Research and Support Participation Opportunities
Abstracts of Selected Proposals
This document provides the abstracts of proposals selected for funding within the Roman program. Principal Investigator (PI) name and institution, lead Co-I name and institution, proposal title, and category are also included. 91 proposals were received in response to this opportunity. On July 5, 2023, 30 proposals were selected for funding.
Coronagraph Community Participation Program
Coronagraph Instrument testing and performance evaluation in single- and binary star modes
Calibrating Roman’s Coronagraphic Imaging and Polarimetry Modes
Data driven investigations of the Coronagraph Instrument as a starlight suppression yardstick
Roman’s Giants: Jovian Exoplanet Modeling and RCI Detectability
Target Selection and Observation Modeling Tools for Coronagraph Tech Demo and Beyond
Imaging and Characterizing Exoplanets with the Roman Coronagraph and Open-Source Tools
Circumstellar Dust with the Roman Coronagraph
Coronagraph Instrument testing and performance evaluation in single- and binary star modes
Ruslan Belikov / NASA – Ames Research Center, PI
Eduardo Bendek / Jet Propulsion Laboratory, Institutional PI
Dan Sirbu / NASA – Ames Research Center, Co-I
We propose to assist the Roman Coronagraph Instrument team with laboratory testing, as well as performance predictions, in both single as well as multi-star modes. The main objectives of this proposal are to: (1) gain even greater confidence in reaching the Threshold Technology Requirement (TTR); (2) advance performance capability and identify opportunities beyond TTR, especially ones that are enabled by the multi-star contributed mode. In order to achieve these objectives, our work will consist of three inter-related parts: pure single-star mode; MSWC-assisted single star mode; and multi-star mode. We describe these in what follows.
(1) We will work with the Roman Coronagraph Instrument team to test and advance the performance of the pure single star mode (on the OMC test bench, or the new planned bench for the flight instrument). In particular, we will assist with testing and optimizing baseline single-star algorithms, finding limiting factors, and gaining a better overall understanding of technical subtleties of operating the Coronagraph Instrument. In addition, we will contribute computation efficiency improvements based on algorithms we’ve developed, such as semi-analytical approximations (e.g. small-star approximation), zoomFFT, etc. The exact details of this work are meant to be flexible and adapt to the needs of the Roman Coronagraph Instrument test program. We will leverage our experience working with the OMC test bench over the past 2 years, both in HLC single-star mode, as well as SPC single- and multi-star modes.
(2) We will take advantage of synergies with our MSWC project to maximally benefit standard Coronagraph Instrument single-star modes. In particular, the Coronagraph Instrument models we developed for binary star sources are also useful for analyzing background sources contaminating single-star targets. This is valuable because the Coronagraph Instrument observation time is limited, so we cannot afford to spend time on targets that turn out to be contaminated by off-axis sources. The same models are also useful to more accurately assess the viability of binary stars as single-star mode targets. In addition, we will study several techniques that enhance single-star mode operation by using information or metrology provided by the MSWC mask. The basic idea is to test certain aspects of MSWC which happen to be applicable to single-star modes. This reduces the risk of TTR, supports several Coronagraph Instrument Technology Objectives, and helps enable performance beyond TTR.
(3) Finally, we will further develop and test the multi-star mode for flight observations, leveraging and complementing the work we are doing as part of the ISFM program, and in particular bring MSWC is as close to flight-ready as possible, not only in terms of performance, but also in terms of compatibility with flight software. We will coordinate with the Roman Coronagraph Instrument flight software team to develop MSWC code to flight-readiness. Also, in case the Coronagraph Instrument allows ground testing of instrument modes other than HLC, we plan to be ready to perform a test with flight hardware. We will also incorporate our findings and characterizations of flight components into MSWC mode performance estimates.
The primary significance of this work lies in gaining further confidence in achieving the Coronagraph Instrument TTR and Technology Objectives, which is of critical importance to ensure the Coronagraph Instrument success as a technology demo. In addition, the performance enhancements we described above have the potential to make the Coronagraph Instrument a powerhouse of exoplanet science in its own right.
