Doctoral theses

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Identifier	uch.physics.phd//1995paulakis
Title	Theoretical study of OH MASERS in star-forming regions
Alternative Title	Θεωρητική μελέτη των MASER OH που δημιουργούνται στις περιοχές γέννησης αστεριών
Author	Παυλάκης, Κωνσταντίνος Γ
Thesis advisor	Κυλάφης, Νικόλαος
Abstract	In this thesis, a systematic study of oh maser pumping in star-forming regions has been undertaken aiming at the inversion of oh maser problem, i.e. the extraction of information about the physical conditions in star-forming regions, from the maser observations. Due to lack of the appropriate formalism, i have generalized the Sobolev or large velocity gradient method for solving radiative transefer problems in moving media to treat spectral lines that overlap locally or non-locally. When line overlap effects are present, the computation of the photon transport is more complicated because as the photons from one line propagate in the medium, they can be absorbed by the other line. I have derived expressions for both the intensity and the mean intensity of the radiation when local or non-local overlap effects are present. The study of oh maser pumping in star-forming regions has been done by adding one pumping mechanism at a time.These are : collisions, local line overlap, non-local line overlap and external infrared radiation field. Collision rates of oh with ortho- and para-H2 have been used and it has been found that it makes a qualitative difference whether the oh molecules collide with para-H2 or ortho-H2. Thus, maser observations may reveal the fractional abundance of ortho-H2 in star-forming regions.
Language	English
Issue date	1995-04-10
Collection	School/Department--School of Sciences and Engineering--Department of Physics--Doctoral theses
	Type of Work--Doctoral theses
Permanent Link	https://elocus.lib.uoc.gr//dlib/b/e/e/metadata-dlib-1995DIS0158.tkl
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