Phoenix spectra of C_2, CN and CO lines will provide oxygen isotopic abundance ratios (^16O/^17O/^18O) and CNO abundances for cool R Coronae Borealis (RCB) stars. The ratios, especially the ^16O/^18O ratio, will be used to test the two leading scenarios for RCB production. These observations were prompted by Clayton et al.'s striking discovery of

Ring-shaped morphologies of nuclear star-forming regions within the central 40{-}200 pc of disk galaxies have been barely resolved so far in three composite Sy 2 nuclei, the Sy 2 Circinus galaxy and in three non-AGN galaxies. Such morphologies resemble those of the standard 1 kpc-size nuclear rings that lie in the inner Lindblad resonance regions

We present the discovery of a companion near the deuterium-burning mass limit located at a very wide distance, at an angular separation of 4.6''+/-0.1'' (projected distance of ~ 670 AU) from UScoCTIO 108, a brown dwarf of the very young Upper Scorpius association. Optical and near-infrared photometry and spectroscopy confirm the cool nature of both

Aims:The “bright” High Frequency Peakers (HFPs) sample is a mixture of blazars and intrinsically small and young radio sources. We investigate the polarimetric characteristics of 45 High Frequency Peakers, from the “bright” HFP sample, in order to have a deeper knowledge of the nature of each object, and to construct a sample made of genuine young

We present simultaneous high time resolution (1-10 Hz) X-ray and optical observations of the persistent LMXBs Sco X-1 and V801 Ara( = 4U 1636-536). In the case of Sco X-1 we find that the Bowen/HeII emission lags the X-ray light-curves with a light travel time of ~11-16 s which is consistent with reprocessing in the donor star. We also present the

New z-band (F850LP, denoted z850 hereafter) imaging was obtained with the ACS camera onboard HST in November 2004 (AC114) and July 2005 (Abell 1835). The 3.6, 4.5, 5.8, and 8.0{mu}m images were obtained using the Infrared Array Camera (IRAC), while the 24{mu}m images were obtained using the Multi-band Imaging Photometer for Spitzer (MIPS), both