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The number of present day massive galaxies that have survived untouched since their formation at high-z is an important observational constraint to the hierarchical galaxy formation models. Using three different semianalytical models based on the Millenium simulation, we quantify the expected fraction and number densities of the massive galaxies

Star formation (SF) in the galaxy populations of local massive clusters is reduced with respect to field galaxies, and tends to be suppressed in the core region. Indications of a reversal of the SF-density relation have been observed in a few z > 1.4 clusters. Using deep imaging from 100-500 μm from Photodetector Array Camera and Spectrometer (PACS

Residual Spitzer/Infrared Spectrograph spectra for a sample of 31 R Coronae Borealis (RCB) stars are presented and discussed in terms of narrow emission features superimposed on the quasi-blackbody continuous infrared emission. A broad ~6-10 μm dust emission complex is seen in the RCBs showing an extreme H-deficiency. A secondary and much weaker

We describe the presence of wave front dislocations in magnetohydrodynamic waves in stratified stellar atmospheres. Scalar dislocations such as edges and vortices can appear in Alfvén waves, as well as in general magnetoacoustic waves. We detect those dislocations in observations of magnetohydrodynamic waves in sunspots in the solar chromosphere

We report the discovery of kHz quasi-periodic oscillations (QPOs) in three Rossi X-ray Timing Explorer observations of the low-mass X-ray binary XTE J1701-407. In one of the observations we detect a kHz QPO with a characteristic frequency of 1153 ± 5 Hz, while in the other two observations we detect twin QPOs at characteristic frequencies of 740 ±