A method for studying the star formation history (SFH) of nearby galaxies, as a function of time, has been developped and implemented. For the first time, the full SFH of a nearby dwarf irregular galaxy (DIG) has been retrieved from the photometry of its resolved stars. In the [(V-I),I] colour-magnitude diagram (CMD) of about 18000 stars in NGC

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We present observations at 10 and 15 GHz taken with the Tenerife experiments in a band of the sky at declination +35 deg. These experiments are sensitive to multipoles in the range l = 10--30. The sensitivities per beam are 56 and 20 mu K for the 10 and 15 GHz data, respectively. After subtraction of the prediction of known radio sources, the

We report CGRO, RXTE, ASCA, ROSAT, IUE, HST and ground-based observations of a large flare in 3C 279 in February 1996. X-rays and γ-rays peaked simultaneously (within one day). We show simultaneous spectral energy distributions prior to and near the flare peak. The γ-ray flare was the brightest ever observed in this source.

Since its discovery in 1992, the superluminal X-ray transient GRS 1915+105 has been extensively observed in an attempt to understand its behaviour. We present here preliminary results from a multi-wavelength campaign undertaken from July to September 1996. This study includes X-ray data from the RXTE All Sky Monitor and BATSE, two-frequency data

In this Letter, we show that the optically bright stars above the tip of the first red giant branch (TRGB) in the color-magnitude diagrams (CMDs) of nearby dwarf elliptical (dE) galaxies, commonly interpreted as indication of the existence of an intermediate-age population, may be, in certain circumstances, an artifact of observational effects on a