We are now in an era of large spectroscopic surveys of OB-type stars. Quantitative spectroscopic analysis of these modern datasets is enabling us to review the physical properties of blue massive stars with robust samples, not only revisiting mean properties and general trends, but also incorporating information about the effects of second-order parameters. We investigate the spectral type -- effective temperature (SpT - Teff) calibration for O-type dwarfs, and its claimed dependence on metallicity, using statistically-meaningful samples of stars extracted from the IACOB and VFTS surveys. We

Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20%

For the first time we use self-consistent evolutionary models of low-and intermediate-mass stars (1-8 solar masses) coupled with theoretical dust formation models to follow the evolution of these stars during the Asymptotic Giant Branch (AGB) in the Spitzer Space Telescope two-color and color-magnitude diagrams. These models are the first able to identify the main regions in the Spitzer diagrams occupied by AGB stars in the Large Magellanic Cloud (LMC). The main diagonal sequences traced by LMC extreme stars in the two-color and color-magnitude Spitzer diagrams are nicely fit by carbon stars

Three decades ago one of the first astronomical satellites designed toobserve X-rays detected a new type of object: it had a much higher luminosity than any star, but much lower than other types of identified sources, such as the nuclei of active galaxies. They were dubbed, in a not very imaginative way, ultraluminous X rays (ULX) sources. Even recently we were still not really sure what they are. In this work, we have managed to solve this mystery and we have found that the mechanism which produces such a large luminosity in the most thoroughly studied ULX is not, as many had hoped, an

Happy New Year 2014 from the Instituto de Astrofísica de Canarias (IAC)

With the Canaricam instrument on the Gran Telescopio CANARIAS (GTC), a team of researchers known as ‘Los Piratas’ have caught a system of two galaxies fused together in collision, feeding two black holes at their centres