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Spectroscopic study of the planetary nebulae with Wolf-Rayet nuclei in the Magellanic Clouds.
Pena, M.; Torres-Peimbert, S.; Ruiz, M. T.
UV and optical spectrophotometric data of planetary nebulae with WR nuclei in the Magellanic Clouds are presented. Analysis of the nebular characteristics shows that the ionized gas, in all the objects, is extremely C-rich, probably due to contamination with freshly-made C from stellar nucleosynthesis. Very high electron densities are found (N_e_&…
Blue stars in the center of the S0 galaxy NGC 5102.
Crane, P.; Disney, M. J.; Jedrzejewski, R. +2 more
The S0 galaxy NGC 5102 has been observed with the Faint Object Camera on-board the Hubble Space Telescope. Individual blue stars have been resolved in the central region and measured photometrically through the F175W and F342w filters. The limits of detection and completeness are not uniform over the field observed because the unresolved galaxy li…
An Interstellar Conduction Front within a Wolf-Rayet Ring Nebula Observed with the Goddard High Resolution Spectrograph
Chu, You-Hua; McCray, Richard; Boroson, Bram +4 more
With the High Resolution Spectrograph aboard the Hubble Space Telescope we obtained high signal-to-noise ratio (S/N >~ 200-600 per 17 km s-1 resolution element) spectra of narrow absorption lines toward the Wolf-Rayet star HD 50896. The ring nebula S308 that surrounds this star is thought to be caused by a pressure-driven bubble boun…
HST polarization observations of the jet of M87.
Macchetto, F. D.; Capetti, A.; Sparks, W. B. +1 more
We present the results of pre-refurbishment HST polarization observations of the jet of M 87 taken with the Faint Object Camera in the ultraviolet and with the WF/PC-I in the visual. From these observations we produce polarization maps of unprecedentedly high resolution. The structure of the projected magnetic field is extremely complex and change…
UV to X-ray spectra of radio-quiet quasars. Comparison with accretion disk models.
Brunner, H.; Staubert, R.; Mueller, C. +3 more
We present UV to soft X-ray spectra of 31 radio-quiet quasars, comprising data from the IUE ULDA database and the ROSAT pointed observation phase. 90 % of the sample members show a soft X-ray excess above an underlying hard X-ray power law spectrum. Particularly for the steep X-ray spectrum (α_energy_>1.5), low redshift subsample (17 objects) t…
Motion of the Ultraviolet R Aquarii Jet
Feibelman, W. A.; Hollis, J. M.; Dorband, J. E. +1 more
We present evidence for subarcsecond changes in the ultraviolet (~2550 Å) morphology of the inner 5 arcseconds of the R Aqr jet over a 2 yr period. These data were taken with the Hubble Space Telescope (HST) Faint Object Camera (FOC) when the primary mirror flow was still affecting observations. Images of the R Aqr stellar jet were successfully re…
The Nature and Origin of za ~ ze Absorption Lines in the Redshift 0.20 Quasar, PKS 2135-147
Hamann, Fred; Cohen, Ross D.; Burbidge, E. M. +3 more
We use new UV and optical spectra and an archival Hubble Space Telescope Wide Field Planetary Camera 2 (HST-WFPC2) image to study the za ~ ze absorber in the ze ~ 0.20 QSO PKS 2135-147. The UV spectra, obtained with the Faint Object Spectrograph on HST, show strong za ~ ze absorption lines of …
The Wave Experiment Consortium (wec)
Alleyne, H. St. C.; Thompson, J. A.; Gurnett, D. +13 more
Using energetic particles to probe the magnetic topology of ejecta
Richardson, I. G.
Observations of energetic particles over a wide range of rigidities can provide information on the presence of ejecta, and their structure. A large fraction of ejecta produce a local, few percent depression of the cosmic ray density. The depression typically extends over the ejecta region as determined from a range of ejecta signatures, in particu…
Star Formation and Metal Production as a Function of Redshift: The Role of the Multiphase ISM
Carollo, C. Marcella; Spaans, Marco
We present models of the cosmological star formation and metal production history of (proto)galaxies with varying axis ratios. More massive and/or roughly spherical systems reach the threshold metallicity for the transition to a multiphase interstellar medium earlier than less massive and/or more flattened systems. Therefore, more flattened and/or…