We construct three extremely different scenarios of the star formation histories applicable to a sample of dwarf galaxies, based on either their present metallicity or their luminosity. The three possible scenarios imply different mechanical energy input rates, and these we compare with the theoretical lower limits established for the ejection of

We present a new sample of 25 fossil groups (FGs) at z

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Several facts regarding the structure of NGC 604 are examined here. The three main cavities produced by the mechanical energy from massive stars, which in NGC 604 are spread over a volume of 106 pc3, are shown here to be undergoing blowout into the halo of M33. High-resolution long-slit spectroscopy is used to track the impact from massive stars

Halo orbits of the earth (Farquhar, 1970) and their stationkeeping control are investigated analytically in the framework of the restricted three-body problem, and numerical algorithms based on the results are demonstrated, summarizing the report of Gomez et al. (1985). The semianalytical approach employed is explained; the halo-orbit neighborhood

The flat-spectrum radio quasar PKS 1222+216 (4C+21.35, z = 0.432) was detected in the very high energy γ-ray band by MAGIC during a highly active γ-ray phase following an alert by the Large Area Telescope (LAT) onboard Fermi. Its relatively hard spectrum (70-400 GeV photon index Γ = 2.7 ± 0.3) without a cut off, together with its observed