduce the disc and halo populations of the Galaxy, we show how to set constrains on the bulge population parameters using magnitude and colour distribution in 4 directions near the bulge. This first analysis result in a bulge with a disc-like LF but a density law much steeper in the center.