Diffuse Interstellar Bands: Physical Conditions That Facilitate the Formation or Preservation of Their Carriers

1998 ◽  
Vol 506 (2) ◽  
pp. 926-926 ◽  
Author(s):  
J. Krełowski ◽  
G. A. Galazutdinov ◽  
F. A. Musaev
Keyword(s):  
Physical Conditions ◽  
Diffuse Interstellar Bands

Diffuse Interstellar Bands: Physical Conditions That Facilitate the Formation or Preservation of Their Carriers

1998 ◽  
Vol 493 (1) ◽  
pp. 217-221 ◽  
Author(s):  
J. Krełowski ◽  
G. A. Galazutdinov ◽  
F. A. Musaev
Keyword(s):  
Physical Conditions ◽  
Diffuse Interstellar Bands

scholarly journals C2 and Diffuse Interstellar Bands

2013 ◽  
Vol 9 (S297) ◽  
pp. 121-124 ◽  
Author(s):  
M. Kaźmierczak ◽  
M. Schmidt ◽  
T. Weselak ◽  
G. Galazutdinov ◽  
J. Krełowski
Keyword(s):  
Interstellar Clouds ◽  
Physical Conditions ◽  
Diffuse Interstellar Bands ◽  
Carbon Molecules ◽  
Long Chain

AbstractC2, the simplest multicarbon molecule is a useful astronomical tool, because the analysis of its lines allows to determine the physical conditions in interstellar clouds. C2 abundances give information about the chemistry of interstellar clouds, especially on the pathway to the formation of long-chain carbon molecules, which may be connected with carriers of diffuse interstellar bands (Douglas 1977, Thorburn et al. 2003). Here we summarize all relations between C2 and diffuse interstellar bands (DIBs).

scholarly journals Diffuse Interstellar Bands: How are they related to known Gas-Phase Constituents of the ISM?

2013 ◽  
Vol 9 (S297) ◽  
pp. 153-162 ◽  
Author(s):  
D. E. Welty
Keyword(s):  
Gas Phase ◽  
Recent Work ◽  
Molecular Species ◽  
Environmental Conditions ◽  
Large Database ◽  
Molecular Absorption ◽  
Regional Variations ◽  
Physical Conditions ◽  
Diffuse Interstellar Bands ◽  
The Mean

AbstractIn this brief review of recent work relating the DIBs to other gas-phase constituents of the ISM, we explore correlations between DIB equivalent widths and the column densities of various atomic and molecular species, drawn from a large database constructed for that purpose. The tightness and slopes of the correlations can provide information on how the DIBs might be related to those species (physically, chemically, spatially) and on various properties of the DIB carriers. Deviations from the mean relationships can reveal dependences of DIB strengths on other parameters, regional variations in DIB behavior, and individual sight lines where unusual environmental conditions affect the DIBs. Variations in DIB profiles (e.g., wings, substructure) and relative strengths may be related to differences in physical conditions inferred from atomic and/or molecular absorption lines.

scholarly journals Diffuse Cloud Models: Successes and Challenges

2013 ◽  
Vol 9 (S297) ◽  
pp. 311-320
Author(s):  
E. Roueff ◽  
M. Ruaud ◽  
F. Le Petit ◽  
B. Godard ◽  
J. Le Bourlot
Keyword(s):  
Radiation Field ◽  
Ionization Rate ◽  
Interstellar Clouds ◽  
Physical Conditions ◽  
Cloud Models ◽  
Diffuse Interstellar Bands ◽  
Molecular Transition ◽  
Diffuse Cloud ◽  
General Physical ◽  
Successes And Challenges

AbstractWe present the general physical conditions thought to be present in diffuse interstellar clouds. The radiation field is driving the atomic to molecular transition and the resulting physical conditions. We focus on the recent observational signatures of significant values of the cosmic ionization rate (10−16 - 10−15 s−1) which should also impact the clues to Diffuse interstellar Bands.

scholarly journals Modern DIB Surveys and DIB Environmental Behavior

2013 ◽  
Vol 9 (S297) ◽  
pp. 13-22 ◽  
Author(s):  
P. Sonnentrucker
Keyword(s):  
Interstellar Medium ◽  
Environmental Behavior ◽  
Research Groups ◽  
Physical Conditions ◽  
The Past ◽  
Diffuse Interstellar Bands

AbstractSince the discovery of the Diffuse Interstellar Bands (DIBs) in the early 1920s, numerous research groups have taken on the task to obtain as complete a census of the DIBs as observationally possible in order to unravel characteristics that would allow the community to tie the DIB carriers to known species. Here, I will briefly review the efforts and progress that were made for the past two decades in producing new, deeper, and more complete DIB surveys. In particular, I will review the important role that these modern surveys are playing in revealing main observational characteristics of the DIBs and their dependence on the local physical conditions in the Galactic Interstellar Medium.

