Canadian Contributions Studies for the WFIRST Instruments
ABSTRACT
WFIRST-AFTA is the NASA’s highest ranked astrophysics mission for the next decade that was identified in the New World, New Horizon survey. The mission scientific drivers correspond to some of the deep questions identified in the Canadian LRP2010, and are also of great interest for the Canadian scientists. Given that there is also a great interest in having an international collaboration in this mission, the Canadian Space Agency awarded two contracts to study a Canadian participation in the mission, one related to each instrument. This paper presents a summary of the technical contributions that were considered for a Canadian contribution to the coronagraph and wide field instruments.
1. INTRODUCTION
The Wide-Field Infrared Survey Telescope – Astrophysical Focus Telescope Asset (WFIRST-AFTA) mission is the NASA’s highest ranked mission that was identified in the 2010 National Academy of Science decadal survey: New World, New Horizon. Its 2.4-m telescope aperture combined with its exquisite image quality and it field-of-view 90 times larger than Hubbles’s ACS and 200 times larger than WFC3/IR will give scientists access to a set of high-quality data to attempt to answer top modern scientific questions. The mission has entered its formulation phase at the beginning of 2016 with an expected launch date in 2025.
The mission science objectives will be achieved using two main instruments, the Wide Field Instrument (WFI) and the Coronagraphic Instrument (CGI). The WFI has an image plane composed of 18 H4RG detectors that covers a FoV of 0.281 deg2 . An 8-position element wheel will include six filters ranging from 0.76 μm to 2.0 μm, a dark channel and a grism channel to do slitless spectroscopy between 1.35 μm and 1.89 μm. The WFI will also include a separate Integral Field Channel (IFC) based on an image slicer that is baselined to provide spectra over the 0.6 μm to 2.0 μm waveband over two FoVs. One FoV will be optimized for the supernovae survey while the second FoV will be optimized for galaxy characterizations. The CGI will aim at detecting faint companions at unprecedented contrast levels to enable the detection of old evolved planet in reflected light and enabling an overlap of indirect detection techniques and direct imaging for the first time.
The tremendous amount of data that will be collected by WFIRST and its quality makes the mission very appealing to Canadian scientists. The top recommendation of the Canadian decadal survey, the LRP2010, was for an involvement in a survey mission that can shed new light on the mystery of dark energy, which was reaffirmed in its 2015 mid-term review. WFIRST was identified as a mission that would fulfill this goal. A Canadian involvement in the WFIRST mission would not only allow our scientists to have access to the data but also to beneficiate from the socio-economic advantages that come with an involvement in a world-class observatory that will find clues to answer the top scientific questions of our time in astrophysics.
In this context, the Canadian Space Agency has awarded two contracts in 2014 to evaluate possible Canadian contributions to the mission: one on contributions to the WFI and one on the coronagraph instrument (CGI). The main goal of these studies is to provide recommendations on the technologies that Canada could provide based on their alignment with Canada’s space policy framework and their technological maturity. This paper presents brief summaries on the work and recommendations that issued from these studies.
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