The hunt for Sirius Ab: Comparison of algorithmic sky and PSF estimation performance in deep coronagraphic thermal-IR high contrast imaging

Joseph D. Long; Jared R. Males; Katie M. Morzinski; Laird M. Close; Frans Snik; Matthew A. Kenworthy; Gilles P. P. L. Otten; John Monnier; Volker Tolls; Alycia Weinberger

arXiv · 1807.04361

The hunt for Sirius Ab: Comparison of algorithmic sky and PSF estimation performance in deep coronagraphic thermal-IR high contrast imaging

Joseph D. Long·Jared R. Males·Katie M. Morzinski·Laird M. Close·Frans Snik·Matthew A. Kenworthy·Gilles P. P. L. Otten·John Monnier·Volker Tolls·Alycia Weinberger

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Abstract

Despite promising astrometric signals, to date there has been no success in direct imaging of a hypothesized third member of the Sirius system. Using the Clio instrument and MagAO adaptive optics system on the Magellan Clay 6.5 m telescope, we have obtained extensive imagery of Sirius through a vector apodizing phase plate (vAPP) coronagraph in a narrowband filter at 3.9 microns. The vAPP coronagraph and MagAO allow us to be sensitive to planets much less massive than the limits set by previous non-detections. However, analysis of these data presents challenges due to the target's brightness and unique characteristics of the instrument. We present a comparison of dimensionality reduction techniques to construct background illumination maps for the whole detector using the areas of the detector that are not dominated by starlight. Additionally, we describe a procedure for sub-pixel alignment of vAPP data using a physical-optics-based model of the coronagraphic PSF.

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Joseph D. Long, Jared R. Males, Katie M. Morzinski, Laird M. Close, Frans Snik, Matthew A. Kenworthy, Gilles P. P. L. Otten, John Monnier, Volker Tolls, Alycia Weinberger. 2018-07-11. The hunt for Sirius Ab: Comparison of algorithmic sky and PSF estimation performance in deep coronagraphic thermal-IR high contrast imaging. https://arxiv.org/abs/1807.04361

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