scholarly journals Dust distribution and temperature in the Magellanic Clouds interstellar medium

1991 ◽  
Vol 148 ◽  
pp. 407-414 ◽  
Author(s):  
M. Sauvage ◽  
L. Vigroux
Keyword(s):  
Interstellar Dust ◽  
Hubble Space Telescope ◽  
Infrared Emission ◽  
Magellanic Clouds ◽  
Infrared Space Observatory ◽  
Chemical Abundances ◽  
The Galaxy ◽  
Recent Developments ◽  
Dust Composition ◽  
Dust Distribution

This review deals with the various aspects of interstellar dust in the Magellanic Clouds (MCs). Dust properties can be traced from interstellar absorption, with an emphasis on UV properties, and from infrared emission. Thanks to IRAS, most of the recent developments in this field have been found in the infrared. The low resolution of IRAS was, in fact, well suited for MC mapping and these observations offer a unique opportunity to study the dust properties in various conditions of the Interstellar Radiation Field (ISRF) and of chemical abundances. The proximity of the MCs allows a direct study of the link between the stellar population and the dust properties via the ISRF. On the other hand, the comparison of IRAS data in the MCs and in the Galaxy allows us to study the dust composition for metallicity varying by a factor of 10. From these data and the previous results on UV absorption, it emerges that if the gas-to-dust ratio changes with metallicity, there is also a variation in the relative abundances of the dust components. In this review, we will also discuss how our knowledge of the MCs will be used to prepare for observations of more distant galaxies, with the next generation of space observatories such as the Hubble Space Telescope and the Infrared Space Observatory.

ERE from Graphene Oxide in the ISM. A possible link to IOM?

2020 ◽  
Author(s):  
Peter Sarre
Keyword(s):  
Graphene Oxide ◽  
Organic Material ◽  
Interstellar Dust ◽  
Emission Spectra ◽  
Optical Emission ◽  
Interplanetary Dust ◽  
Infrared Emission ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
Infrared Space Observatory

<p>Dust particles play a major role in the formation, evolution and chemistry of interstellar clouds, stars, and planetary systems. Commonly identified forms include amorphous and crystalline carbon-rich particles and silicates. Also present in many astrophysical environments are polycyclic aromatic hydrocarbons (PAHs), detected through their infrared emission, and which are essentially small flakes of graphene. Astronomical observations over the past four decades have revealed a widespread unassigned ‘extended red emission’ (ERE) feature which is attributed to luminescence of dust grains. A luminescence feature with similar characteristics to ERE has been found in organic material in interplanetary dust particles and carbonaceous chondrites.  </p> <p>There is a strong similarity between laboratory optical emission spectra of graphene oxide (GO) and ERE, leading to this proposal that emission from GO nanoparticles is the origin of ERE and that heteroatom-containing PAH structures are a significant component of interstellar dust. The proposal is supported by infrared emission features detected by the <em>Infrared Space Observatory (ISO)</em> and the <em>Spitzer Space Telescope</em>.  </p> <p>Insoluble Organic Material (IOM) has a chemical structure with some similarities to graphene oxide.  It is suggested this may contribute to the discussion as to whether IOM has an origin in the interstellar medium or the solar nebula, or some combination.</p>

Chemical Abundances and Isotope Ratios in Molecular Clouds

1996 ◽  
Vol 13 (2) ◽  
pp. 202-203
Author(s):  
M. R. Hunt
Keyword(s):  
Observational Data ◽  
Molecular Clouds ◽  
Isotope Ratios ◽  
Magellanic Clouds ◽  
Chemical Abundances ◽  
Millimetre Wave ◽  
The Galaxy ◽  
Molecular Abundances

AbstractA program to observe millimetre-wave molecular transitions in a number of southern-sky molecular clouds is under way. Molecular clouds in both the Galaxy and the Magellanic Clouds are included in the sample. The aim of the program is to build a body of observational data which can be used to derive molecular abundances in southern-sky molecular clouds.

scholarly journals Graphene oxide nanoparticles in the interstellar medium

2019 ◽  
Vol 490 (1) ◽  
pp. L17-L20 ◽  
Author(s):  
P J Sarre
Keyword(s):  
Graphene Oxide ◽  
Interstellar Dust ◽  
Emission Spectra ◽  
Optical Emission ◽  
Infrared Emission ◽  
Dust Particles ◽  
Infrared Space Observatory ◽  
Interstellar Clouds ◽  
General Acceptance ◽  
Extended Red Emission