Calibrating Roman’s Coronagraphic Imaging and Polarimetry Modes
Max Millar-Blanchaer / University of California – Santa Barbara, PI
The Roman Space Telescope Coronagraphic imaging modes promise to demonstrate exciting new technologies that will set the stage for NASA’s next great observatory, the Habitable Worlds Observatory. Achieving both the baseline requirements and meeting the “best-effort” goals will require careful target selection and a sophisticated calibration program. Here we propose a Roman Coronagraph Community Participation Program contribution that will cover four main aspects of the call for proposals: B, E, F, H and I. Our team will focus on the development of detailed calibration simulations, calibration analysis toolkits, and the development of software for applying calibrations to in-flight calibration data. These tasks will be critical for the successful achievement of the primary TTRL5 mission success requirement. A second major component of our proposed program will be to focus on Roman’s polarimetry mode. The Roman polarimetry mode will provide a unique opportunity to demonstrate high contrast polarimetry at contrasts that are not achievable from the ground, opening the doors to future polarimetric studies of not only disks, but planets as well. We will develop a polarimetric commissioning and calibration plan, complete with image processing analysis software. Calibration target vetting and precursor observations for the polarimetry mode will be included where necessary. Our team brings a breadth of experience in the commissioning, characterization, calibration and use of both ground-based and space-based high contrast imaging instruments. Furthermore, the PI is an expert in the calibration and use of high-contrast polarimetric instrumentation. Given the breadth of expertise and experience of our team, should the project need our efforts to focus on other topical areas or should resources prevent a focus on the polarimetry mode, there are many other topical areas the team is interested in.
Data driven investigations of the Coronagraph Instrument as a starlight suppression yardstick.
Laurent Pueyo / Space Telescope Science Institute, PII
Objectives:
We will work with the Roman Coronagraph Instrument project to maximize the return of the Coronagraph Instrument technology demonstration mission, and transfer knowledge to the Astro2020 recommended Habitable World Observatory (HWO). We will do so by carefully analyzing ground test data during the initial period of performance.
Background:
The Coronagraph Instrument is the only flight demonstrator of a suite of technologies that are critical to exo-earth detection and characterization with HWO. For instance, lessons learned from the Coronagraph Instrument ground testing will inform the experimental design of system level technology demonstrations that will occur under the purview of the Great Observatories Maturation Program (GOMAP). Successful Coronagraph Instrument operations during the technology demonstration phase will define the baseline exoplanet imaging observing sequence for HWO during formulation (Phase A). Because the Coronagraph Instrument is a class D instrument, with reduced assurance standards permitted, the Coronagraph Instrument I\&T data might not be as thoroughly scrutinized as was done for previous NASA flagships such as JWST. Our proposed CPP program will augment existing Coronagraph Instrument project resources to characterize performance and optimize the observations during the technology demonstration phase. We will also extrapolate the Coronagraph Instrument results to HWO.
Methods:
We propose to conduct a suite of data driven investigations based on the Coronagraph Instrument ground test measurements to inform HWO technology maturation and mission formulation plans, and maximize the return of the Coronagraph Instrument the technology demonstration. This will include:
- Evaluating raw contrast model uncertainties using ground tests data, and establishing best practices to set Model Uncertainty Factors (MUFs) for HWO error budgets.
- Quantifying the relationship between model uncertainties and WFS\&C convergence time and identifying the tall poles in the instrument’s configuration. These will be precious lessons learned to design GOMAP demonstrators and preliminary HWO architectures during mission formulation.
- Measuring the wavefront noise rejection function of the Coronagraph Instrument’s WFS\&C subsystems –either using the LOWFS or the science camera. We will then use these measurements as yardsticks to quantify how much ground GOMAP needs to cover in order to demonstrate HWO compatible wavefront stability.
