Master's Thesis Defense by Jasmine Lynne MacKenzie – Niels Bohr Institute - University of Copenhagen

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Master's Thesis Defense by Jasmine Lynne MacKenzie

Analysis of the Gravitational Microlensing Event OGLE-2014-BLG-0124L Using Ground-Based Parallax

The study of exoplanets is the first step to finding life elsewhere in the galaxy. While the Doppler method and the Transit method, the two most common ways of detecting exoplanets, have confirmed exoplanetary detections numbering in the thousands, they each have a bias toward larger planets orbiting closer in towards their host star. Gravitational microlensing is one of the few methods sensitive to systems like our own. This includes Earth-like planets orbiting at Earth-like distances from their star, and planets orbiting beyond the snow line. This allows us to probe a parameter space around a wide range of host stars throughout the galaxy towards the galactic bulge which is difficult or impossible to explore with other methods. Gravitational microlensing occurs when a body of stellar mass or smaller passes in front of a light source, e.g. another star. The light is then deflected and magnified by the foreground lens as described by General Relativity. If the star happens to have a planet orbiting around it, the planet can contribute to the magnification as well, creating what is called a binary microlensing event.

In my thesis, I investigated the viability of using solely ground-based data to model planetary microlensing events. I concluded that for the event OGLE-2014-BLG-0124L, the use of simultaneous observations by several observatories on Earth gave a similar amount of information as what could be obtained by including satellite data. Because satellite data are much more expensive and not accessible for all microlensing events, this result proves promising for the future of large scale surveys from the ground, and our understanding of how unique our own planetary system is in the galaxy.

Supervisor: Uffe Gråe Jørgensen, Niels Bohr Institute, University of Copenhagen

Co-supervisor: Dr. Markus Hundertmark, Center for Astronomy, University of Heidelberg