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dc.contributor.advisorSchleicher, Dominik
dc.creatorReinoso-Reinoso, Bastián Alejandro
dc.description.abstractIn this work we show how could have been formed intermediate mass black holes in the early Universe through stellar collisions between the first stars of the Universe that formed part of dense stellar clusters. Our work focuses on studying the first star clusters, formed by population III stars which according to recent studies they must have been much more massive and with larger radii, by a factor of 100, than the stars formed in the present day Universe. We also consider the most dense clusters formed with a half-mass radius of 0.1 parsec and gas free, and we follow their evolution with N -body simulations using the code NBODY6 until a time of approximately 2 Million years. The collision between two stars was treated with the hit and stick approximation assuming that all the mass is conserved and that the collision product has the same density that the colliding stars. We did not include stellar evolution nor an initial mass function in our simulations. Our research shows that in such systems there is a contraction of the central part of the cluster by interactions between the stars, which start to merge with a single star in the center of the cluster, forming an object that could contain more than 10% of the total mass of the system. We performed a total of 280 simulations to understand how the number of stars and their size influences the formation and the final mass of the most massive object. Finally we find mathematical relations that allow us to estimate the mass of the object at any time for different combinations of the number of stars and their size in a star cluster of the early Universe, showing that it is possible to form black holes with masses in the order of 1000 Solar Masses within the typical lifetime of population III stars. We also explored the effects of the gas in the clusters and in the process of runaway growth using an analytic and static Plummer potential centered in the cluster, without mass accretion nor gas expulsion. Our results show an increase in the number of collisions and in the mass of the final object, however, we found a delay in the growth of the most massive object related to the difficulties for forming binary systems due to the high velocities of the stars in these systems owing to the extra gravitational force exerted by the potential. Finally we performed the first test simulations with the AMUSE interface, with the objective of coupling in the future a hydrodynamics code to treat the gas in a realistic form in future investigations. We compared the results with the simulations performed with NBODY6 finding an excellent agreement as well as in the clusters evolution as in the formation of massive objects at their center.es_CL
dc.relationinstname: Conicyt
dc.relationreponame: Repositorio Digital RI2.0
dc.rightsAttribution-NonCommercial-ShareAlike 3.0 Chile*
dc.titleN-Body Simulations of Primordial Star Clusters: Formation Pathway for Intermediate Mass Black Holeses_CL
dc.typeTesis Magíster
dc.contributor.institutionUNIVERSIDAD DE CONCEPCIONes_CL
dc.subject.oecd1nCiencias Naturaleses_CL
dc.subject.oecd2nOtras Ciencias Naturaleses_CL

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