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| Identifier |
000410274 |
| Title |
Multiscale study of the structure of molecular clouds : connecting theory with observations |
| Alternative Title |
Μελέτη της δομής των διαστρικών μοριακών νεφών σε διαφορετικές χωρικές κλίμακες: σύγκριση θεωρίας και παρατηρήσεων |
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Author
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Τρίτσης, Άρης Ευάγγελος Δ.
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Thesis advisor
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Τάσσης, Κωνσταντίνος
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Reviewer
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Παυλίδου, Βασιλική
Κυλάφης, Νικόλαος
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| Abstract |
This thesis is a multilateral and multiscale study of the structure of molecular clouds
and the importance of magnetic fields in shaping them. First, we concentrate in the translucent parts of molecular clouds where elongated, quasi-periodic, magnetic-field aligned structures, termed “striations”, have been recently discovered. We perform a series of numerical experiments and we find that striations are formed due to compressible fast magnetosonic waves. Using the properties of these magnetohydrodynamic waves revealed by the presence of striations in an isolated molecular cloud we reconstruct its 3D shape through a normal-mode analysis.
Turning our attention to the smallest, densest parts of molecular clouds we study the relation
between the magnetic field and gas density in contracting prestellar cores. We find that previous studies severely underestimated the observational uncertainties in gas density. By properly accounting for these uncertainties and performing an independent analysis of the projected shapes of cores, we show that the data are in agreement with the predictions of the ambipolar diffusion theory of star formation.
Driven by the need for accurate density estimates we have also performed numerical simulations of collapsing prestellar cores coupled with non-equilibrium chemical modelling and we have developed a method for probing the 3-dimensional shapes of cores using two-dimensional molecular column density maps. Finally, in order to directly compare our numerical models to observations we have developed a state-of-the-art, non local thermodynamic equilibrium (non-LTE) line radiative transfer code.
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| Language |
English |
| Subject |
Interstellar chemistry |
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Line radiative transfer |
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Magnetohydrodynamics |
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Striations |
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Μαγνητοϋδροδυναμική |
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Μεσοαστρική χημεία |
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Μεταφορά διάδοσης ακτινοβολίας ατομικών και μοριακών γραμμών |
| Issue date |
2017-07-10 |
| Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Doctoral theses
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Type of Work--Doctoral theses
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| Views |
1012 |
Multiscale study of the structure of molecular clouds : connecting theory with observations
