The extreme ultraviolet spectrum of G191 - B2B and the ionization of the local interstellar medium

1990 ◽  
Vol 359 ◽  
pp. 499 ◽  
Author(s):  
James Green ◽  
Patrick Jelinsky ◽  
Stuart Bowyer
Keyword(s):  
Interstellar Medium ◽  
Extreme Ultraviolet ◽  
Ultraviolet Spectrum ◽  
Local Interstellar Medium

Extreme ultraviolet observations of G191-B2B and the local interstellar medium with the Hopkins Ultraviolet Telescope

1993 ◽  
Vol 404 ◽  
pp. 663 ◽  
Author(s):  
Randy A. Kimble ◽  
Arthur F. Davidsen ◽  
William P. Blair ◽  
Charles W. Bowers ◽  
W. Van Dyke Dixon ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Extreme Ultraviolet ◽  
Local Interstellar Medium ◽  
Ultraviolet Observations

High-resolution Na I Observations of the Local Interstellar Medium

1991 ◽  
Vol 9 (1) ◽  
pp. 122-123
Author(s):  
Barry Y. Welsh ◽  
Peter W. Vedder ◽  
John V. Vallerga
Keyword(s):  
High Resolution ◽  
Interstellar Medium ◽  
Column Density ◽  
Velocity Structure ◽  
Extreme Ultraviolet ◽  
Sodium Absorption ◽  
Local Interstellar Medium ◽  
Neutral Gas ◽  
Hydrogen Column Density ◽  
Early Type Stars

AbstractWe present high-resolution absorption measurements (R ~ 150 000) of the interstellar Na I D-lines at 5890 Å observed towards 46 early-type stars. The distance to these stars ranges from 20–200 pc, allowing a probe of the local interstellar medium (LISM). The velocity structure, velocity dispersions and column densities of the various cloud components have been derived using an absorption line-fitting analysis. Sodium column densities have been determined for 23 of the 46 target stars. No sodium absorption was detected towards any of the stars with distances < 43 pc. Such null results imply a corresponding hydrogen column density limit, N(H), of ~ 2.5 × 1018cm−2 in many directions in the LISM. For three exceptionally vacant lines of sight (to β CMa, 36 Lyn and η Hya) this limit of low hydrogen column density can be placed out to a much further distance of > 150 pc.We have plotted the distribution of sodium column density in the LISM for a total of 118 stars in the form of three galactic maps. These maps qualitatively show that the present picture of the LISM, in which the first 50 pc is essentially free of dense clumps of neutral gas, is correct. Our map of sodium columns for stars with distances > 100 pc shows that the region within the galactic quadrant defined by 200° < l < 270° shows a conspicuous absence of any significant concentration of neutral gas. This region will be a prime direction of study for forthcoming soft X-ray and extreme ultraviolet satellite experiments.

Measuring EUV Line Emission from the Hot Interstellar Medium

1984 ◽  
Vol 81 ◽  
pp. 348-352
Author(s):  
Simon Labov ◽  
Christopher Martin ◽  
Stuart Bowyer
Keyword(s):  
Interstellar Medium ◽  
Extreme Ultraviolet ◽  
Line Emission ◽  
Grazing Incidence ◽  
Resolving Power ◽  
Sounding Rocket ◽  
Local Interstellar Medium ◽  
Diffuse Emission ◽  
Hot Gas ◽  
Under Construction

AbstractIn the local interstellar medium, the presence of hot gas (log T ~ 5 to 6) has been inferred from measurements of oxygen VI absorption in the ultraviolet, and from diffuse emission in the extreme ultraviolet (EUV) and soft X-ray regions. Here we describe a spectrometer that is very sensitive to gas in this temperature range. The spectrometer uses an array of plane-ruled gratings at grazing incidence in the extreme off plane mount. A set of Kirkpatrick-Baez mirrors focuses the conically diffracted light on to one of two microchannel plate detectors. The field of view of the instrument is 0.2° by 12°. The predicted sensitivity ranges from 50 to 200 ph/(cm2 sec str) with a resolving power (λ/Δλ) of 15 to 50 over the 50 to 700A wavelength band. The instrument is currently under construction for a sounding rocket flight.

Kinematical Structure of the Local Interstellar Medium: The Galactic Center Hemisphere

1997 ◽  
Vol 484 (2) ◽  
pp. 761-778 ◽  
Author(s):  
Ricardo Genova ◽  
John E. Beckman ◽  
Stuart Bowyer ◽  
Thomas Spicer
Keyword(s):  
Interstellar Medium ◽  
Galactic Center ◽  
Local Interstellar Medium
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