- Developing a target list composed of a wide range of companions, from stellar binaries to self-luminous planets. We will build an empirical flight contrast ladder that will be essential to demonstrate the Coronagraph Instrument’s science capabilities during its commissioning and technology demonstration phases.
- Designing observing sequences for the Coronagraph Instrument’s technology demonstration phase that are as informative as possible for HWO.
Significance:
This work will help optimize the Coronagraph Instrument observations during the technology demonstration phase, which will in turn pave the way towards compelling Coronagraph Instrument observations later in the mission. Such successful observations will provide a unique opportunity to anchor HWO yield predictions with the Coronagraph Instrument data.
Roman’s Giants: Jovian Exoplanet Modeling and RCI Detectability
Tyler Robinson / University of Arizona, PI
The Roman Coronagraph Instrument (RCI) aboard NASA’s Nancy Grace Roman Space Telescope is a critical technology demonstration to guide many future NASA endeavors in high-contrast imaging. The stated RCI Threshold Technical Requirement (TTR) represents a challenge that can only be met through collaborative efforts spanning engineers, instrument scientists, and exoplanet modeling experts. To enable target selection and prioritization, and to empower future interpretation of RCI results, we propose to execute a novel grid of giant exoplanet atmospheric models, spectral simulations, and inverse studies. The atmospheric models and associated spectral simulations will be guided by likely RCI targets and anticipated planetary properties. Our inverse studies will use the planned spectral models to demonstrate the range of exoplanet atmospheric science that can be completed with varying levels of RCI observing time commitment.
We anticipate active engagement with a broader CPP Team to enable improved star/exoplanet/disk/instrument scene models and to best understand the connections between planned instrument performance, the likelihood of TTR success, and the potential for first-of-its-kind exoplanet atmospheric science that would prove foundational for the forthcoming Habitable Worlds Observatory. Our proposed efforts are relevant to the CPP topical area of “[m]odeling astrophysical targets” and, as stated in the call, the efforts are, then, relevant to NASA’s Science Plan. More specifically, our RCI-focused modeling studies enable understanding of the universe and a search for life elsewhere (2022 Strategic Plan, Objective 1.2) and are specifically designed to enable new space technologies (2022 Strategic Plan, Objective 3.1) within NASA’s Decadal Survey-guided “balanced science program” (2020-2024 NASA Science Plan, Strategy 1.1).
Target Selection and Observation Modeling Tools for the Roman Coronagraph Technology Demonstration and Beyond
Dmitry Savransky / Cornell University, PI
The Space Imaging and Optical System Laboratory (SIOSlab) at Cornell University has been actively supporting the Nancy Grace Roman Space Telescope Coronagraph Instrument since pre-Phase A activities. We currently maintain two open-source, community resources: a one-to-one port of the internal JPL Exposure Time Calculator (ETC) for the Roman coronagraph (available as a module of the publicly distributed EXOSIMS software framework) and a publicly accessible database of known planetary companions that could potentially be imaged by the Roman coronagraph (the Imaging Mission Database). We propose a suite of activities under the Coronagraph Community Participation Program aimed to further develop and expand both of these resources, and specifically targeting topic areas A (modeling of astrophysical targets), B (selecting suitable observing targets), D (planning observations) and M (enabling activities for possible further use of the coronagraph).
Specifically, we will continue development and maintenance of the EXOSIMS Roman coronagraph ETC to account for improvements in the instrument model and new characterizations of the flight instrument. For each ETC update, we will recompute detection probabilities for all targets in the Imaging Mission Database. The database will also continuously be updated with new targets as they are discovered, and with new orbital fits for current targets as they appear in the literature. We will augment the existing photometric model grids used in the database to provide better predictions of known planet detection probabilities with the coronagraph, and will add optimal observation times for all targets observable by the coronagraph. Optimal observing times will be computed by applying new methodologies, recently published by our group, for the use of radial velocity data to optimize imaging observations. We will also expand these methodologies to work with all relevant targets in the database. Finally, we will continue development of the EXOSIMS blind search simulation capabilities for the Roman coronagraph to prepare for any potential science program following a successful technology demonstration, and similarly update the blind search (and unknown companion) search targets in the database.
