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The Three-dimensional Structure of the Warm Local Interstellar Medium. I. Methodology
Redfield, Seth; Wood, Brian E.; Linsky, Jeffrey L. +1 more
In this first in a series of papers, we develop a methodology for constructing three-dimensional models of the local interstellar cloud (LIC) and adjacent warm clouds in the local interstellar medium (LISM). Our models are based on the column density of neutral hydrogen gas (NHI) inferred primarily from measurements of the deuterium col…
ISO-SWS Spectroscopy of NGC 1068
Lutz, D.; Genzel, R.; Sturm, E. +4 more
We present Infrared Space Observatory-Short Wave Spectrometer (ISO-SWS) spectroscopy of NGC 1068 for the complete wavelength range 2.4-45 µm at resolving power ~1500. Selected subranges have been observed at higher sensitivity and full resolving power ~2000. We detect a total of 36 emission lines and derive upper limits for 13 additional tra…
Detection of Dark Matter Concentrations in the Field of Cl 1604+4304 from Weak Lensing Analysis
Umetsu, Keiichi; Futamase, Toshifumi
We present a weak lensing analysis of a region around the galaxy cluster Cl 1604+4304 (z=0.897) on the basis of the deep observations with the Hubble Space Telescope (HST)/Wide Field Planetary Camera 2 (WFPC2). We apply a variant of Schneider's aperture mass technique to the observed WFPC2 field and obtain the distribution of weak lensing signal-t…
A Lyα Bright Jet from a Herbig AE Star
Linsky, J. L.; Bruhweiler, F. C.; Boggess, A. +5 more
We report the detection in Lyα of a collimated, bipolar outflow (HH 409) associated with the 1.5-10 Myr old Herbig Ae star HD 163296. A blueshifted jet is visible in Lyα and Si III extending toward the southwest for at least 6" (725 AU). The combination of low line-of-sight extinction and relative faintness of the central star near Lyα enables us …
Current Helicity of the Large-Scale Photospheric Magnetic Field
Pevtsov, Alexei A.; Latushko, Sergei M.
This paper presents the first results of a study of current helicity of the large-scale magnetic field (LSMF) using full-disk longitudinal Blong magnetograms from the Michelson Doppler Imager on board the SOHO spacecraft. We employ a known technique to reconstruct the vector magnetic field under the assumption of relatively slow evoluti…
Rings in the Planetesimal Disk of β Pictoris
Schultz, A.; Kalas, P.; Larwood, J. +1 more
The nearby main-sequence star β Pictoris is surrounded by an edge-on disk of dust produced by the collisional erosion of larger planetesimals. Here we report the discovery of substructure within the northeast extension of the disk midplane that may represent an asymmetric ring system around β Pic. We present a dynamical model showing that a close …
The Extreme-Ultraviolet Solar Irradiance Spectrum Observed with the Coronal Diagnostic Spectrometer (CDS) on SOHO
Brekke, P.; Thompson, W. T.; Woods, T. N. +1 more
We present a calibrated solar EUV irradiance spectrum in the ranges 307-380 Å and 515-632 Å. The ``Sun as a star'' spectrum was recorded by the Coronal Diagnostic Spectrometer (CDS) on SOHO on 1997 May 15 using the normal incidence spectrometer (NIS) with a spectral resolution between 0.3 and 0.6 Å. The relatively high spectral resolution allows t…
Analysis of a Solar Active Region Extreme-Ultraviolet Spectrum from SERTS-97
Landi, Enrico; Brosius, Jeffrey W.; Thomas, Roger J. +1 more
Goddard Space Flight Center's Solar EUV Research Telescope and Spectrograph was flown on 1997 November 18, carrying an intensified CCD detector and a multilayer-coated toroidal diffraction grating with enhanced sensitivity over that of a standard gold-coated grating throughout the instrument's 299-353 Å spectral bandpass. Spectra and spectroheliog…
Adding More Mysteries to the DA White Dwarf GD 394
Vennes, Stéphane; Christian, Damian J.; Chayer, Pierre +2 more
We present spectroscopic and timing analyses of the hot DA white dwarf GD 394 showing abundance inhomogeneities across its surface. Lick Hamilton echelle, International Ultraviolet Explorer (IUE), HST GHRS, and Hopkins Ultraviolet Telescope (HUT) spectra show dominant Si III and Si IV features, while Extreme Ultraviolet Explorer (EUVE) spectra sho…
Modeling the Variable Chromosphere of α Orionis
Lobel, A.; Dupree, A. K.
A spectral analysis of the prototypical red supergiant star α Ori that is based on near-UV, optical, and near-IR high-dispersion spectra obtained between 1992 September and 1999 July with the Space Telescope Imaging Spectrograph and the Goddard High Resolution Spectrograph on the Hubble Space Telescope, the Utrecht Echelle Spectrograph, and the So…