The Nancy Grace Roman Space Telescope Coronagraph Instrument (CGI) technology demonstration

Kasdin, N. Jeremy; Bailey, Vanessa P.; Mennesson, Bertrand; Zellem, Robert T.; Ygouf, Marie; Rhodes, Jason; Luchik, T. S.; Zhao, Feng; Riggs, A. J. Eldorado; Seo, Byoung-Joon; Krist, John; Kern, Brian; Tang, Hong; Nemati, Bijan; Groff, Tyler D.; Zimmerman, Neil; Macintosh, Bruce; Turnbull, Margaret; Debes, John H.; Douglas, Ewan S.; Lupu, Roxana

doi:10.1117/12.2562997

Cited by 37 publications

(22 citation statements)

References 27 publications

(18 reference statements)

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“…The Roman Space Telescope has certain characteristics that make it particularly challenging for high-contrast imaging. 11,35 Specifically, the central obscuration is relatively large (∼30% of pupil diameter), and the six struts are several times wider (with widths of 3.2% of pupil diameter) than for any proposed mission concepts for high-contrast imaging. Discontinuities in the pupil and especially central obscurations heavily affect the performance of the system.…”

Section: Our Case Study: the Roman Coronagraph Hlcmentioning

confidence: 99%

“…12,33,34 The work presented here was done in the context of optimizing the design process for the Nancy Grace Roman Space Telescope (Roman) Coronagraph Instrument's HLC. The Roman coronagraph 35 is an advanced technology demonstrator that will pave the way for future direct imaging missions by demonstrating key coronagraph technologies in space. The HLC in the Roman coronagraph is designed by carefully solving for the DMs shapes and the dielectric layer shape simultaneously in a small-step linearized approach.…”

Section: Introductionmentioning

confidence: 99%

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Coronagraph design with the electric field conjugation algorithm

Llop-Sayson

Riggs

Mawet

et al. 2022

J. Astron. Telesc. Instrum. Syst.

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The requirements for a coronagraph instrument to image and obtain spectra of rocky planets around bright stars from space are tight. Indeed, the goal of imaging an Earth-like planet requires a starlight suppression system that cancels light to a level of 10 −10 with sufficient stability and robustness to errors. Furthermore, the key science questions necessitate an adequate sample size; consequently, the throughput of the coronagraph drives the achievable yield of a given mission. The trade among achievable raw contrast, sensitivity to wavefront errors, and throughput poses a challenging problem in coronagraph design. The complexity of this problem drives us toward the simultaneous solving of all optical elements. We present a set of methods to optimize the design of a coronagraph. We implement these for the case of the hybrid Lyot coronagraph in the context of the Nancy Grace Roman Space Telescope Coronagraph Instrument. We discuss our findings in terms of coronagraph instrument design, and optical subsystems, and performance interplay.

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Section: Our Case Study: the Roman Coronagraph Hlcmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Coronagraph design with the electric field conjugation algorithm

Llop-Sayson

Riggs

Mawet

et al. 2022

J. Astron. Telesc. Instrum. Syst.

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“…Another satellite with a detection range in the visible and near-infrared regions is the Nancy Grace Roman space telescope. This platform will be able to collect data over a much greater volume than any current instrument, be able to detect new Jupiter sized planets and so should also add to our knowledge of MACHOS and hence DM [28]. The planned launch date is sometime in 2025, so it may be collecting data before the James Webb telescope.…”

Section: Introductionmentioning

confidence: 99%

Dark Matter in Spiral Galaxies as the Gravitational Redshift of Gravitons

Oliveira¹,

Smith²

2022

Dark Matter - Recent Observations and Theoretical Advances

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Several recent attempts to observe dark matter with characteristics similar to atomic or subatomic particles as Weakly Interacting Massive Particles (WIMPs) have failed to detect anything real over a wide energy range. Likewise, considerations of large, non-emitting objects as the source of most dark matter fall short of expectations. Here we consider the possibility that massless gravitons suffering slow redshift may be responsible for the properties of spiral galaxies attributed to dark matter. Particles such as gravitons will be extremely difficult to directly detect; the best we can envision is measuring this influence on stellar and galactic motions. Since the motions of stars and galaxies are non-relativistic, we can apply our idea to describe the expected large-scale motions using only Newtonian mechanics. Using our assumption about the importance of the graviton, we here describe the well-known Tully-Fisher relationship of spiral galaxies without resorting to hypothesizing exotic WIMPs or invoking modifications of Newtonian dynamics (MoND).

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“…Searches like the Gemini Planet Imager and Nancy Grace Roman Space Telescope (Roman) Coronagraphic Instrument (CGI) 7 are sensitive to larger planets with larger planet-star separations and longer orbital periods. 1 They make use of Brown completeness to plan blind searches.…”

Section: Introductionmentioning

confidence: 99%

“…This paper presents a method, implemented in the EXOSIMS modeling software, 3 for calculating integration time adjusted completeness that allows us to investigate exactly how much the original completeness definition overestimates planet yields. EXOSIMS is an exoplanet direct imaging mission modeling software used to simulate the Roman CGI 7 and future mission concepts such as HabEx 8 and LUVOIR. 9 EXOSIMS simulates populations of planets, observatories, instruments, and underlying dynamics to create full, end-to-end mission simulations.…”

Section: Introductionmentioning

confidence: 99%

Integration time adjusted completeness

Keithly

Savransky

Spohn

2021

J. Astron. Telesc. Instrum. Syst.

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Future, large-scale, exoplanet direct-imaging missions will be capable of discovering and characterizing Earth-like exoplanets. These mission designs can be evaluated using completeness, the fraction of planets from some population that are detectable by a telescope at an arbitrary observation time. However, the original formulation of completeness uses instrument visibility limits and ignores additional integration time and planetary motion constraints. Some of the sampled planets used to calculate completeness may transit in and out of an instrument's geometric and photometric visibility limits while they are being observed, thereby causing the integration time agnostic calculation to overestimate completeness. We present a method for calculating completeness that accounts for the fraction of planets that leave the visibility limits of the telescope during the integration time period. We define completeness using the aggregate fraction of an orbital period during which planets are detectable, calculated using the specific times that planets enter and leave an instrument's visibility limits and the integration time. To perform this calculation, we derive analytical methods for finding the planet-star projected separation extrema, times past periastron that these extrema occur, and times past periastron that the planet-star projected separation intersects a specific separation circle. We also provide efficient numerical methods for calculating the planet-star difference in magnitude extrema and times past periastron corresponding to specific values Δmag. Our integration time adjusted completeness shows that, for a planned star observation at 25 pc with 1-day and 5-day integration times, integration time adjusted completeness of Earth-like planets is reduced by 1% and 5% from the integration time agnostic completeness, respectively. Integration time adjusted completeness calculated in this manner also provides a computationally inexpensive method for finding dynamic completeness-the completeness change on subsequent observations. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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The Nancy Grace Roman Space Telescope Coronagraph Instrument (CGI) technology demonstration

Cited by 37 publications

References 27 publications

Coronagraph design with the electric field conjugation algorithm

Coronagraph design with the electric field conjugation algorithm

Dark Matter in Spiral Galaxies as the Gravitational Redshift of Gravitons

Integration time adjusted completeness

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