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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

Physically Modeling High-Redshift Ultraluminous Infrared Galaxies

Hayward, Christopher 02 January 2013 (has links)
We have used a combination of hydrodynamical simulations, dust radiative transfer, and an empirically based analytical model for galaxy number densities and merger rates in order to physically model the bright high-redshift submillimeter-selected galaxy (SMG) population. We report the results of three projects: In the first we study the dependence of a galaxy’s observed-frame submillimeter (submm) flux on its physical properties. One of our principal conclusions is that the submm flux scales significantly more weakly with star formation rate for starbursts than for quiescently star-forming galaxies. Consequently, we argue that the SMG population is not exclusively merger-induced starbursts but rather a mix of merger-induced starbursts, early-stage mergers where two quiescently star-forming disk galaxies are blended into one submm source ("galaxy-pair SMGs"), and isolated disk galaxies. In the second work we present testable predictions of this model by demonstrating how quiescently star-forming and starburst SMGs can be distinguished from integrated data alone. Starbursts tend to have higher luminosity, effective dust temperature, global star formation efficiency \((L_{IR}/M_{gas})\), and infrared excess \((L_{IR}/L_{FUV})\) and tend to lie significantly above the star formation rate-stellar mass relation defined by quiescently star-forming galaxies. These diagnostics can be used to observationally determine the relative contribution of quiescently star-forming and starburst galaxies to the SMG population. In the final work we present the SMG number density, cumulative number counts, and redshift distribution predicted by our model. We show that, contrary to previous claims, the observed SMG number counts do not provide evidence for a top-heavy initial mass function. We also show that starbursts and galaxy-pair SMGs both contribute significantly to the bright SMG counts, whereas isolated disks contribute significantly only at the faint end. / Astronomy
262

A study of the gamma ray production from extragalactic objects

劉美楣, Lau, Mei-mei. January 1987 (has links)
published_or_final_version / Physics / Master / Master of Philosophy
263

A study of diffuse galactic gamma radiation

吳子皎, Ng, Tze-kau. January 1989 (has links)
published_or_final_version / Physics / Master / Master of Philosophy
264

A study of the large-scale distribution of gamma-rays in the galaxy

潘昭邦, Poon, Chiu-bong, Edward. January 1983 (has links)
published_or_final_version / Physics / Doctoral / Doctor of Philosophy
265

The origin of extragalactic gamma rays

余君岳, Yu, Kwan-ngok, Peter. January 1988 (has links)
published_or_final_version / Physics / Doctoral / Doctor of Philosophy
266

PHYSICAL PROCESSES ASSOCIATED WITH THE INFRARED-MILLIMETER COMPONENT OF THE SPECTRA FROM THE NUCLEI OF SEYFERT GALAXIES

Fogarty, William George, 1942- January 1972 (has links)
No description available.
267

GALAXY ANGULAR MOMENTUM

Thompson, Laird Alan, 1947- January 1974 (has links)
No description available.
268

THE NATURE OF HEAVY-ELEMENT ABUNDANCE GRADIENTS IN GALAXIES

Jensen, Eric Bruce, 1948- January 1977 (has links)
No description available.
269

The evolution of radio galaxies

Longair, M. S. January 1967 (has links)
No description available.
270

Constraining galaxy-cluster masses with multi-waveband observations

Olamaie, Malak January 2012 (has links)
No description available.

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