Uno de los parámetros mas relevantes en la descripción del Universo es la densidad bariónica media. Esta ha sido estimada a través de las abundancias de los elementos primordiales y confirmada en estudios recientes del espectro de potencias del Fondo Cósmico de Microondas (FCM). Sin embargo, las observaciones de la materia bariónica en el universo

Very low metallicity massive stars are a key piece to understanding the infant, extremely metal-poor Universe and its early development. Our models for these objects rely to a great extent on the theory of radiation driven winds, important agents of stellar evolution and feedback. However, the theory of radiation driven winds has only been

We describe the discovery of a likely brown dwarf (BD) companion with a minimum mass of 31.7 ± 2.0 M Jup to GSC 03546-01452 from the MARVELS radial velocity survey, which we designate as MARVELS-6b. For reasonable priors, our analysis gives a probability of 72% that MARVELS-6b has a mass below the hydrogen-burning limit of 0.072 M ☉, and thus it is

We obtained optical and near-infrared images with VRIJHKs filters between 2010 September 19 and 2012 October 12 using four telescopes: the Schmidt and RCC telescopes of the Konkoly Observatory (Hungary), as well as the IAC-80 and Telescopio Carlos Sanchez (TCS) telescopes of the Teide Observatory in the Canary Islands (Spain). We observed V2492 Cyg

Stellar archaeology shows that massive elliptical galaxies formed rapidly about ten billion years ago with star-formation rates of above several hundred solar masses per year. Their progenitors are probably the submillimetre bright galaxies at redshifts z greater than 2. Although the mean molecular gas mass (5×1010 solar masses) of the

We present a 30-day monitoring campaign of the optical counterpart of the bright X-ray transient Swift J1745-26, starting only 19 min after the discovery of the source. We observe the system peaking at i' ˜ 17.6 on day six (MJD 561 92) to then decay at a rate of ˜0.04 mag d-1. We show that the optical peak occurs at least 3 d later than the hard X