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 Unidentified Infrared Emission Features

2012 ◽  
Vol 10 (H16) ◽  
pp. 699-700 ◽  
Author(s):  
Christine Joblin
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Infrared Emission ◽  
Interstellar Matter ◽  
Physical Conditions ◽  
Evolutionary Scenario ◽  
Polycyclic Aromatic ◽  
Aromatic Species ◽  
Hydrocarbon Molecules ◽  
Uv Photons ◽  
Ir Bands

AbstractWhen referring to unidentified infrared emission features, one has in mind the series of aromatic IR bands (AIBs) between 3.3 and 15 μm that are observed in emission in many environments where UV photons irradiate interstellar matter. These bands are now used by astronomers to classify objects and characterize local physical conditions. However, a deep analysis cannot proceed without understanding the properties of the band carriers. Large polycyclic aromatic hydrocarbon molecules are attractive candidates but interstellar species are still poorly characterized. Various studies emphasize the need for tackling the link between molecular aromatic species, aliphatic material and very small carbonaceous grains. Other unidentified emission features such as the 6.9, 21 and 30 μm bands could be involved in the evolutionary scenario.

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