scholarly journals Ultraviolet absorption by interstellar gas at large distances from the galactic plane

1981 ◽  
Vol 243 ◽  
pp. 460 ◽  
Author(s):  
B. D. Savage ◽  
K. S. de Boer
Keyword(s):  
Galactic Plane ◽  
Ultraviolet Absorption ◽  
Interstellar Gas

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

Ultraviolet absorption by interstellar gas near 30 Doradus

1980 ◽  
Vol 236 ◽  
pp. 769 ◽  
Author(s):  
K. S. de Boer ◽  
J. Koornneef ◽  
B. D. Savage
Keyword(s):  
Ultraviolet Absorption ◽  
Interstellar Gas ◽  
30 Doradus

scholarly journals SN 1006 at optical and UV wavelengths

2006 ◽  
Vol 2 (14) ◽  
pp. 306-306
Author(s):  
Knox S. Long
Keyword(s):  
Optical Properties ◽  
Galactic Plane ◽  
Shock Velocity ◽  
Emission Lines ◽  
Type Ia Supernovae ◽  
Interstellar Gas ◽  
Broad Absorption ◽  
Uv Emission ◽  
Type Ia ◽  
Ia Supernovae

AbstractOptical and UV emission from SN 1006 is observed on the periphery of the SNR, particularly in the NW, and arises as material from interstellar gas is ionized behind the shock front. The shapes of the emission lines have been used to infer a shock velocity of about 2900 km s−1 and to show that the electron and ion temperatures are close to that expected from standard shock theory. The combination of the shock velocity and the proper motion of the filaments in the NE accurately locates SN1006 at a distance of 2.2 kpc, some 550 pc above the Galactic plane. At UV wavelengths, ejecta from SN 1006 have also been observed as broad absorption lines from Si, Ca and Fe in spectra of the Schweitzer-Middleditch star and two quasars. The observations appear to limit the mass of Fe in SN 1006 to less than 0.16 M⊙, much less than expected from models of Type Ia supernovae. In this brief review of the UV and optical properties of SN 1006, I will summarize how these observations yield a fairly consistent description of SN 1006, and suggest what further observations might be undertaken to extend our understanding of SN 1006 in its second millennium.

scholarly journals The High-Latitude Sky at IR, Optical, and UV Wavelengths

1991 ◽  
Vol 144 ◽  
pp. 149-159
Author(s):  
F. X. Désert
Keyword(s):  
High Performance ◽  
Galactic Plane ◽  
Visible Spectrum ◽  
Current Data ◽  
Zodiacal Light ◽  
Interstellar Gas ◽  
Neutral Gas ◽  
Almost All ◽  
Astronomical Satellite ◽  
Fundamental Limitation

We review the current data on the not-so-dark sky covering infrared, visible and ultraviolet wavelengths. Here, we are mainly concerned with the emission from the interstellar gas and dust above and below the galactic plane. Zodiacal light is not discussed in detail and emission from unresolved stars is briefly mentioned. Recent improvements in these studies have been made with the use of new satellite UV data, the use of high-performance CCD in the visible spectrum and extensive analyses from the Infrared Astronomical Satellite (IRAS). We show that cirrus clouds which subtend a large solid angle at high galactic latitudes are made of neutral gas and dust, are within a few hundred parsecs of the Sun, and are almost optically thin up to UV wavelengths. The brightness of these clouds, expressed as vIν = λIλ, is estimated to be within 10–8 and 10–7 W m–2 sr–1 at almost all wavelengths from λ = 0.1 to 300 μm and peaks at 150 μm, for a typical column density of 3 × 1020 H cm–2. They may yield the fundamental limitation to all extragalactic and halo studies.

scholarly journals A (2). Overall Structure: Space Distribution and Motions in the Disk

1955 ◽  
Vol 1 ◽  
pp. 13-24
Keyword(s):  
Large Scale ◽  
Galactic Plane ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Space Distribution ◽  
Interstellar Gas ◽  
Giant Stars ◽  
Galactic System ◽  
Wide Range ◽  
The Common

The population of the disk consists of a great variety of objects with a wide range of concentration towards the galactic plane and of peculiar motions. The extreme population I objects like interstellar gas and dust and super-giant stars, show quite different properties with respect to space distribution and motions, compared to such stars as, for instance, the common G and K giants. The discussions at the conference have concentrated on the observational possibilities of studying the correlation—or the lack of correlation—between the space distributions of different kinds of objects. From recent theoretical as well as observational work it has become apparent that there is a wide range in the ages of the stars contributing to the disk population, from a few million so some 1000 million years. The differences in the distributions of the various kinds of stars very probably must be interpreted in terms of these differences in age and evolution. The most intriguing problem for the present thus seems to be this: Can we trace large-scale structure in the distribution of objects of different ages, and can we derive information on the evolution of the galactic system and of the stars themselves from the degree of resemblance in the large-scale structure exhibited by different objects?

scholarly journals A New High-Resolution Optical Study of Halo Gas

1989 ◽  
Vol 120 ◽  
pp. 442-447
Author(s):  
C. E. Albert ◽  
J. C. Blades ◽  
D. C. Morton ◽  
M. Proulx ◽  
F. J. Lockman
Keyword(s):  
High Resolution ◽  
Galactic Plane ◽  
Optical Study ◽  
Interstellar Gas ◽  
Preliminary Results ◽  
Halo Gas

Abstract:We present preliminary results from a new high resolution optical study of halo gas at the coudé focus of the Canada - France - Hawaii Telescope. Our work is still in progress so two general results are presented here: significant absorption is produced in interstellar gas beyond 500 pc from the galactic plane, and well-resolved halo clouds are identified.

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