PAH processing in space

Leiden Repository

PAH processing in space

Type: Doctoral Thesis
Title: PAH processing in space
Author: Micelotta, Elisabetta Rita
Publisher: Leiden Observatory, Faculty of Science, Leiden University
Issue Date: 2009-11-12
Keywords: Cooling flow
Cosmic rays
Dust
Halos
Intergalactic medium
ISM
Outflows
PAH
Shock waves
Supernova remnants
Abstract: Polycyclic Aromatic Hydrocarbons (PAHs) are one of the most common chemical compounds on Earth. These big molecules are naturally present in crude oil and coal deposits, and are also formed by incomplete combustion of carbon-containing fuels, hence they are found in car exhaust, cigarette smoke and (too) well-cooked meats. This makes PAHs one of the most widespread organic pollutants. In space, PAHs are an important and ubiquitous component of the Interstellar Medium, dominating the mid-infrared emission of many astronomical objects. However, very little is known about the destiny of PAHs when they are bombarded by high-velocity ions and electrons arising from interstellar shocks, hot gas and cosmic rays (CRs). The research described in this thesis shows that in shocks with velocities above 100 km/s and in a million-degree gas, PAHs are completely destroyed by collisions with electrons, and can survive only if isolated in denser clouds. Destruction by CRs is due to collisions with ions. Because of their high energy (5 MeV - 10 GeV) CRs can access these denser clouds and will set the lifetime of those protected PAHs, which can be used as a ‘dye’ for tracing the presence of material entrained in the hot gas.
Description: Promotores: F.P. Israel, A.G.G.M. Tielens, Co-promotor: A.P. Jones
With summary in Dutch
Faculty: Faculteit der Wiskunde en Natuurwetenschappen
Citation: Micelotta, E.R., 2009, Doctoral thesis, Leiden University
Handle: http://hdl.handle.net/1887/14331
 

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application/pdf Chapter 1 Introduction 813.1Kb View/Open
application/pdf Chapter 2 525.3Kb View/Open
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application/pdf Chapter 6 Conclusions and perspectives 97.17Kb View/Open
application/pdf Bibliography 51.68Kb View/Open
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application/pdf Curriculum vitae_Acknowledgements 37.48Kb View/Open
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