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dc.contributor.advisorBonnell, Ian Alexander
dc.contributor.authorPetkova, Maya Atanasova
dc.coverage.spatialix, 137, [13] p.en_US
dc.description.abstractIonising radiation is present in a variety of astrophysical problems, and it is particularly important for shaping the process of star formation in molecular clouds, containing hot, high-mass stars. In order to account for the effects of ionising radiation within numerical models of star formation, we need to combine a hydrodynamics method with a radiative transfer method and obtain a radiation hydrodynamics scheme (RHD). In this thesis I achieve live radiation hydrodynamics by coupling the Smoothed Particle Hydrodynamics (SPH) code Phantom with the Monte Carlo Radiative Transfer (MCRT) code CMacIonize. Since SPH is particle-based and MCRT is grid-based, I construct an unstructured, Voronoi grid in order to establish a link between the two codes. In areas with large density gradients, a Voronoi grid based purely on the SPH particle positions achieves insufficient resolution, and therefore I propose a novel algorithm for inserting a small number of additional grid cells to improve the local resolution. Furthermore, the MCRT calculations require the knowledge of an average density for each Voronoi cell. To address this, I develop an analytic density mapping from SPH to a Voronoi grid, by deriving an expression for the integrals of a series of kernel functions over the volume of a random polyhedron. Finally, I demonstrate the validity of the live RHD through the benchmark test of D-type expansion of an H II region, where good agreement is shown with the existing literature. The RHD implementation is then used to perform a proof-of-concept simulation of a collapsing cloud, which produces high-mass stars and is subsequently partially ionised by them. The presented code is a valuable tool for future star formation studies, and it can be used for modelling a broad range of additional astronomical problems involving ionising radiation and hydrodynamics.en_US
dc.description.sponsorship"This thesis received funding from the European Research Council for the FP7 ERC advanced grant project ECOGAL. The presented work used the DiRAC Complexity system, operated by the University of Leicester IT Services, which forms part of the STFC DiRAC HPC Facility ( This equipment is funded by BIS National E-Infrastructure capital grant ST/K000373/1 and STFC DiRAC Operations grant ST/K0003259/1. DiRAC is part of the National E-Infrastructure." -- Acknowledgementsen
dc.publisherUniversity of St Andrews
dc.relationPetkova, M.A., Laibe, G., Bonnell, I.A.. Fast and accurate Voronoi density gridding from Lagrangian hydrodynamics data. J Comp Phys 2018;353:300–315. doi:10.1016/ arXiv:astro-ph/1710.07108en_US
dc.relationCloudy with a chance of starlight : coupling of smoothed particle hydrodynamics and Monte Carlo radiative transfer for the study of ionising stellar feedback (thesis data) Petkova, M.A., University of St Andrews, 25 November 2018, DOI:
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 International*
dc.subjectVoronoi griden_US
dc.subjectRadiation hydrodynamicsen_US
dc.subjectMonte Carlo radiative transferen_US
dc.subjectSmoothed particle hydrodynamicsen_US
dc.subject.lcshRadiative transferen
dc.subject.lcshIonizing radiationen
dc.subject.lcshStars--Formation--Mathematical modelsen
dc.titleCloudy with a chance of starlight : coupling of smoothed particle hydrodynamics and Monte Carlo radiative transfer for the study of ionising stellar feedbacken_US
dc.contributor.sponsorSeventh Framework Programme (European Commission)en_US
dc.type.qualificationnamePhD Doctor of Philosophyen_US
dc.publisher.institutionThe University of St Andrewsen_US

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