We present here a new theoretical model designed to explain the interstellar dust grain size distribution function (IDGSDF), and compare its results with previous observationally derived distributions and with previous theoretical models. The range of grain sizes produced in the late stages of stars with different masses is considered, and folded

Several authors have studied the dependence of galaxy properties on environment in order to understand which mechanisms operate in the galaxy evolution. Recently, some of them have proposed that intermediate densities could be sites where local environment influences the transition of galaxies onto the red-sequence, as opposed to mechanisms that

Active Galactic Nuclei (AGN) play an important role in many aspects of modern cosmology. One of the fundamental goals in cosmology is to determine the fraction of galaxies having AGN as a function of its morphology, environment, redshift, etc., and conversely, to determine how an AGN affects other galaxy properties, and which is the mechanism of

Asteroseismology of stars in clusters has been a long-sought goal because the assumption of a common age, distance, and initial chemical composition allows strong tests of the theory of stellar evolution. We report results from the first 34 days of science data from the Kepler Mission for the open cluster NGC 6819—one of the four clusters in the

On April 10th, it was discovered (ATel #2548) using INTEGRAL that the neutron-star X-ray binary Swift J1749.4-2807 (Wijnands et al. 2009, MNRAS, 393, 126) was again in outburst. Using follow-up Swift and INTEGRAL observations the source activity was confirmed (ATel #2548 and #2561). On April 14th, 2010 (20:58:00 UT), RXTE performed a pointed

Metabolism and self-replicating are characteristics considered to be indispensable for the existence of life on earth.