Extreme Contrast Ratio Imaging of Sirius with a Charge Injection Device

TL;DR

This paper demonstrates the potential of a 32-bit charge injection device (CID) for extreme contrast ratio astronomical imaging, achieving a contrast of 1 part in 20 million in Sirius observations, and discusses combining it with PSF suppression techniques for enhanced imaging.

Contribution

The paper introduces a new application of a 32-bit CID for high-contrast astronomical imaging and explores its capabilities and potential when combined with PSF suppression methods.

Findings

Achieved a contrast ratio of 1 part in 20 million at 2 arc minutes from Sirius.

Demonstrated the CID's ability to perform ECR imaging under suboptimal atmospheric conditions.

Suggested combining CID with simple PSF suppression techniques for improved results.

Abstract

The next fundamental steps forward in understanding our place in the universe could be a result of advances in extreme contrast ratio (ECR) imaging and point spread function (PSF) suppression. For example, blinded by quasar light we have yet to fully understand the processes of galaxy formation and evolution, and there is an ongoing race to obtain a direct image of an exoearth lost in the glare of its host star. To fully explore the features of these systems we must perform observations in which contrast ratios of at least one billion can be regularly achieved with sub 0.1" inner working angles. Here we present the details of a latest generation 32-bit charge injection device (CID) that could conceivably achieve contrast ratios on the order of one billion. We also demonstrate some of its ECR imaging abilities for astronomical imaging. At a separation of two arc minutes, we report a direct contrast ratio of Delta(m_v)=18.3, log(CR)=7.3, or 1 part in 20 million, from observations of the Sirius field. The atmospheric conditions present during the collection of this data prevented less modest results, and we expect to be able to achieve higher contrast ratios, with improved inner working angles, simply by operating a CID at a world-class observing site. However, CIDs do not directly provide any PSF suppression. Therefore, combining CID imaging with a simple PSF suppression technique like angular differential imaging, could provide a cheap and easy alternative to the complex ECR techniques currently being employed.