A model for diffusion-controlled spherical particle growth is presented and solved numerically, showing how, on cooling at sufficient rate from a given fraction solid, growth velocity first increases, and then decreases rapidly when solute fields of adjacent particles overlap. An approximate analytical solution for the spherical particle growth

We report on optical spectroscopy of Swift J1933.9+3258 (=1RXS J193347.6+325422). This X-ray source has recently been classified as a likely radio-quiet AGN on the basis of its broad-band (radio, optical, UV, X-ray) properties (Grupe et al. 2006, ATel #859). In order to confirm its nature, a single 7-min spectrum of the optical counterpart was

We report on the spectroscopic confirmation of four recent optical nova candidates in M31 using the 2.2 m telescope and the Calar Alto Faint Object Spectrograph CAFOS at CAHA on Calar Alto, Spain. The spectra covered the range 400-850 nm (G-200), 490-780 nm (G-100) and 320-580 nm (B-100). The outburst of the apparent nova M31N 2006-06a (RA=00:43:11

Las estructuras de bajo brillo superficial detectadas en las galaxia enanas del Grupo Local y en sus proximidades, son estructuras extendidas que representan un registro fssil del pasado evolutivo de las galaxias. Su composicisn estelar es el objeto de analisis de esta Tesis. En ella se han estudiado dos galaxias de diferente morfologma. La primera

We are currently developing a conceptual design for a future ELT NIR large field of view imager-spectrograph, SMART-MOS, along with several science cases from which top level instrument requirements are being established. This project form part of the EU Framework 6 Joint Research Activity on Smart Focal Planes. The instrument will offer

The Advanced Solar Technology Telescope (ATST) is a 4-m solar telescope being designed for high spatial, spectral and temporal resolution, as well as IR and low-scattered light observations. The overall limit of performance of the telescope is strongly influenced by the qualities of the site at which it is located. Six sites were tested with a