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dc.contributor.advisorBogdanovic, Tamara
dc.contributor.authorGe, Qi
dc.date.accessioned2018-05-31T18:13:39Z
dc.date.available2018-05-31T18:13:39Z
dc.date.created2018-05
dc.date.issued2018-03-26
dc.date.submittedMay 2018
dc.identifier.urihttp://hdl.handle.net/1853/59872
dc.description.abstractOne viable seeding mechanism for supermassive black holes is the direct gaseous collapse route in pre-galactic dark matter halos, producing objects on the order of 10^4 - 10^6 solar masses. These events occur when the gas is prevented from cooling below 10^4 K that requires a metal-free and relatively H_2-free medium. The initial collapse cools through atomic hydrogen transitions, but the gas becomes optically thick to the cooling radiation at high densities. We explore the effects of Lyman-alpha trapping in such a collapsing system with a suite of Monte Carlo radiation transport calculations in uniform density and isotropic cases that are based from a cosmological simulation. Our method includes both non-coherent scattering and two-photon line cooling. We find that Lyman-alpha radiation is marginally trapped in the parsec-scale gravitationally unstable central cloud, allowing the temperature to increase to 50,000 K at a number density of 3*10^4 cm^-3 and increasing the Jeans mass by a factor of five. The effective equation of state changes from isothermal at low densities to have an adiabatic index of 4/3 around the temperature maximum and then slowly retreats back to isothermal at higher densities. Our results suggest that Lyman-alpha trapping delays the initial collapse by raising the Jeans mass. Afterward the high density core cools back to 10^4 K that is surrounded by a warm envelope whose inward pressure may alter the fragmentation scales at high densities.
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherGeorgia Institute of Technology
dc.subjectLyman alpha
dc.subjectSMBH formation
dc.titleOn the effect of Lyman alpha trapping during the initial collapse of massive black hole seeds
dc.typeDissertation
dc.description.degreePh.D.
dc.contributor.departmentPhysics
thesis.degree.levelDoctoral
dc.contributor.committeeMemberWise, John
dc.contributor.committeeMemberShoemaker, Deirdre
dc.contributor.committeeMemberBallantyne, David
dc.contributor.committeeMemberVuduc, Richard
dc.date.updated2018-05-31T18:13:39Z


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