scholarly journals DIVISION VI: INTERSTELLAR MATTER

2007 ◽  
Vol 3 (T26B) ◽  
pp. 173-173
Author(s):  
John Dyson ◽  
Thomas J. Millar ◽  
Bo Reipurth ◽  
You-Hua Chu ◽  
Gary J. Ferland ◽  
...  
Keyword(s):  
Molecular Clouds ◽  
Interstellar Matter ◽  
Ionized Gas ◽  
Diffuse Matter

Division VI gathers astronomers studying the diffuse matter in space between stars, ranging from primordial intergalactic clouds, via dust and neutral and ionized gas in galaxies, to the densest molecular clouds and the processes by which stars are formed.

scholarly journals Division VI: Interstellar Matter

2001 ◽  
Vol 24 (2) ◽  
pp. 191-191
Keyword(s):  
Molecular Clouds ◽  
Interstellar Matter ◽  
Diffuse Matter

Division VI gathers astronomers studying the diffuse matter in space between the stars, ranging from primordial intergalactic clouds via dust and neutral and ionised gas in galaxies to the densest molecular clouds and the processes by which stars are formed.

scholarly journals DIVISION VII: THE GALACTIC SYSTEM

2008 ◽  
Vol 4 (T27A) ◽  
pp. 273-274
Author(s):  
Ortwin Gerhard ◽  
Despina Hatzidimitriou ◽  
Patricia A. Whitelock ◽  
Charles J. Lada ◽  
Ata Sarajedini ◽  
...  
Keyword(s):  
Molecular Clouds ◽  
Ionized Gas ◽  
Galactic System ◽  
Diffuse Matter

Division VII gathers astronomers studying the diffuse matter in space between stars, ranging from primordial intergalactic clouds, via dust and neutral and ionized gas in galaxies, to the densest molecular clouds and the processes by which stars are formed.

scholarly journals Molecular and ionized gas kinematics in the GC Radio Arc

2016 ◽  
Vol 11 (S322) ◽  
pp. 133-136
Author(s):  
N. Butterfield ◽  
C.C. Lang ◽  
E. A. C. Mills ◽  
D. Ludovici ◽  
J. Ott ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Cloud ◽  
Molecular Clouds ◽  
Radio Continuum ◽  
Molecular Gas ◽  
The South ◽  
Ionized Gas ◽  
Molecular Emission ◽  
Gas Kinematics

AbstractWe present NH3 and H64α+H63α VLA observations of the Radio Arc region, including the M0.20 – 0.033 and G0.10 – 0.08 molecular clouds. These observations suggest the two velocity components of M0.20 – 0.033 are physically connected in the south. Additional ATCA observations suggest this connection is due to an expanding shell in the molecular gas, with the centroid located near the Quintuplet cluster. The G0.10 – 0.08 molecular cloud has little radio continuum, strong molecular emission, and abundant CH3OH masers, similar to a nearby molecular cloud with no star formation: M0.25+0.01. These features detected in G0.10 – 0.08 suggest dense molecular gas with no signs of current star formation.

scholarly journals An extensive study of interstellar matter in the IC 1396 region using several molecular lines and transitions of CO and far-infrared maps from IRAS

1991 ◽  
Vol 147 ◽  
pp. 513-514
Author(s):  
H. Weikard ◽  
K. Sugitani ◽  
G. Duvert ◽  
M. Miller
Keyword(s):  
Molecular Clouds ◽  
Far Infrared ◽  
Extensive Study ◽  
Interstellar Matter ◽  
Molecular Lines ◽  
H Ii Region

IC 1396 is an H II region in Cepheus excited by the massive 06.5 star HD 206267. The distance is about 750 pc. The region exhibits a number of bright-rimmed molecular clouds in which outflows have been detected (Sugitani et al. 1989, Duvert et al. 1990).

scholarly journals Division VI: Interstellar Matter

2005 ◽  
Vol 1 (T26A) ◽  
pp. 267-271
Author(s):  
John Dyson ◽  
Tom Millar ◽  
You-Hua Chu ◽  
Gary Ferland ◽  
Pepe Franco ◽  
...  
Keyword(s):  
Observational Studies ◽  
Interstellar Matter ◽  
Molecular Physics ◽  
Radiative Processes ◽  
The Past ◽  
Evolved Stars ◽  
Working Groups ◽  
Key Aspects ◽  
Physical And Chemical ◽  
Diffuse Matter

Commission 34 covers diffuse matter in space on scales ranging from the circumstellar to the galactic and intergalactic. As such it has enormous scope and because of this, it alone forms Division VI. Key aspects include star formation, matter around evolved stars, astrochemistry, nebulae, galactic and intergalactic clouds and the multitude of effects of the interaction of stars with their surroundings. Associated with these areas are a huge range of physical and chemical processes including hydrodynamics and magnetohydrodynamics, radiative processes, molecular physics and chemistry, plasma processes and others too numerous to name. These are complemented by an equally huge range of observational studies using practically all space and ground-based instrumentation at nearly all observable wavelengths. A glance at any data-base of publications over the past few years attests to the vigorous state of these studies. The current membership of the Division is around 800. It also has three separate working groups.

scholarly journals Interstellar Matter with Very Large Telescopes

1984 ◽  
Vol 79 ◽  
pp. 675-678
Author(s):  
J. Lequeux
Keyword(s):  
High Resolution ◽  
Absorption Lines ◽  
High Resolution Spectroscopy ◽  
Interstellar Matter ◽  
Large Telescope ◽  
Interstellar Absorption ◽  
Near Ir ◽  
Very Large Telescope ◽  
Large Telescopes ◽  
Diffuse Matter

