Context: UV observations of some massive globular clusters have revealed a significant population of very hot stars below the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either as a result of the late hot flasher scenario where stars experience the helium flash while on the white dwarf

Aims:We present multiwavelength (X-ray/optical/near-infrared/millimetre) observations of GRB 051022 between 2.5 h and 1.15 yr after the event. It is the most intense gamma-ray burst ( 10-4 erg cm-2) detected by HETE-2, with the exception of the nearby GRB 030329. Methods: Optical and near infrared observations did not detect the afterglow despite a

We summarize the results of a chemical analysis of a sample of 23 galactic R stars (cool and warm spectral types) with accurate parallaxes measured by Hipparcos.

Aims:The detection and measurement of acoustic modes on the giant planets of the solar system is of great interest for the study of the internal structure and evolution of the giant planets, as well as the study of the solar system formation. Such observations require a dedicated instrument and observing procedure. Methods: We describe the

We report optical spectroscopy of the putative optical counterpart to the Swift source J052522.48+241331.8 (Page, Tueller & Beardmore 2007, ATEL #1279). We note that the XRT position (ATEL #1279) is consistent with that of the ROSAT source 1RXS J052523.2+241331. Using the X-ray flux and power-law model reported in ATEL #1279, we computed with

Using the combined capabilities of the large near-infrared Palomar/DEEP-2 survey, and the superb resolution of the Advanced Camera for Surveys HST camera, we explore the size evolution of 831 very massive galaxies (M* >= 1011h-270Msolar) since z ~ 2. We split our sample according to their light concentration using the Sérsic index n. At a given