We have extended our evolutionary synthesis models for Star Forming Regions to the γ-ray domain. Applying different yields to the resulting synthetic populations, we obtain lightcurves of γ-ray line emission due to the radioactive decay of stellar nucleosynthesis products, such as 26Al and 60Fe. We present here this time evolution and the

We present results of narrow-band (Hα and adjacent continuum) and broad-band (U, B and V) optical CCD imaging together with high- and intermediate-resolution optical spectroscopy for a sample dwarf and/or irregular Wolf-Rayet (WR) galaxies with absolute B magnitudes in the range -14 to -22 mag, taken from the catalogue of Conti (1991). We find that

We present analytic formulae that approximate the evolution of stars for a wide range of mass M and metallicity Z. Stellar luminosity, radius and core mass are given as a function of age, M and Z, for all phases from the zero-age main sequence up to, and including, the remnant stages. For the most part we find continuous formulae accurate to within

IAUC 7468 available at Central Bureau for Astronomical Telegrams.

CCD UBV photometry of 2279 stars in Sextans A is presented. Differences with the photometric scales of Sandage and Carlson (1985AJ.....90.1019S) and Hoessel et al. (1983ApJ...274..577H) are discussed; recalibration of the Sandage and Carlson data for Cepheids in Sextans A results in a smaller value for the distance modulus, μ=25.6. A similar value

In order to maximize the science return while minimizing running cost, the operational and maintenance requirements are being considered during the design of the GTC. Following this adopted integrated logistic support approach; GTC has produced the baselines of the GTC Operation and Maintenance Plans. These plans describe the science operation