ABSTRACT Dust particles play a major role in the formation, evolution and chemistry of interstellar clouds, stars, and planetary systems. Commonly identified forms include amorphous and crystalline carbon-rich particles and silicates. Also present in many astrophysical environments are polycyclic aromatic hydrocarbons (PAHs), detected through their infrared emission, and which are essentially small flakes of graphene. Astronomical observations over the past four decades have revealed a widespread unassigned ‘extended red emission’ (ERE) feature which is attributed to luminescence of dust grains. Numerous potential carriers for ERE have been proposed but none has gained general acceptance. In this Letter it is shown that there is a strong similarity between laboratory optical emission spectra of graphene oxide (GO) and ERE, leading to this proposal that emission from GO nanoparticles is the origin of ERE and that these are a significant component of interstellar dust. The proposal is supported by infrared emission features detected by the Infrared Space Observatory (ISO) and the Spitzer Space Telescope.

scholarly journals The 3-Dimensional Distribution of Interstellar Dust

2013 ◽  
Vol 9 (S298) ◽  
pp. 213-220
Author(s):  
Jayant Murthy
Keyword(s):  
Interstellar Dust ◽  
Three Dimensional ◽  
3 Dimensional ◽  
Dust Extinction ◽  
Structure And Morphology ◽  
Current State ◽  
The Galaxy ◽  
Dimensional Distribution ◽  
Color Data ◽  
Dust Distribution

AbstractA knowledge of the three dimensional distribution of interstellar dust is critical in interpreting all observations of the sky, particularly in the understanding of the structure and morphology of our Galaxy. It has been much easier to map the integrated dust extinction through the Galaxy, which is needed in modeling extragalactic sources, but this yields an overestimate of reddening to Galactic objects. Massive surveys, such as Gaia, present both a problem in that the distribution of interstellar dust must be known in order to model the internal structure of the Galaxy and an opportunity in that multi-color data may be used to deconvolve the dust distribution. I will present the current state of the modeling, which is yet in its early stages.

scholarly journals Infrared Emission from Dust in Supernovae and Supernova Remnants

1989 ◽  
Vol 135 ◽  
pp. 479-486
Author(s):  
Eli Dwek
Keyword(s):  
Supernova Remnants ◽  
Interstellar Dust ◽  
Infrared Emission ◽  
Dust Particles ◽  
Actual Process ◽  
Supernovae And Supernova Remnants ◽  
Infrared Observations ◽  
Interstellar Dust Grains ◽  
The Galaxy ◽  
Astronomical Satellite

The need to replenish the reservoir of interstellar dust grains that are continuously being destroyed in the interstellar medium, and the presence of isotopic anomalies in meteorites, suggest that supernovae may be important sources of interstellar dust. Infrared observations of supernovae or their unmixed ejecta may provide the first direct evidence for newly-formed grains in this environment. The recently discovered supernova, SN 1987A, currently offers the best prospects for observing the actual process of dust formation in a supernova.In contrast, supernova remnants constitute the most important grain destruction mechanism in the galaxy. Interstellar dust swept up by the expanding blast wave is predominantly heated and destroyed by collisions with a shocked x-ray emitting plasma. Infrared observations of remnants can therefore provide valuable information on the interaction between dust particles and a hot gas. This interaction can best be studied in supernova remnants detected with the Infrared Astronomical Satellite (IRAS). This paper reviews what we have learned so far on the subjects of grain formation and destruction by studying the infrared emission from supernovae and supernova remnants.

scholarly journals Interstellar Dust in the LMC

1984 ◽  
Vol 108 ◽  
pp. 403-404
Author(s):  
Geoffrey C. Clayton ◽  
Peter G. Martin
Keyword(s):  
Interstellar Dust ◽  
Magellanic Clouds ◽  
Dust Formation ◽  
Infrared Photometry ◽  
The Galaxy ◽  
Ultraviolet Extinction ◽  
Formation Efficiency

New IUE observations confirm the differences between the Galactic and LMC ultraviolet extinction curves and show some evidence for variations within the LMC. Visual and infrared photometry and polarimetry show that the anomalous properties of the LMC dust do not extend to longer wavelengths. Despite the much different dust to gas ratios in the Galaxy and the Magellanic clouds, the dust formation efficiency is similar when the abundances are included.

