8 papers · 1 filter
Very-High-Energy Gamma Rays from a Distant Quasar: How Transparent Is the Universe?
MAGIC Collaboration, J. Albert
The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar R…
Periodic very high energy gamma-ray emission from LS I +61 303 observed with the MAGIC telescope
MAGIC Collaboration, J. Albert
The MAGIC collaboration has recently reported the discovery of gamma-ray emission from the binary system LS I +61 303 in the TeV energy region. Here we present new observational re…
On the potassium-rotation connection in late-type Alpha Persei stars
Eduardo L. Martin, Antonio Magazzu, Ramon J. Garcia Lopez +2
We present measurements of the \ion{K}{i} line from spectra of 19 late-type members of the Persei cluster obtained with the Intermediate Dispersion Spectrograph at the I…
Galactic Evolution of Nitrogen
G. Israelian, A. Ecuvillon, R. Rebolo +3
We present detailed spectroscopic analysis of nitrogen abundances in 31 unevolved metal-poor stars analysed by spectral synthesis of the near-UV NH band at 3360 A observed at high…
Galactic Evolution of Beryllium and Oxygen
Garik Israelian, Ramon Garcia Lopez, Rafael Rebolo
We discuss the early evolution of beryllium and oxygen in our Galaxy by comparing abundances of these elements for halo and disk metal-poor stars. Both, O and Be rise as we go prog…
Beryllium abundances in parent stars of extrasolar planets: 16 Cyg A & B and rho 1 Cnc
R. J. Garcia Lopez, M. R. Perez de Taoro
The Be II 3131 A doublet has been observed in the solar-type stars 16 Cyg A & B and in the late G-type star rho 1 Cnc, to derive their beryllium abundances. 16 Cyg A & B show simil…