An analysis of a ROSAT/PSPC observation of the galaxy cluster A2634 is presented. The cluster has a luminosity of 7.9+/-0.1x10^43^erg/s in the ROSAT band (0.1-2.4keV). The temperature profile decreases from about 3keV in the outer parts to 1.2keV in the centre. Within a radius of 1.5Mpc the gas mass of the cluster is 0.51x10^14^Msun_ and the total

PSR B1951+32 is a gamma -ray pulsar detected by the Energetic Gamma Ray Experiment Telescope (EGRET) and identified with the 39.5 ms radio pulsar in the supernova remnant CTB 80. The pulsar energy spectrum is consistent with an unbroken power law with differential photon index of -1.8 +/- 0.1 between 50 MeV and 10 GeV. The EGRET data shows no

We present a study of the MgII absorption system at z=0.558 towards the BL Lac object PKS 0118-272 based on high resolution spectra (λ/{DELTA}λ=~2x10^4^) obtained at the 3.6m ESO telescope and on direct imaging data obtained at the 3.5m ESO New Technology Telescope. At the redshift of the absorber we detect lines of the low ionization species MgI

The Universe at Large presents a unique survey of key questions outstanding in contemporary astronomy and cosmology. In this timely volume, eleven of the world's greatest living astronomers and cosmologists present personal views of what problems must be addressed by future research. Allan Sandage presents a 23-point plan to reach a full

In this Letter we report new evidence for a close three-galaxy interaction in the compact group of galaxies HCG 95. Deep optical imaging in the Johnson UBVRI bands and in narrowband H alpha have shown four long tidal tails emanating from the two disk galaxies as well as signs of transfer of material between one of the tidal tails and the elliptical

We have tested current models for the atmospheres (including photosphere and low chromosphere) of late-type stars using the D resonance lines of neutral sodium as a diagnostic. To this end, we have measured the equivalent widths of the D lines for a sample of 39 dwarf and 45 giant late-type stars observed with high spectral resolution. We