We present the results of V and I photometries for ~56,500 stars of NGC 3109 obtained from a 467.26(')2 wide-field observations. The internal extinction does not affect the determination of the magnitude of the tip of the red giant branch (TRGB) from which a distance modulus of (m - M)0 = 25.61 ± 0.10 (1.32 ± 0.06 Mpc) have been derived. A mean

The Arcminute Microkelvin Imager is a pair of interferometer arrays operating with six frequency channels spanning 13.9-18.2GHz, for observations on angular scales of 30arcsec-10arcmin and for declinations greater than -15° the Small Array has a sensitivity of 30mJys-1/2 and the Large Array has a sensitivity of 3mJys-1/2. The telescope is aimed

Radiometric data from the Pioneer 10 and 11 spacecrafts have revealed an unexplained constant acceleration of a_A = (8.74+/-1.33)×10^{-10}m s^{-2} towards the Sun, also known as the Pioneer anomaly. Different groups have analyzed the Pioneer data and have got the same results, which rules out computer programming and data handling errors. Attempts

We present here the latest results of the LCID project (Local Cosmology from Isolated Dwarfs), aimed at recovering the full star formation history (SFH) of six isolated dwarf galaxies of the Local Group (LG). Our method of analysis is based on the IAC-pop code, which derives the SFH of a resolved stellar system by comparing the observed and a model

The determination of atmospheric parameters is the first and most fundamental step in the analysis of a stellar spectrum. Current and forthcoming surveys involve samples of up to several million stars, and therefore fully automated approaches are required to handle not just data reduction but also the analysis, and in particular the determination

Dwarf galaxies offer an opportunity to understand the properties of low metallicity star formation both today and at the earliest times at the epoch of the formation of the first stars. Here we concentrate on two galaxies in the Local Group: the dwarf irregular galaxy Leo A, which has been the recent target of deep HST/ACS imaging (Cole et al. 2007