Multiband Polarimetric Imaging of Debris Disks with the Gemini Planet Imager.

다국어 초록 (Multilingual Abstract)

High-contrast imaging techniques have enhanced our capabilities in studying the formation and evolution of exo-solar disks and planets. In my research, I have studied the instrumentation, data reduction, and data analysis involved in this area. Many high-contrast imagers operate in the near-infrared wavelengths, the systems of which are rapidly developing with new technology. To this end, I have characterized the infrared detector of the upgraded Keck OSIRIS imager as well as explored methods for blocking out infrared radiation from the telescope components which pollute the desired scientific signal. Moving downstream from the data collection, I improved data reduction methods for suppressing the stellar signal from high-contrast images of disks and planets, as well as writing publically available code to forward model biases introduced from these subtraction methods. I generalized the code for these methods such that they can be used for most high-contrast imaging instruments, and optimized it for disks such that it ran two order of magnitudes faster than code optimized for planet detection. I studied the efficacy of my forward modeling module in further efforts to make the code more generally used by the scientific community. I used these techniques to study the debris disk HR4796A using multi-wavelength integral field polarimetric data form the Gemini Planet Imager (GPI). HR4796A hosts a well-studied debris disk with a long history due to its high fractional luminosity and favorable inclination lending itself well to both unresolved and resolved observations. We modelled a purely geometric disk in order to extract geometry parameters, polarized fraction and total intensity scattering phase functions for these data. We find that conventional methods that are used to model debris disks cannot produce a satisfactory model of the phase functions of the disk, indicating the need for more sophisticated grain models.