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Multiband Polarimetric Imaging of Debris Disks with the Gemini Planet Imager
- Arriaga, Pauline L
- Advisor(s): Fitzgerald, Michael P
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.
Main Content
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