OSIRIS is a Day One instrument that will be available at the 10m GTC telescope which is being built at La Palma observatory in the Canary Islands. This optical instrument is designed to obtain wide-field narrow-band images using tunable filters and to do low-resolution spectroscopy in both long-slit and multislit modes. For the multislit

The solar photospheric oxygen abundance has been determined from [O I], O I, OH vibration-rotation and OH pure rotation lines by means of a realistic time-dependent, 3D, hydrodynamical model of the solar atmosphere. In the case of the O I lines, 3D non-LTE calculations have been performed, revealing significant departures from LTE as a result of

The INTEGRAL/EINSTEIN/ROSAT/NVSS objects IGR J17418-12122, 2E 1739.1-1210, 1RXS J174155.3-121157 and NVSS J174155-121201 have recently been suggested to be the same and considered to be a microquasar candidate with likely counterparts at optical and IR wavelengths (Tsarevsky et al. 2004, ATEL #239; Bassani et al. 2004, ATEL #232). In order to

We fitted the surface-brightness profiles of 21 elliptical galaxies using both the Sérsic function and a new empirical model that combines an inner power law with an outer Sérsic function. The profiles are combinations of deconvolved Hubble Space Telescope (HST) profiles from the literature and ellipse fits to the full WFPC2 mosaic images and thus

J2000 coordinates, redshifts and equivalent widths of Hα and [OII]3727 are presented for a sample of 79 galaxies in the clusters VMF73 and VMF74 at respective redshifts of z=0.25 and z=0.18. (1 data file).

We report the discovery of the optical counterpart to the X-ray transient XTE J1748-361 using the 6.5m Magellan-Clay telescope at Las Campanas Observatory. Several 5-minute images in the V and R bands were obtained using the MagIC camera on May 31 as well as November 9 2003 when the object was reported in outburst (ATEL #204). Seeing conditions