Main Belt Comets (MBCs) are objects of the main belt with observed sporadic cometary-like activity (Hsieh and Jewitt 2006, Science, 312, 561). The study of asteroids that present sporadic cometary activity is of fundamental importance to address several astronomical problems including the end states of comet nuclei, the abundance of water in main

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We report on the X-ray aperiodic timing analysis of two accreting millisecond pulsars: XTE J1807-294 and IGR J00291+5934. On the one hand, we discovered in XTE J1807-294 seven pairs of simultaneous kilohertz quasi-periodic oscillations (kHz QPOs) separated in frequency by nearly the spin frequency of the neutron star. This confirms the suspected

Numerous spectroscopic studies have shown that stars with giant planets are particularly metal-rich when compared with field stars in the solar neighbourhood. I will review the most recent results concerning the study of the chemical abundances of planet-host stars and will present distributions for several elements, including those of alpha and

Recent high-resolution imaging observations with Chandra have unveiled a striking similarity between the Narrow Line Region (NLR) and the diffuse soft (0.1-keV) emission-line dominated X-ray morphologies in a number of obscured Active Galactic Nuclei (AGN) on scales as large as 0.1-2kpc (Bianchi et al., 2006, A&, 448, 499). This discovery suggests

Context: Large surveys such as the Sloan Digital Sky Survey have made large amounts of spectroscopic and photometric data of galaxies available, thereby providing important information for studying galaxy evolution in dense environments. Aims: We have selected a sample of 88 nearby (z 0.1) galaxy clusters from the SDSS-DR4 with redshift