Search Publications
Evidence for Elemental Variation in the Ejecta of the TYCHO Supernova Remnant
Hughes, John P.; Gorenstein, P.; Vancura, O.
We present an X-ray study of the Tycho supernova remnant utilizing archival data from the high-resolution imagers (HRIs) on Einstein and ROSAT, the low-energy imaging telescopes (LEITs) on EXOSAT, and spectral data from the Broad Band X-ray Telescope (BBXRT). We have made use of the differing HRI bandpasses to construct images of Tycho in two spec…
First Direct Comparison of High and Low Ionization Line Kinematics in Active Galactic Nuclei
Marziani, P.; Moles, M.; Sulentic, J. W. +2 more
We present first results of a comparison of emission line shift properties for the high (HILs) and low (LILs) ionization lines in 43 low- redshift quasars. We identify a core sample of C IV λ1549 and Hβ profiles with a wide distribution of red- and blueshifts (<= 1000 km s^-1^). We also identify two tails in this distribution: one with large Hβ…
Hubble Space Telescope High-Resolution Spectroscopy of the Exposed White Dwarf in the Dwarf Nova VW Hydri in Quiescence: A Rapidly Rotating White Dwarf
Szkody, Paula; Sion, Edward M.; Cheng, Fu-Hua +1 more
We obtained a far-ultraviolet spectrum of the dwarf nova VW Hyi in quiescence, with the Hubble Space Telescope Goddard High Resolution Spectrograph covering the region of the Si iv lambda(lambda)1393, 1402 resonance doublet. The broad, shallow Si iv doublet feature is fully resolved, has a total equivalent width of 2.8 A, and is the first metal ab…
A Critical Analysis of Interstellar Zn and CR as Galactic Abundance Benchmarks for Quasar Absorbers
Steidel, Charles C.; Sembach, Kenneth R.; Meyer, David M. +1 more
We present interstellar gas-phase abundances of zinc and chromium in the Milky Way for comparison with the abundances of these elements in damped Lyα systems at redshifts near z ~ 2. We make use of both IUE and GHRS archival information in deriving the Milky Way values and find that the average difference in [Zn/H] and [Cr/Zn] between the Milky Wa…
The X-Ray Halo of Nova V1974 Cygni (Nova Cygni 1992) and the Nature of Interstellar Dust
Krautter, J.; Mathis, John S.; Finley, John P. +1 more
Nova V1974 Cygni (Nova Cygni 1992) was observed by ROSAT as a very bright soft X-ray source, with its point source image surrounded by an extensive halo caused by scattering from interstellar grains. We have analyzed the halo of 1992 December 6, using the standard extinction law (R = 3.1) as an additional constraint on the size distribution of the…
Relation between O VI Emission and X-Ray Intensity in Active Galactic Nuclei
Kriss, Gerard A.; Zheng, Wei; Davidsen, Arthur F.
Based on HUT observations of two Seyfert 1 galaxies and lUE and HST observations of 30 QSOs, we find a correlation between the ratio of O VI λ1034 to Lyα λ1216 and the effective power-law index between 2500 Å and 2 keV: log (O VI/Lyα) = -0.74 αOX + 0.38. From X-ray-strong to weak objects the O VI/Lyα ratio decreases by a factor of ∼8. S…
Ultraviolet Interstellar Linear Polarization. II. The Wavelength Dependence
Clayton, Geoffrey C.; Wolff, Michael J.; Allen, R. G. +1 more
We present new ultraviolet (UV) polarimetry of the well-studied interstellar line of sight toward HD 204827 obtained with the Faint Object Spectrograph on Hubble Space Telescope. HD 204827 is of great interest because the dust along this line of sight has extremely low values of both lambdamax and RV. Its far-UV extinction is…
The Emission-Line Jet in Markarian 6*
Boksenberg, A.; Capetti, A.; Sparks, W. B. +4 more
We present the results of Hubble Space Telescope (HST) and MERLIN observations of the Seyfert 1.5 galaxy Mrk 6. FOC/HST images reveal a jetlike feature in the emission line which extends ~0."5, or 250 pc, from the nucleus. The optical jet is cospatial with the southern radio jet, as revealed by a 6 cm MERLIN image matching the HST angular resoluti…
Wind Variability of B Supergiants. I. The Rapid Rotator HD 64760 (B0.5 Ib)
Massa, Derck; Prinja, Raman K.; Fullerton, Alexander W.
Stellar Photometry in the Inner Bulge of M31 Using the Hubble Space Telescope Wide Field Camera
Rich, R. M.; Mighell, K. J.
We present photometry of two fields in the M31 bulge imaged with the Hubble Space Telescope (HST) Wide-Field Camera. The nuclear field (r <40" = 150 pc) giant branch extends to I = 19.5, M_I_ = - 5 (Cousins system), a full 0.9 mag brighter than the giant-branch tips of metal-poor Galactic globular clusters and M31 halo fields. This is also ~1.5…