Our arguments deal with the early evolution of Galactic globular clusters and show why only a few of the supernovae products were retained within globular clusters and only in the most massive cases (M>106 solar masses) while less massive clusters were not contaminated at all by supernovae. Here we show that supernova blast waves evolving in a steep density gradient undergo blowout and end up discharging their energy and metals into the medium surrounding the clusters. This inhibits the dispersal and the contamination of the gas left over from a first stellar generation. Only the ejecta from

Identification of the carriers of the diffuse interstellar bands (DIBs) has been very elusive since the beginning of the last century. Differentcomplex carbon-based molecules - e.g., carbon chains, polycyclicaromatic hydrocarbons (PAHs), and fullerenes - have been proposed asDIB's carriers. If the DIBs arise from large gas phase molecules, such as PAHs and fullerenes, then they are also expected to be present in other carbon-rich space environments like circumstellar shells around evolved stars. Diffuse circumstellar bands (DCBs) in absorption have been unsuccessfully studied for more than

We explore the stellar initial mass function (IMF) of a sample of 49massive quiescent galaxies (MQGs) at 0.9

We present multilevel radiative transfer modeling of the scattering polarization observed in the solar O I infrared triplet around 777 nm. We demonstrate that the scattering polarization pattern observed on the solar disk forms in the chromosphere, far above the photospheric region where the bulk of the emergent intensity profiles originate. We investigate the sensitivity of the polarization pattern to the thermal structure of the solar atmosphere and to the presence of weak magnetic fields (0.01 –100 G) through the Hanle effect, showing that the scattering polarization signals of the oxygen

Microquasars are compact binary stars (a normal very massive star and a compact object), which have an accretion disk around the compact object and an intense and variable radio emission, normally as bipolar jets (symmetric jets of matter in opposite directions). The unusual characteristic of the discovered microquasar in M81 is that the speed of the ejected material is close to the speed of light (that is known as relativistic jets), with a measured velocity of 17% that of light. The main properties of this microquasar all point to a black hole accreting at rates far exceeding the critical

We provide a complete characterization of the astrophysical properties of the σ Ori Aa, Ab, B hierarchical triple system and an improved set of orbital parameters for the highly eccentric σ Ori Aa, Ab spectroscopic binary. We compiled a spectroscopic data set comprising 90 high-resolution spectra covering a total time span of 1963 days. We applied the Lehman-Filhés method for a detailed orbital analysis of the radial velocity curves and performed a combined quantitative spectroscopic analysis of the σ Ori Aa, Ab, B system by means of the stellar atmosphere code FASTWIND. We used our own plus