Search Publications
A Shock-induced Photodissociation Region in the HH 80/81 Flow: Far-Infrared Spectroscopy
Molinari, Sergio; Noriega-Crespo, Alberto; Spinoglio, Luigi
The two spectrometers on board the Infrared Space Observatory were used to observe the Herbig-Haro objects HH 80, 81, and 80N, as well as their candidate exciting source IRAS 18162-2048. The fine structure lines of [O I] 63 µm, [O I] 145 µm, and [C II] 158 µm are detected everywhere, while [N II] 122 µm and [O III] 88.3 &mi…
Eruption of a Flux Rope on the Disk of the Sun: Evidence for the Coronal Mass Ejection Trigger?
Harra, Louise K.; Mason, Keith O.; Culhane, J. Leonard +1 more
The first evidence of acceleration of a flux rope from the disk of the Sun using the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory (SOHO) is presented. A distinct blueshifted emission component (-480 km s-1) was observed by the EUV spectrometer on SOHO at the start of the impulsive phase of an X2.3 flar…
The Anomalous Infrared Emission of Abell 58
Kimeswenger, Stefan; Koller, Josef
We present a new model to explain the excess in mid- and near-infrared emission of the central, hydrogen-poor dust knot in the planetary nebula (PN) Abell 58. Current models disagree with ISO measurements because they apply an average grain size and equilibrium conditions only. We investigate grain size distributions and temperature fluctuations a…
Evidence for an Accelerating Wind as the Broad-Line Region in NGC 3516
Zheng, W.; Kriss, G. A.; Koratkar, A. P. +4 more
Spectroscopic data in wavelengths 900-3000 Å have been obtained in a low flux state of the nucleus of the Seyfert 1 galaxy NGC 3516. The line profiles show P Cygni characteristics, particularly in O VI λ1032, and are compared with data from an earlier and higher state. The profiles are suggestive of and consistent with an accelerating wind driven …
STIS and GHRS Observations of Warm and Hot Gas Overlying the Scutum Supershell (GS 018-04+44)
Sembach, Kenneth R.; Savage, Blair D.; Howk, J. Christopher
We present Space Telescope Imaging Spectrograph (STIS) and Goddard High Resolution Spectrograph (GHRS) observations of interstellar UV absorption toward HD 177989, a B0 III star at 4.9 kpc in the direction l=17.8d, b=-11.9d. The line of sight passes through the high-latitude ejecta of the Scutum supershell (GS 018-06+44), which is ~5° in diameter …
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…