In this work, we study the physical and kinematical properties of the emission line region of the Seyfert 1.5 galaxy Mrk 817 using three sets of observations, among which are high-resolution spectra obtained with the Isaac Newton Telescope (INT) on the Canary Islands. We find that, in Mrk 817, the narrow and broad emission lines (NELs and BELs

We study the effects on the leptonic asymmetries A_{FB}, A_{pol} and A_{LR} coming from a model of compositeness. We consider the effects coming from the self-energies and the vertex correction to $Z l^+ l^-$. Thus we use the Altarelli parametrization of the oblique corrections. We get the asymptotic limits of these corrections in terms of the

We report on the a5F-y5Fo multiplet of Ti I and its interest for the study of ``turbulent'' magnetic fields in the quiet solar photosphere. In particular, we argue that the sizable scattering polarization signal of the 4536 Å line (whose lower and upper levels have Landé factors equal to zero), relative to the rest of the lines in the multiplet

Infrared photometry of the WC7-type Wolf-Rayet star WR 125 (MR 93) in 1981-91 shows a 10-fold rise in the 3-4 micron flux during 1990-91. This, together with observations at longer wavelengths, is interpreted in terms of the condensation of dust in its wind, similar to the events observed from episodic dust-making WR stars like WR 48a in 1979-80

Aims.Our aim is to confirm the nature of the long period radial velocity measurements for β Gem first found by Hatzes & Cochran (1993). Methods: .We present precise stellar radial velocity measurements for the K giant star β Gem spanning over 25 years. An examination of the Ca II K emission, spectral line shapes from high resolution data (R = 210

With the goal of confirming the metallicity ``excess'' observed in stars with planetary mass companions, we have conducted a high-precision spectroscopic study of a ``comparison'' sample of dwarfs included in the CORALIE extra-solar planet survey (Santos, Israelian, & Mayor 2001). The targets were chosen following two basic criteria: they make part