scholarly journals Mapping local interstellar medium with diffuse interstellar bands

2020 ◽  
Vol 495 (2) ◽  
pp. 2035-2052
Author(s):  
Martin Piecka ◽  
Ernst Paunzen
Keyword(s):  
Correlation Coefficients ◽  
Point Of View ◽  
The Other ◽  
Statistical Fluctuation ◽  
Statistical Point ◽  
Physical Conditions ◽  
Diffuse Interstellar Bands ◽  
Colour Excess ◽  
Fluctuation Splitting ◽  
Observational Bias

ABSTRACT With the use of the data from archives, we studied the correlations between the equivalent widths of four diffuse interstellar bands (4430, 5780, 5797, 6284 $\mathring{\rm A}$) and properties of the target stars (colour excess values, distances, and Galactic coordinates). Many different plots of the diffuse interstellar bands and their maps were produced and further analysed. There appears to be a structure in the plot of equivalent widths of 5780  $\mathring{\rm A}$ DIB (and 6284 $\mathring{\rm A}$ DIB) against the Galactic x-coordinate. The structure is well defined below ∼ 150 m$\mathring{\rm A}$ and within |x| < 250 pc, peaking around x = 170 pc. We argue that the origin of this structure is not a statistical fluctuation. Splitting the data in the Galactic longitude into several subregions improve or lower the well-known linear relation between the equivalent widths and the colour excess, which was expected. However, some of the lines of sight display drastically different behaviour. The region within 150° < l < 200° shows scatter in the correlation plots with the colour excess for all of the four bands with correlation coefficients R < 0.58. We suspect that the variation of physical conditions in the nearby molecular clouds could be responsible. Finally, the area 250° < l < 300° displays (from the statistical point of view) significantly lower values of equivalent widths than the other regions – this tells us that there is either a significant underabundance of carriers (when compared with the other regions) or that this has to be a result of an observational bias.

Influence of Magnetic Fields on Solar Hydrodynamics: Experimental Results

1977 ◽  
Vol 36 ◽  
pp. 143-180 ◽  
Author(s):  
J.O. Stenflo
Keyword(s):  
Solar Activity ◽  
Energy Balance ◽  
Magnetic Fields ◽  
Solar Atmosphere ◽  
General Problem ◽  
Solar Rotation ◽  
Active Regions ◽  
Physical Conditions ◽  
Dynamic Phenomena

It is well-known that solar activity is basically caused by the Interaction of magnetic fields with convection and solar rotation, resulting in a great variety of dynamic phenomena, like flares, surges, sunspots, prominences, etc. Many conferences have been devoted to solar activity, including the role of magnetic fields. Similar attention has not been paid to the role of magnetic fields for the overall dynamics and energy balance of the solar atmosphere, related to the general problem of chromospheric and coronal heating. To penetrate this problem we have to focus our attention more on the physical conditions in the ‘quiet’ regions than on the conspicuous phenomena in active regions.

Platelet Aggregation Induced in Vitro by Therapeutic Ultrasound

1977 ◽  
Vol 38 (03) ◽  
pp. 0640-0651 ◽  
Author(s):  
B. V Chater ◽  
A. R Williams
Keyword(s):  
Platelet Aggregation ◽  
Direct Action ◽  
Adenosine Diphosphate ◽  
Ultrasonic Cavitation ◽  
Related Phenomenon ◽  
Release Reaction ◽  
Physical Conditions ◽  
Platelet Aggregates ◽  
Active Substances

SummaryPlatelets were found to aggregate spontaneously when exposed to ultrasound generated by a commercial therapeutic device. At a given frequency, aggregation was found to be a dose-related phenomenon, increasing intensities of ultrasound inducing more extensive and more rapid aggregation. At any single intensity, the extent aggregation was increased as the frequency of the applied ultrasound was decreased (from 3.0 to 0.75 MHz).Ultrasound-induced platelet aggregation was found to be related to overall platelet sensitivity to adenosine diphosphate. More sensitive platelets were found to aggregate spontaneously at lower intensities of sound, and also the maximum extent of aggregation was found to be greater. Examination of ultrasound-induced platelet aggregates by electron microscopy demonstrated that the platelets had undergone the release reaction.The observation that haemoglobin was released from erythrocytes in whole blood irradiated under identical physical conditions suggests that the platelets are being distrupted by ultrasonic cavitation (violent gas/bubble oscillation).It is postulated that overall platelet aggregation is the result of two distinct effects. Firstly, the direct action of ultrasonic cavitation disrupts a small proportion of the platelet population, resulting in the liberation of active substances. These substances produce aggregation, both directly and indirectly by inducing the physiological release reaction in adjacent undamaged platelets.

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