LARGE SCALE GALACTIC SHOCKS AND MOTIONS OF THE CLOUD MEDIUM.
Item
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Title
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LARGE SCALE GALACTIC SHOCKS AND MOTIONS OF THE CLOUD MEDIUM.
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Identifier
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AAI8312384
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identifier
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8312384
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Creator
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WANG, CHAO-YEA R.
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Contributor
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Prof. Chi Yuan
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Date
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1983
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Language
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English
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Publisher
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City University of New York.
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Subject
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Physics, Astronomy and Astrophysics
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Abstract
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Quasi-steady flows of the interstellar gas in a spiral gravitational field are studied for the purpose of further understanding galactic shock, interstellar clouds, and star formation in the post shock regions.;Qualitatively, we closely follow the two-phase model explored by Shu et al. (1972). Moreover, we extend the field of investigation to the cloud phase in the post shock regions, especially where the star formation and cloud-cloud collisions are prominent. The problem also includes the velocity difference between the cloud and the intercloud phases behind the shock front. We demonstrate that the drag force between the cloud and the intercloud phase is far from sufficient enough to bring them to co-move within a reasonable distance behind the shock front. We then further study the behavior of the cloud-cloud collision and conclude that the cloud-cloud collision is the major mechanism that slows down the velocity of clouds in the post shock regions within approximately 100pc behind the shock front.;We also determine the structure of the shock layer of the cloud medium. The kinematic turbulence viscosity is assumed to be equal to the product of the mean free path of the cloud-cloud collision and the mean turbulence speed of clouds.;By adopting the equation of state of the interstellar gas, we can carry out a detailed study of Quasi-steady flows of interstellar gas including phase transition. Our results are in good agreement with the results of Shu et al. (1972). In 1976 De Jong proposed that in addition to the low-energy cosmic rays, photoelectric heating is a major heating source for the interstellar gas. He then determined the equation of state for the interstellar gas that is in better agreement with existing observations.;We use De Jong's equation of state for the interstellar gas and repeat similar calculations to those done by Shu et al. (1972). Our results again agree with Shu et al. (1972).
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Physics
