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A Quantitative Comparison of the Small Magellanic Cloud, Large Magellanic Cloud, and Milky Way Ultraviolet to Near-Infrared Extinction Curves
Gordon, Karl D.; Clayton, Geoffrey C.; Misselt, K. A. +2 more
We present an exhaustive quantitative comparison of all the known extinction curves in the Small and Large Magellanic Clouds (SMC and LMC) with our understanding of the general behavior of Milky Way extinction curves. The RV-dependent CCM relationship of Cardelli, Clayton, and Mathis and the sample of extinction curves used to derive th…
Constraints on the Ionization Balance of Hot-Star Winds from FUSE Observations of O Stars in the Large Magellanic Cloud
Sonneborn, G.; Massa, D.; Hutchings, J. B. +1 more
We present Far Ultraviolet Spectroscopic Explorer (FUSE) spectra for 25 O stars in the Large Magellanic Cloud. We analyze wind profiles for the resonance lines from C III, N III, S IV, P V, S VI, and O VI in the FUSE range using a ``Sobolev with exact integration'' method. In addition, the available data from either IUE or the Hubble Space Telesco…
Anomalous Ultraviolet Line Flux Ratios in the Cataclysmic Variables 1RXS J232953.9+062814, CE 315, BZ Ursae Majoris, and EY Cygni, Observed with the Hubble Space Telescope Space Telescope Imaging Spectrograph
Szkody, Paula; Sion, Edward M.; Hubeny, Ivan +6 more
Brief Hubble Space Telescope Space Telescope Imaging Spectrograph spectroscopic snapshot exposures of the cataclysmic variables 1RXS J232953.9+062814, CE 315, BZ UMa, and EY Cyg reveal very large N V/C IV line flux ratios, similar to those observed in AE Aqr. Such anomalous line flux ratios have so far been observed in 10 systems and presumably re…
Dust Grain Size Distributions from MRN to MEM
Sofia, Ulysses J.; Gordon, K. D.; Clayton, Geoffrey C. +2 more
Employing the maximum entropy method (MEM) algorithm, we fit interstellar extinction measurements that span the wavelength range 0.125-3 µm. We present a uniform set of MEM model fits, all using the same grain materials, optical constants, and abundance constraints. In addition, we are taking advantage of improved UV and IR data and better e…
Simultaneous Ultraviolet and X-Ray Spectroscopy of the Seyfert 1 Galaxy NGC 5548. I. Physical Conditions in the Ultraviolet Absorbers
Kaastra, J. S.; Turner, T. J.; Kraemer, S. B. +9 more
We present new UV spectra of the nucleus of the Seyfert 1 galaxy NGC 5548, which we obtained with the Space Telescope Imaging Spectrograph at high spectral resolution, in conjunction with simultaneous Chandra X-Ray Observatory spectra. Taking advantage of the low UV continuum and broad emission-line fluxes, we have determined that the deepest UV a…
Deuterium toward Two Milky Way Disk Stars: Probing Extended Sight Lines with the Far Ultraviolet Spectroscopic Explorer
Hoopes, Charles G.; Sembach, Kenneth R.; Hébrard, Guillaume +2 more
We have carried out an investigation of the abundance of deuterium along two extended sight lines through the interstellar medium (ISM) of the Galactic disk. The data include Far Ultraviolet Spectroscopic Explorer (FUSE) observations of HD 195965 (B1 Ib) and HD 191877 (B0 V), as well as Space Telescope Imaging Spectrograph (STIS) observations of H…
A Far-Ultraviolet Survey of 47 Tucanae. II. The Long-Period Cataclysmic Variable AKO 9
Zurek, David R.; Gilliland, Ronald L.; Shara, Michael M. +2 more
We present time-resolved far-ultraviolet (FUV) spectroscopy and photometry of the 1.1 day eclipsing binary system AKO 9 in the globular cluster 47 Tucanae. The FUV spectrum of AKO 9 is blue and exhibits prominent C IV and H II emission lines. The spectrum broadly resembles that of long-period cataclysmic variables (CVs) in the Galactic field. Comb…
The Spatial Distribution of Fluorescent H2 Emission near T Tauri
Raymond, John; Hartmann, Lee; Calvet, Nuria +1 more
New subarcsecond far-UV observations of T Tau with Hubble Space Telescope STIS show spatially resolved structures in the 2''×2'' area around the star. The structures are apparent in multiline emission of fluorescent H2 pumped by Lyα. One emission structure follows the cavity walls observed around T Tau N in scatter…
Small Magellanic Cloud-Type Interstellar Dust in the Milky Way
Gordon, Karl D.; Clayton, Geoffrey C.; Valencic, Lynne A. +1 more
It is well known that the sight line toward HD 204827 in the cluster Trumpler 37 shows a UV extinction curve that does not follow the average Galactic extinction relation. However, when a dust component, foreground to the cluster, is removed, the residual extinction curve is identical to that found in the SMC within the uncertainties. The curve is…
The Remarkable Alternating Spectra of the Of?p Star HD 191612
Walborn, Nolan R.; Howarth, Ian D.; Herrero, Artemio +1 more
The spectrum of HD 191612 has been found to display large, recurrent variations between two highly reproducible, peculiar states; at least four transformations have occurred since 1950. In one state, the spectral type is O6-O7, with C III λ4650 emission comparable to N III λ4640 (the definition of the Of?p category) and P Cygni profiles at He II λ…