We present an analysis of radii of giant stars with 6200 K>= T_eff >= 3800 K based on angular diameters obtained by means of the IRFM and distances computed from Hipparcos parallaxes. In order to asses the reliability of IRFM diameters we have considered a selected sample of stars whose diameters have been directly measured by interferometric

We present new long-slit William Herschel Telescope spectroscopic observations of the lens galaxy G1 associated with the double-imaged QSO 0957+561A,B. The central stellar velocity dispersion obtained, σl=310+/-20 km s-1, is in reasonable agreement with other measurements of this dynamical parameter. Using all updated measurements of the stellar

We present the first spectropolarimetric observations of the symbiotic nova HM Sge. We first note that marked spectral changes occurred: in the near IR the spectrum of the Mira in the system has clearly appeared. The nebular emission line spectrum remains largely unchanged but we detect for the first time the Raman line at lambda 6825. These

The Infrared Space Observatory (ISO) coronal line spectrum of the brightest Seyfert galaxies from the CfA sample is presented and modeled. ISO observations of [O IV] 25.9 μm, [Ne V] 14.3 μm, [Mg VIII] 3.02 μm, and [Si IX] 2.58 μm lines are presented; their relationship with the soft part of the ionizing spectrum from 50 to 300 eV is investigated

We present synthetic optical spectra in the red and far-red (640-930 nm) of a sample of field L dwarfs suitably selected to cover this new spectral class, and the brown dwarf GL 229B. We have used the recent ``dusty'' atmospheres by Tsuji (cite{tsuji00}) and by Allard (cite{allard99}), and a synthesis code (Pavlenko et al. cite{pav95}) working

On March 2 06:00 UT the transient source XTE J1859+226 had faded considerably to R=18.0 in the optical (IAC) and to a flux of about 13 mCrab (RXTE ASM). However, it clearly remains active in the X-rays. From extrapolating the last spectrum obtained with HST on 2000, February 8th we predict the following approximate magnitude and colours: V~18.4, U