Search Publications
Ultraviolet Spectrophotometry of Variable Early-Type Be and B Stars Derived from High-Resolution IUE Data
Smith, Myron A.
High-dispersion IUE data encode significant information about aggregate line absorptions that cannot be conveniently extracted from individual stellar spectra. Here we apply a new technique in which fluxes from each echelle order of a short-wavelength IUE spectrum are binned together to construct low-resolution spectra of a rapidly varying B or Be…
First Detections of Molecular Gas Associated with the Wolf-Rayet Ring Nebula NGC 3199
Marston, A. P.
This paper presents the first observations of molecular gas associated with the Wolf-Rayet ring nebula NGC 3199 around the WR star WR 18. This includes first observations of the molecules HCN, HCO+, CN, and HNC seen in any Wolf-Rayet ring nebula. Our observations immediately suggest the presence of high-density molecular gas (>10
Search for a Near-Infrared Counterpart to the Cassiopeia A X-Ray Point Source
Kulkarni, S. R.; Kaplan, D. L.; Murray, S. S.
We report deep near-infrared and optical observations of the X-ray point source in the Cassiopeia A supernova remnant, CXO J232327.9+584842. We have identified a J=21.4+/-0.3 mag and a Ks=20.5+/-0.3 mag source within the 1 σ error circle, but we believe this source is a foreground Population II star with Teff=2600-2800 K at a…
Ionization, Extinction, and Spiral Structure in the Inner Disk of NGC 1068
Smith, A. M.; Landsman, Wayne; Bruhweiler, Fred C. +2 more
We present our analysis of Hubble Space Telescope/Planetary Camera narrow-bandpass and broadband imagery of the inner 3 kpc region of NGC 1068. Our analysis of F160BW and F547M broadband continuum imagery suggests that roughly 40% of the scattered active galactic nucleus (AGN) continuum emission originates from an unobscured single cloud complex l…
The Interstellar Medium Interactions of a Runaway Luminous Blue Variable Nebula in the Large Magellanic Cloud
Danforth, Charles W.; Chu, You-Hua
New observations of the Magellanic Cloud luminous blue variable candidate S119 (HD 269687) show the relationship of the star to its environs. Echelle spectroscopy and high-resolution Hubble Space Telescope imagery reveal an expanding bubble centered on the star. This bubble appears in both Hα and [N II] and is noticeably brighter on the near (blue…
Active Region Transient Events Observed with TRACE
Reeves, Katharine K.; Golub, Leon; Winebarger, Amy R. +3 more
Nearly all active region observations made by the Transition Region and Coronal Explorer (TRACE) contain seemingly spontaneous, short-lived brightenings in small-scale loops. In this paper, we present an analysis of these brightenings using high-cadence TRACE observations of Active Region 9506 on 2001 June 21 from 15:17:00 to 15:46:00 UT. During t…
Extreme Ultraviolet Explorer Observations of λ Andromedae
Sanz-Forcada, J.; Dupree, A. K.; Brickhouse, N. S.
Extreme-ultraviolet spectra (70-740 Å) and light curves (75-175 Å) of the spectroscopic binary system λ Andromedae (HD 222107) were obtained with the Extreme Ultraviolet Explorer (EUVE) satellite in 1997 July and August. Two flares were detected during the observations that spanned 15 days, or almost 3/4 of the orbital period of 20.5 days, with a …
Hot Outflowing Gas from the X-Ray Binary Hercules X-1
Boroson, Bram; Kallman, Timothy; Vrtilek, Saeqa Dil
We present a unified picture of outflowing gas from the X-ray binary system Hercules X-1/HZ Herculis. We suggest that the outflowing gas (a wind) causes UV emission seen in mid-eclipse, narrow UV absorption lines, and broad UV P Cygni lines. Observations with the FOS and STIS spectrographs on the Hubble Space Telescope (HST) show UV emission lines…
Connecting the Sun and the Solar Wind: Comparison of the Latitudinal Profiles of Coronal and Ulysses Measurements of the Fast Wind
Habbal, Shadia Rifai; Woo, Richard
A quantitative comparison of the latitudinal profile of polarized brightness (pB) measurements nearest the Sun at 1.15 Rsolar by the Mauna Loa Solar Observatory K-Coronameter and Ulysses interplanetary measurements of the fast solar wind during its first south polar pass, at the declining phase of the solar cycle, is made for the first …
Long-Slit Observations of Extended C II λ1335 Emission around V854 Centauri and RY Sagittarii
Clayton, G. C.; Ayres, T. R.
We have obtained long-slit far-ultraviolet (1150-1730 Å) spectra of the R Coronae Borealis (RCB) stars V854 Cen and RY Sgr near maximum light and pulsational phase zero with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. The far-UV spectrum of each star shows a photospheric continuum rising steeply toward longer wave…