scholarly journals Interstellar Extinction in the Magellanic Clouds

1984 ◽  
Vol 108 ◽  
pp. 341-351
Author(s):  
K. Nandy
Keyword(s):  
Interstellar Dust ◽  
Interstellar Extinction ◽  
Magellanic Clouds ◽  
Absorption Feature ◽  
Early Type ◽  
Distribution Law ◽  
Broad Absorption ◽  
Grain Sizes ◽  
The Galaxy ◽  
The Difference

The extinction properties of interstellar dust in the Large and Small Magellanic Clouds have been systematically investigated, using recent UV observations of early type Cloud members along with complementary visible data. The extinction curves differ systematically from the standard Galactic curve. The latter shows a broad absorption feature centred near 2200Å in virtually all sight lines but this is absent or only weakly present in the SMC; also the SMC extinction in the far UV is the largest known relative to EB-V. Dust in the LMC appears to be intermediate in extinction properties between the SMC and normal Galactic material. However, exceptions from the average extinction curves have been found in both Clouds.Model computations show that the range of grain sizes and their number distribution law may not be significantly different in the Clouds and the Galaxy; the difference in extinction laws can be accounted for by varying the graphite contribution relative to silicate.

scholarly journals DIBs, Interstellar Dust, and Extinction

2013 ◽  
Vol 9 (S297) ◽  
pp. 147-152 ◽  
Author(s):  
G. C. Clayton
Keyword(s):  
Interstellar Medium ◽  
Interstellar Dust ◽  
Dust Grains ◽  
Weak Correlation ◽  
Interstellar Clouds ◽  
The Galaxy ◽  
The Relationship

AbstractThe relationship between DIBs and dust is still unknown. The correlation between reddening and DIB strength means that the DIBs are mixed in with the dust and gas in interstellar clouds. The DIBs are relatively stronger in the diffuse interstellar medium than in dense clouds. There is only a weak correlation between the DIBs and the UV extinction parameters including the 2175 Å bump strength and the far-UV rise. In addition, the bump dust grains are sometimes polarized, while the DIBs are not. However, observations of DIBs in the SMC show that when the 2175 Å bump is weak or missing so are the DIBs. Two of the four sightlines that deviate strongly from the CCM UV extinction in the Galaxy show weak DIBs.

scholarly journals Populations of OB-type stars in galaxies

2010 ◽  
Vol 6 (S272) ◽  
pp. 233-241
Author(s):  
Christopher J. Evans
Keyword(s):  
Stellar Evolution ◽  
Massive Stars ◽  
Spectral Synthesis ◽  
High Redshift ◽  
Young Star ◽  
Magellanic Clouds ◽  
Star Forming ◽  
The Galaxy ◽  
External Galaxies

AbstractOne of the challenges for stellar astrophysics is to reach the point at which we can undertake reliable spectral synthesis of unresolved populations in young, star-forming galaxies at high redshift. Here I summarise recent studies of massive stars in the Galaxy and Magellanic Clouds, which span a range of metallicities commensurate with those in high-redshift systems, thus providing an excellent laboratory in which to study the role of environment on stellar evolution. I also give an overview of observations of luminous supergiants in external galaxies out to a remarkable 6.7 Mpc, in which we can exploit our understanding of stellar evolution to study the chemistry and dynamics of the host systems.

scholarly journals The properties of early-type stars in the Magellanic Clouds

2008 ◽  
Vol 4 (S256) ◽  
pp. 325-336
Author(s):  
Christopher J. Evans
Keyword(s):  
Physical Properties ◽  
Mass Loss ◽  
Temperature Scale ◽  
Massive Stars ◽  
Magellanic Clouds ◽  
Early Type ◽  
The Past ◽  
The Galaxy ◽  
Stellar Temperature ◽  
Early Type Stars

AbstractThe past decade has witnessed impressive progress in our understanding of the physical properties of massive stars in the Magellanic Clouds, and how they compare to their cousins in the Galaxy. I summarise new results in this field, including evidence for reduced mass-loss rates and faster stellar rotational velocities in the Clouds, and their present-day compositions. I also discuss the stellar temperature scale, emphasizing its dependence on metallicity across the entire upper-part of the Hertzsprung-Russell diagram.

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