Interstellar matter is certainly one of the fields where a very large telescope (VLT) will prove to be most fruitful. This includes (somewhat paradoxically, but this will be explained later) the study of extended emissions. I will now examine in turn the different domains of interest for a VLT.I. Neutral diffuse matterOptical and near IR observations will mainly contribute to this domain through high-resolution spectroscopy of interstellar absorption lines in the spectra of stars. These lines are resonant lines of atoms (NaI, KI, etc.) or ions (CaII, TiII, etc.) as well as of some molecules (CH+, CH, CN, CS+, C2 in the near IR). Clearly this kind of study is always photon - limited; a VLT will collect more photons than present telescopes, thus increase the possibilities considerably.

scholarly journals Ionized Disk/Halo Gas: Insight from Optical Emission Lines and Pulsar Dispersion Measures

1991 ◽  
Vol 144 ◽  
pp. 67-76
Author(s):  
R. J. Reynolds
Keyword(s):  
Galactic Disk ◽  
Large Fraction ◽  
Optical Emission ◽  
Interstellar Matter ◽  
Power Budget ◽  
Ionized Gas ◽  
Lyman Continuum ◽  
Dominant State ◽  
Dispersion Measures ◽  
Halo Gas

Warm (≈ 104 K), diffuse H+ is a significant component of the interstellar medium within the Galactic disk and lower halo. This gas accounts for about one quarter of the interstellar atomic hydrogen, consumes a large fraction of the interstellar power budget, and appears to be the dominant state of interstellar matter 1 kpc above the midplane. The origin of this ionized gas is not yet established; however, of the known sources of ionization only 0 stars and perhaps supernovae produce enough power to balance the “cooling” rate of the gas. If 0 stars are the source of the ionization, then the interstellar HI, including the extended “Lockman layer”, must have a morphology that allows about 14% of the Lyman continuum photons emitted by the stars to travel hundreds of parsecs within the Galactic disk and up into the lower halo.

scholarly journals Tidally-disrupted Molecular Clouds falling to the Galactic Center

2016 ◽  
Vol 11 (S322) ◽  
pp. 115-118 ◽  
Author(s):  
Masato Tsuboi ◽  
Yoshimi Kitamura ◽  
Kenta Uehara ◽  
Ryosuke Miyawaki ◽  
Atsushi Miyazaki
Keyword(s):  
Molecular Cloud ◽  
Molecular Clouds ◽  
Galactic Center ◽  
Outer Region ◽  
Recombination Line ◽  
Ionized Gas ◽  
Boundary Area ◽  
Gas Streams ◽  
Uv Emission ◽  
Sgr A

AbstractWe found a molecular cloud connecting from the outer region to the “Galactic Center Mini-spiral (GCMS)” which is a bundle of the ionized gas streams adjacent to Sgr A*. The molecular cloud has a filamentary appearance which is prominent in the CSJ=2-1 emission line and is continuously connected with the GCMS. The velocity of the molecular cloud is also continuously connected with that of the ionized gas in the GCMS observed in the H42α recombination line. The morphological and kinematic relations suggest that the molecular cloud is falling from the outer region to the vicinity of Sgr A*, being disrupted by the tidal shear of Sgr A* and ionized by UV emission from the Central Cluster. We also found the SiOJ=2-1 emission in the boundary area between the filamentary molecular cloud and the GCMS. There seems to exist shocked gas in the boundary area.

scholarly journals Variations in the abundance of small particles

1991 ◽  
Vol 147 ◽  
pp. 151-160
Author(s):  
F. Boulanger
Keyword(s):  
Gas Phase ◽  
Large Amplitude ◽  
Molecular Clouds ◽  
Velocity Structure ◽  
Size Range ◽  
Interstellar Matter ◽  
Dust Grains ◽  
Small Particles ◽  
Order Of Magnitude ◽  
Ir Emission

IRAS images of nearby molecular clouds show that the mid-IR emission from small particles in the size range 102 to 105 atoms is distributed very differently from the 100 μm emission from large dust grains. Variations in color ratios by as much as one order of magnitude are seen on all angular scales. We summarize observational properties of the color variations and argue that neither their large amplitude nor their morphology can be explained by changes of the excitation by the UV radiation field only. The color variations reflect considerable inhomogeneities in the abundance of small particles. We suggest that the abundance variations are related to the cycling of interstellar matter between the gas phase and dust grains. This interpretation entails that clouds with distinct IR colors differ in their density and velocity structure and that cycling of matter between gas phase and dust grains is more ubiquitous and rapid that generally thought.

scholarly journals Abundances and Chemical Evolution of the Galactic Center

1977 ◽  
Vol 45 ◽  
pp. 79-101
Author(s):  
Jean Audouze
Keyword(s):  
Chemical Evolution ◽  
Gamma Rays ◽  
Molecular Clouds ◽  
Galactic Center ◽  
Solar Neighbourhood ◽  
Interstellar Matter ◽  
Low Mass Stars ◽  
Element Abundances ◽  
The Galaxy ◽  
Low Mass

AbstractFrom observations of the galactic center using various techniques radioastronomy, millimeter waves (molecules) – infrared and gamma rays, the interstellar matter of this region* appears to have been strongly processed into stars : the gas density is much lower than in the solar neighbourhood. From CO measurements one knows that there are many molecular clouds such as SgrB2 where stars are forming now. From IR measurements, there are some indication that low mass stars are relatively more numerous in such regions than in the external regions of the galaxy. Finally the heavy element abundances show three important features (i) the possibility of strong enhancements in elements such as N and in a less extent 0 and Ne (the so called abundance gradients), (ii) Some specific enhancements of isotopes such43C,44N and also47O relative to42C,45N and43O (iii) Deuterium seems to have a lower abundance than in other parts of the galaxy such as the solar neighbourhood. Simple models of chemical evolution have been designed to account for such features and are rewiewed here.

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