Blue compact dwarf galaxies (BCDs) take up the low end of the distribution of metallicity and nitrogen-to-oxygen (N/O) ratio as derived using collisional emission lines in ionized gaseous nebulae. This chemical status is well explained by chemical evolution models. Nevertheless, there is a subsample of BCDs with large values of N/O which cannot be

We present results on the evolution in the last 6 Gyr of the structural parameters of two samples of brightest cluster galaxies (BCGs). The nearby sample of BCGs consist on 69 galaxies from the WINGS survey spanning a redshift range of 0.04

Discoveries of very high energy (VHE) photons from distant blazars suggest that, after correction by extragalactic background light (EBL) absorption, there is a flatness or even a turn-up in their spectra at the highest energies that cannot be easily explained by the standard framework. Here, it is shown that a possible solution to this problem is

The spectral predictions of stellar population models are not as accurate in the ultra-violet (UV) as in the optical wavelength domain. One of the reasons is the lack of high-quality stellar libraries. The New Generation Stellar Library (NGSL), recently released, represents a significant step towards the improvement of this situation. To prepare

Photometric observations made by the NASA Kepler Mission have led to a dramatic increase in the number of main-sequence and subgiant stars with detected solar-like oscillations. We present an ensemble asteroseismic analysis of 76 solar-type stars. Using frequencies determined from the Kepler time-series photometry, we have measured three

Archaeoastronomy is a discipline apparently subject to controversy. The reason for this is that it is situated between astronomy, whose tools it uses; and anthropology, archaeology, and history, the disciplines archaeoastronomy serves and within whose epistemological framework should be integrated. Perhaps for this reason, until recently it has not