Radiation transport in dense interstellar dust clouds. II - Infrared emission from molecular clouds associated with H II regions

1976 ◽  
Vol 209 ◽  
pp. 75 ◽  
Author(s):  
C. M. Leung
Keyword(s):  
Molecular Clouds ◽  
Interstellar Dust ◽  
Radiation Transport ◽  
Infrared Emission ◽  
H Ii Regions ◽  
Dust Clouds

scholarly journals Grain temperatures and infrared emission from interstellar dust clouds

1977 ◽  
Vol 180 (3) ◽  
pp. 323-337 ◽  
Author(s):  
S. Aiello ◽  
F. Mencaraglia ◽  
A. Blanco ◽  
A. Borghesi ◽  
E. Bussoletti
Keyword(s):  
Interstellar Dust ◽  
Infrared Emission ◽  
Dust Clouds

Extinction Curves, Distances, and Clumpiness of Diffuse Interstellar Dust Clouds

1999 ◽  
Vol 117 (5) ◽  
pp. 2226-2243 ◽  
Author(s):  
Arpad Szomoru ◽  
Puragra Guhathakurta
Keyword(s):  
Interstellar Dust ◽  
Dust Clouds

scholarly journals Discovery of the Carina Flare with NANTEN; Evidence for a Supershell That Triggered the Formation of Stars and Massive Molecular Clouds

1999 ◽  
Vol 51 (6) ◽  
pp. 751-764 ◽  
Author(s):  
Yasuo Fukui ◽  
Toshikazu Onishi ◽  
Rihei Abe ◽  
Akiko Kawamura ◽  
Kengo Tachihara ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Molecular Clouds ◽  
Galactic Plane ◽  
Far Infrared ◽  
Infrared Emission ◽  
High Mass ◽  
Stellar Winds ◽  
Neutral Gas ◽  
Supernova Explosions ◽  
Current Kinetic

Abstract We present extensive observations of the Carina arm region in the 2.6 mm CO (J = 1−0) emission with the NANTEN telescope in Chile. The observations have revealed 120 molecular clouds which are distributed in an area of 283° < l < 293° and 2° .5 < b < 10°. Because of its vertical elongation to the galactic plane, the clouds are named the Carina flare. H I and far-infrared emission show a cavity-like distribution corresponding to the molecular clouds, and soft X-ray emission appears to fill this cavity. It is shown that the Carina flare represents a supershell at a distance of a few kpc that has been produced by about 20 supernova explosions, or equivalent stellar winds of OB stars, over the last ∼ 2×107 yr. The supershell consisting of molecular and atomic neutral gas involves a total mass and kinetic energy of ≳ 3×105M⊙ and ≳ 3×1050 erg, respectively, and the originally injected energy required is about 100-times this current kinetic energy in the shell. It is unique among supershells known previously because of the following aspects: i) it exhibits evidence for the triggered formation of intermediate-to-high-mass stars and massive molecular clouds of 102 − 104M⊙, and ii) the massive molecular clouds formed are located unusually far above the galactic plane at z ∼ 100–500 pc.

scholarly journals Stellar Atmospheres: The Sources of Interstellar Molecules

1973 ◽  
Vol 52 ◽  
pp. 405-412 ◽  
Author(s):  
Mikio Shimizu
Keyword(s):  
Chemical Structure ◽  
Interstellar Dust ◽  
Solar Nebula ◽  
Stellar Atmospheres ◽  
Point Of View ◽  
H Ii Regions ◽  
Interstellar Molecules ◽  
Cometary Nuclei ◽  
Stellar Radiation ◽  
Neutral Clouds

The analysis of the abundance of interstellar molecules in compact H II regions suggests that the molecules are formed in stellar atmospheres (possibly of protostars or of late type stars), transported to the location of the neutral clouds in the cpmpact H II regions, and shielded from decomposition due to stellar radiation by the dust in the clouds. Cometary nuclei and interstellar dust are argued from the astrochemical point of view to be dirty ice of the second kind (or a sort of frozen interstellar molecules). The chemical structure of the primordial solar nebula is discussed under the assumption that long-period comets consist of the most primordial substances of the solar system.

scholarly journals The survival of PAHs and (hydro)carbon nanoparticles in H II regions

2015 ◽  
Vol 11 (A29A) ◽  
Author(s):  
Elisabetta R. Micelotta ◽  
Marco Bocchio ◽  
Aurélie Rémy-Ruyer ◽  
Melanie Köhler ◽  
Nathalie Ysard ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Vibrational Relaxation ◽  
Carbon Nanoparticles ◽  
Infrared Emission ◽  
H Ii Regions ◽  
Destruction Mechanism ◽  
Hydro Carbon ◽  
First Results ◽  
Polycyclic Aromatic ◽  
Physical Response

