Matthijs van der Wild

Projects

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Automated image processing with LOFAR data

+ My current activities include the implementation and improvement of an automated data reduction pipeline for radio data, enabling high-resolution very-long baseline interferometry (VLBI). + The International LOw-Frequency ARray (LOFAR) Telescope is an interferometer which has radio stations placed across Europe. + It provides a wealth of data which enables the detection and imaging of radio sources with high sensitivity and great detail. + The calibration of the individual radio stations, however, is technically challenging. + As a result, the full LOFAR telescope is still underutilised. + My pipeline addresses this with the development of tools that do not rely on human input, and which produce reliable and reproducible results on platforms that are accessible to astronomers. + It extends the resolving power of LOFAR from the Dutch stations to the full international array, delivering sub-arcsecond resolution imaging in a way that is scalable, portable and reproducible. +

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Inflation and quantum geometrodynamics in scalar-tensor theories

+ I have investigated the behaviour of a general class of scalar-tensor theories of gravity when effects from quantum gravity are relevant. + One such extension adds a scalar degree of freedom to the gravitational interaction, which is then called a scalar-tensor theory. + Scalar-tensor theories are an extension to the theory of general relativity which add a scalar degree of freedom to the metric tensor to describe the gravitational interaction. + Such extensions can be motivated from cosmology, where the energy of the additional field can drive cosmic inflation, and particle physics, where the Standard Model supplies a natural candidate scalar degree of freedom through the Higgs field. + I have developed a method to systematically expand the full quantum dynamics of these models around solutions to the classical equations of motion, and how these classical solutions provide a background on which the quantum gravitational perturbations propagate. +

+ I have applied this strategy to inflationary cosmology. + In this setup, the gravitational scalar field fulfills the role of the inflaton. + I have determined observational signatures from both slow-roll inflation and quantum gravitational corrections in the primordial power spectrum, and have made predictions on the parameters of the models in the event that sufficiently precise data is available. + This would allow an entire class of cosmological models to be ruled out if the structure of these signatures is absent from the data. +

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+ More information about this can be found in my thesis. +