A study published in the Astrophysical Journal supports models which question the need for the existence of this form of matter in galaxies

It will be its closest approach to the Earth (its perigee), at a distance of around 107 million kilometres, which is very close, considering that it originated in the Oort Cloud, at a distance from us of about a light year (some 9.5 billion kilometres). Although on those nights it will attain maximum brightness, it has not been as bright as was expected, so that it is not easy to find it with the naked eye. So binoculars are necessary, and a sky map, and we need to be at a place with dark sky to see the central zone of the comet. In spite of that it can be found near the Great Bear, and this

El presidente del Gobierno de Canarias visita el IAC Hoy, viernes 8 de enero, el presidente del Gobierno de Canarias, Fernando Clavijo, ha visitado la sede del Instituto de Astrofísica de Canarias (IAC), en La Laguna, para reunirse personalmente con el Director del centro, Rafael Rebolo, y conocer de primera mano los proyectos en los que está involucrado el Instituto. En dicho encuentro, se le han planteado distintos asuntos que conciernen al estado actual del IAC, como el progreso de su plan estratégico y el de las grandes instalaciones telescópicas para los Observatorios de Canarias

Previous numerical studies had apparently ruled out the possibility that flares in galaxy discs could give rise to the apparent breaks in their luminosity profiles when observed edge-on. However the studies have not, until now, analysed this hypothesis systematically using realistic models for the disc, the flare, and the bulge. We revisit this theme by analysing a series of models which sample a wide range of observationally based structural parameters for these three components. Using observational data, we have considered realistic distributions of bulge-to-disc ratios, morphological

Historically, globular clusters (GCs) have been used as laboratories for studying stellar evolution, because it was thought that all the stars in a globular cluster formed at the same time and thus have the same age. However since a couple of decades ago it has been known that almost all the globular clusters contain several stellar populations. In the first generation the chemical abundances, for example those of elements such as Al and Mg, show the composition of the original interstellar (or intra-cluster) medium. In the short time (astronomically) of only 500 million years the medium is

Ultra diffuse galaxies (UDGs) have the sizes of giants but the luminosities of dwarfs. A key to understanding their origins comes from their total masses, but their low surface brightnesses (mu > 25.0) generally prohibit dynamical studies. Here we report the first such measurements for a UDG (VCC 1287 in the Virgo cluster), based on its globular cluster system dynamics and size. From 7 GCs we measure a mean systemic velocity Vsys = 1071(-15+14) km/s, thereby confirming a Virgo-cluster association. We measure a velocity dispersion of 33(-10+16) km/s within 8.1 kpc, corresponding to an