AbstractObservations show that emission from the Unidentified Infrared (UIR) bands is strongly suppressed in H II regions. UIR bands are generally attributed to vibrational relaxation of FUV - excited Polycyclic Aromatic Hydrocarbon (PAH) molecules or hydrocarbon nanoparticles containing aromatic domains. If the strongly reduced UIR emission in H II regions is due to the suppression of the carriers, an efficient destruction mechanism is required to explain observations. The aim of this work is to clarify whether UV processing of PAHs and nanoparticles is indeed responsible for the observed lack of infrared emission. We present here our first results on the physical response to photo-processing of the proposed UIR-bands carriers.

scholarly journals Correlation of Infrared Emission with H I and CO Gas in the High Latitude Cloud Area L1642

1990 ◽  
Vol 139 ◽  
pp. 216-217
Author(s):  
T. Liljeström ◽  
R. Laureijs
Keyword(s):  
Galactic Plane ◽  
Molecular Data ◽  
Infrared Emission ◽  
Galactic Latitude ◽  
Optical Extinction ◽  
Suitable Candidate ◽  
High Galactic Latitude ◽  
Dust Clouds ◽  
Background Gas ◽  
Co Gas

The high-galactic-latitude cloud L1642 (l = 210.8°, b = −36.7°) is a suitable candidate to relate IR measurements with atomic and molecular data because it has a reasonable size with respect to the rather poor (IRAS) IR resolution, a moderate optical extinction and an isolated location in the direction towards the galactic anticenter. The exceptionally high galactic latitude of −36.7° implies that L1642 is some 60 pc below the galactic plane (if r ≈ 100 pc is adopted for its distance). L1642 is thus sufficiently far off the galactic plane to minimize the confusion by background gas and dust clouds.

scholarly journals Triggered high-mass star formation in the H ii region W 28 A2: A cloud–cloud collision scenario

2020 ◽  
Author(s):  
Katsuhiro Hayashi ◽  
Satoshi Yoshiike ◽  
Rei Enokiya ◽  
Shinji Fujita ◽  
Rin Yamada ◽  
...  
Keyword(s):  
Star Formation ◽  
Intensity Ratio ◽  
Molecular Clouds ◽  
Early Stage ◽  
Infrared Emission ◽  
Radio Continuum ◽  
High Mass ◽  
Continuum Emission ◽  
Mass Star ◽  
H Ii Region

Abstract We report on a study of the high-mass star formation in the H ii region W 28 A2 by investigating the molecular clouds that extend over ∼5–10 pc from the exciting stars using the 12CO and 13CO (J = 1–0) and 12CO (J = 2–1) data taken by NANTEN2 and Mopra observations. These molecular clouds consist of three velocity components with CO intensity peaks at VLSR ∼ −4 km s−1, 9 km s−1, and 16 km s−1. The highest CO intensity is detected at VLSR ∼ 9 km s−1, where the high-mass stars with spectral types O6.5–B0.5 are embedded. We found bridging features connecting these clouds toward the directions of the exciting sources. Comparisons of the gas distributions with the radio continuum emission and 8 μm infrared emission show spatial coincidence/anti-coincidence, suggesting physical associations between the gas and the exciting sources. The 12CO J = 2–1 to 1–0 intensity ratio shows a high value (≳0.8) toward the exciting sources for the −4 km s−1 and +9 km s−1 clouds, possibly due to heating by the high-mass stars, whereas the intensity ratio at the CO intensity peak (VLSR ∼ 9 km s−1) decreases to ∼0.6, suggesting self absorption by the dense gas in the near side of the +9 km s−1 cloud. We found partly complementary gas distributions between the −4 km s−1 and +9 km s−1 clouds, and the −4 km s−1 and +16 km s−1 clouds. The exciting sources are located toward the overlapping region in the −4 km s−1 and +9 km s−1 clouds. Similar gas properties are found in the Galactic massive star clusters RCW 38 and NGC 6334, where an early stage of cloud collision to trigger the star formation is suggested. Based on these results, we discuss the possibility of the formation of high-mass stars in the W 28 A2 region being triggered by cloud–cloud collision.

scholarly journals The Far-Infrared emission of the first (z ∼ 6) massive galaxies

2019 ◽  
Vol 15 (S352) ◽  
pp. 246-247
Author(s):  
George H. Rieke ◽  
Maria Emilia De Rossi ◽  
Irene Shivaei ◽  
Volker Bromm ◽  
Jianwei Lyu
Keyword(s):  
Interstellar Dust ◽  
Far Infrared ◽  
High Energy ◽  
Infrared Emission ◽  
High Energy Density ◽  
Spectral Energy ◽  
Energy Distributions ◽  
Massive Galaxies ◽  
Very High Energy ◽  
Lower Redshift

AbstractThe first massive galaxies (z ∼ 6) have (1) very high energy density due to their small diameters and extreme luminosities in young stars and (2) interstellar dust relatively deficient in carbon compared with silicates. Both of these attributes should raise their interstellar dust temperatures compared with lower redshift galaxies. Not only is this temperature trend observed, but the high-z spectral energy distributions (SEDs) are very broad due to very warm dust. As a result total infrared luminosities – and star formation rates – at the highest redshifts estimated by fitting blackbodies to submm- and mm-wave observations can be low by a factor of ∼2.

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