We report simultaneous X-ray and optical observations of V404 Cyg in quiescence. The X-ray flux varied dramatically by a factor of >~20 during a 60 ks observation. X-ray variations were well correlated with those in Hα, although the latter include an approximately constant component as well. Correlations can also be seen with the optical continuum

The currently available values and confidence limits for Ωm0, H0 and globular cluster ages still indicate that the dark energy that dominates the Universe could also be a form of quintessence or phantom energy. In fact, current cosmological values favor phantom energy. To increase the likelihood of a cosmological constant as dark energy instead of

The Constellation-X mission is a high through-put X-ray facility, emphasizing observations at high spectral resolution (Delta E/E 300 to 3000) while covering a broad energy band up to 60 keV. Constellation-X is the x-ray astronomy equivalent of large ground-based optical telescopes such as the Keck and the VLT, complementing the high spatial

We have monitored S Ori 45, a young, low-mass (20 M j up) brown dwarf of the σ Orionis cluster (˜3 Myr, 352 pc), using optical and near-infrared filters. S Ori 45 (spectral type M8.5) is found to be multi-periodic with a dominant modulation at 2.5 3.5 h, and a short modulation at about 46 min. We ascribe the longer of these modulations to a

We present echelle spectrophotometry of the Galactic H II region NGC 3576. The data have been taken with the VLT UVES echelle spectrograph in the 3100-10400 Å range. We have measured the intensities of 458 emission lines, 344 are permitted lines of H0, He0, C+, N0, N+, N++, O0, O+, Ne+, S++, Si0, Si+, Ar0, and Ar+; some of them are produced by

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