Search Publications
He I absorption lines in high-redshift Lyman limit systems of the QSO HS 1700+6416.
Reimers, D.; Vogel, S.
We report the detection of He I resonance lines in four high- redshift Lyman limit systems of the QSO HS 1700+6416 (z = 2.72) observed with the Faint Object Spectrograph on board the Hubble Space Telescope. We find neutral hydrogen to neutral helium column density ratios N_HI_/N_HeI_ ~ 30 (possible range 20 to 70). Ionization calculations using CL…
Constraints for the shape of the UV background at z=2.
Reimers, D.; Vogel, S.
Spectroscopic UV observations with the Hubble Space Telescope of the QSO HS 1700+6416 (z = 2.72) (Reimers et al. 1992,1993) offer for the first time the possibility to measure column densities of C, N and O simultaneously in several ionization stages (O III to O VI, C III and C IV, N II to N V). Photoionization models have been computed and fitted…
Hubble Space Telescope Astrometric Observations of Pre-Main Sequence Stars from the HIPPARCOS Program
Badiali, M.; Cardini, D.; Emanuele, A. +6 more
We report on the first set of high angular resolution observations with Fine Guidance Sensor (FGS) #3 aboard the Hubble Space Telescope of a sample of T-Tauri and Herbig Ae/Be pre-main sequence stars, which have also been observed with the HIPPARCOS satellite. Among the 5 Ae/Be stars observed so far of particular interest is the new double HIPPARC…
Compact subarcsec structures of the double nucleus of NGC 6240 revealed with HST.
Boksenberg, A.; Barbieri, C.; Weigelt, G. +18 more
We have used the Faint Object Camera on board of the Hubble Space Telescope to obtain a high spatial resolution ultraviolet image of the central region of NGC 6240. This image resolves the well known double nucleus of the galaxy into several compact knots with sizes 0.1"-0.2" (about 45-90 pc for H_0_ = 75 km s^-1^Mpc^-1^) and extended low surface …
Core sub-structure of elliptical galaxies : the core resolution technique applied to NGC 1399.
Stiavelli, M.; Zeilinger, W. W.; Moller, P.
UBRJK' images, obtained with subarcsecond seeing, are presented and used to derive the core light profile of the elliptical galaxy NGC 1399. These data, combined with an HST PC V band exposure, and high- resolution velocity dispersion data obtained by us are used to show that NGC 1399 is likely to possess a central dark mass concentration. Models …
The radio and optical structure of 3C 66B.
Sparks, W. B.; Macchetto, F.; Miley, G. K. +1 more
We report new, high-resolution radio observations of the jet in 3C 66B. The filaments in the optical jet seen in the HST image of Macchetto et al. are also visible in the radio image. The structure of the radio jet is complex and filamentary beyond the brightest knot. It is consistent with the HST image, which appears to consist of a central kinke…