We present the optical effects of different tests that simulate the aerospace environment on the liquid-crystal variable retarders (LCVRs) used in the Imaging Magnetograph eXperiment postfocal instrument of the SUNRISE payload within the NASA Long Duration Balloon program. Analysis of the influence of vacuum, temperature, vibration, and gamma and

Globular clusters (GCs) play an essential role in understanding the star formation history of galaxies. At the same time GCs are the best candidates to check the reliability of single stellar population (SSP) models which have broad ranging applications. On the basis of a new empirical stellar library in the K band, new SSP model predictions

Near-Infrared JHKL photometry of the symbiotic star Hen 2-147 between 1981 and 2005, monitored from the South African Astronomical Observatory (SAAO) at Sutherland. All but one observations were made on the 0.75m telescope with the MkII Infrared Photometer; the other one (on Julian Date 2446186.4) was made with the MkIII Infrared Photometer on the

Complete list of the 376 photometrically calibrated individual HII regions in the spiral galaxy NGC 628. (1 data file).

We present here a simple approach to understanding the gas cloud mass distribution function by simulating formation and destruction of gas clouds and gas clumps in the ISM. We include as relevant processes coagulation to form bigger clouds, as well as disruption by collisions and the removal of gas by collapse to form stars. We evolve initial sets

Tanto las observaciones como las simulaciones cosmológicas indican que las fusiones de galaxias son procesos bastante frecuentes en el Universo. Sin embargo, aún se desconoce la relevancia de las fusiones en la evolución galáctica y en la constitución de los bulbos actuales frente a otros posibles procesos de formación. El objetivo básico de esta