In 2007 Yin, Zhang and Tian [1] [Yin et al., 2007] derived the expressions of the refractive indices of biaxial crystals evaluated from the refractive indices ellipsoid equation. In the past we have researched about the simultaneous measurement of birefringence and optical activity in different crystals [2] [Hernández-Rodríguez et al., 2000], [3]

We present deep, intermediate resolution, long-slit Gemini GMOS-S optical spectra of the Sloan Digital Sky Survey (SDSS) type II quasar J002531-104022, which is a highly disturbed system currently undergoing a major merger event. We use these data to model the ages and reddenings of the stellar populations in three distinct spatial regions and find

We use integral field spectroscopy of 13 disc galaxies in the cluster AC114 at z ˜ 0.31 in an attempt to disentangle the physical processes responsible for the transformation of spiral galaxies in clusters. Our sample is selected to display a dominant young stellar population, as indicated by strong Hδ absorption lines in their integrated spectra

We present the first galactic-scale model of the gas dynamics of the prototype barred Seyfert 1 galaxy NGC 1097. We use large-scale FaNTOmM Fabry-Perot interferometric data covering the entire galactic disc and combine the distribution and kinematics maps with high-resolution two-dimensional spectroscopy from the Gemini telescope. We build a

Context. The current generation of X-ray satellites has discovered many new X-ray sources that are difficult to classify within the well-described subclasses. The hard X-ray source IGR J11215-5952 is a peculiar transient, displaying very short X-ray outbursts every 165 days. Aims: To characterise the source, we obtained high-resolution spectra of

Context. Resonance rings and pseudorings (here collectively called rings) are thought to be related to the gathering of material near dynamical resonances caused by non-axisymmetries in galaxy discs. This means that they are the result of secular evolution processes that redistribute material and angular momentum in discs. Studying them may give