We have discovered a ˜420-d modulation, with associated X-ray dips, in Rossi X-Ray Timing Explorer-All Sky Monitor/Monitor of All-Sky X-ray Image/Swift-Burst Alert Telescope archival light curves of the short-period (3.2 h) black hole X-ray transient, Swift J1753.5-0127. This modulation only appeared at the end of a gradual re-brightening

We report the discovery of 76 new T dwarfs from the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). Near-infrared broad- and narrow-band photometry and spectroscopy are presented for the new objects, along with Wide-field Infrared Survey Explorer (WISE) and warm-Spitzer photometry. Proper motions for 128 UKIDSS T dwarfs are

Context. It has recently been discovered that the Galactic bulge is X-shaped, with the two southern arms of the X both crossing the lines of sight at l = 0 and | b| > 4, hence producing a double red clump in the bulge color magnitude diagram. Dynamical models predict the formation of X-shaped bulges as extreme cases of boxy-peanut bulges. However

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