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The X-ray spectrum of the superluminal quasar 1928+73.
Ghosh, K. K.; Soundararajaperumal, S.
EXOSAT observations (0.1-10 keV) of the radio-loud quasar 1928+73, which displays superluminal motion, were made at four epochs between 1983/283 and 1984/009, and we obtained spectra of this source from the EXOSAT database. The X-ray spectrum (0.1-10 keV) can be explained by a power law and uniform absorption model. No significant low-energy absor…
The radial velocity and binary of X Persei.
Stickland, D. J.
It is shown on the basis of radial velocity measurements on high-resolution spectra of X Persei from the IUE archive that there is no variation above the level of a few km/s and thus no need for a massive unseen component in the system. This does not rule out a neutron star or white dwarf orbiting in the variable wind of the Be star.
How fast is the evolution of the diffuse ultraviolet cosmic background radiation ?
Stanek, Krzysztof Z.
Lyα absorption lines observed in Hubble Space Telescope UV spectra of 3C 273 have neutral hydrogen column densities comparable with those of z ~ 2 quasars. Assuming the standard pressure-confined model of Lyα clouds, we use this fact to determine the evolution of UV background radiation for z < 2. We find that to fit the data the UV background …