In addition to these specific activities, the PI and members of the proposing team have broad expertise and experience in coronagraphic exoplanet imaging and instrumentation, and could support multiple other activities, as required by the final makeup of the CPP team.
Imaging and Characterizing Exoplanets with the Roman Coronagraph and Open-Source Tools
Jason Wang / Northwestern University – Evanston, PI
I propose to join the Roman Coronagraph team to assist in the target selection, data simulation, data reduction, instrument performance characterization, and science demonstration, with a focus on adapting current open-source tools to support the Roman Coronagraph. I am a lead developer of two open-source tools popular in the community: “pyKLIP” for stellar point spread function subtraction and exoplanet characterization and “orbitize!” for Bayesian orbit fitting of imaged exoplanets. I propose to add functionality to these packages so that they can be used to assist in the technology demonstration activities. This will ensure open and reproducible science and will mature the tools to analyze visible-light coronagraphic data from space.
In the area of target selection, “orbitize!” can be used and upgraded to predict the locations of known imaged planets and planets detected through indirect methods such as Gaia astrometry. This will allow us to know which objects will be in the Coronagraph field of view and which need ground-based follow-up to refine their orbits. In the area of data simulation and reduction, I will work on optimizing “pyKLIP” for Roman Coronagraph data. pyKLIP is widely used for coronagraphic data from ground-based telescopes and JWST and was the top performing algorithm in the Roman Exoplanet Imaging Data Challenge, detecting faint planets that other algorithms did not. Using simulated data, I will further improve pyKLIP such as by using orbital constraints as priors in the detection framework and by adapting it for the spectroscopic mode of the Coronagraph. In the area of instrument performance characterization, I have a decade of experience calibrating and characterizing high-contrast instruments such as the Gemini Planet Imager and the Keck Planet Imager and Characterizer, and will bring my expertise to the Roman Coronagraph. I will create tutorials and pipelines based on pyKLIP to easily assess the final planet sensitivity of the Roman Coronagraph in simulation, in the lab, and in space. I can also help develop astrometric and spectrophotometric calibration strategies for the instrument. In the area of science demonstration, I will create recipes and pipelines to measure the photometry, astrometry, orbits, and spectral properties of exoplanets with simulated and real data from the Coronagraph. For reflected light planets, orbital and photometric information are covariant, and I will add functionality to “orbitize!” to include constraining the phase function of reflected light planets in orbital fits. In all these cases, in addition to contributing to the Coronagraph Instrument’s technology demonstration, the software modifications would be accessible to the entire astronomical community in well-established software packages, and the same functionality can be used in future space missions such as the Habitable Worlds Observatory.
Circumstellar dust: A nexus of performance, calibration, and science potential in the Roman coronagraph technology demonstration
Schuyler Wolff / University of Arizona, PI
Planetary system architectures include rocky planets, gas giant planets, and dusty debris. All three components will appear in high contrast images from NASA’s future Habitable Worlds Observatory (HWO). Along with its key flight demonstration of coronagraphy with precision wavefront control, the Roman Coronagraph (RC) will advance our understanding of how well HWO will be able to study these three elements of exoplanetary systems. The instrument should not only produce the first direct detection of a giant planet in reflected starlight, but can also provide unprecedented views of the spatial structure and scattering properties of circumstellar dust. The strong potential of RC polarimetry allows disk modeling degeneracies to be broken, allowing for the extraction of information on the size, composition and porosity of the scattering particles. We suggest that the Roman Coronagraph Team work to fully define the instrument’s science potential for exozodi and debris disk studies.
Our proposed involvement in the RC Team focuses on two areas. The first focus area is to use the needs of exozodi and debris disk imaging to motivate investigations of instrument performance and calibration for extended sources. 1.) By fully exercising the built-in polarimetry mode of RC in Band 1 and Band 4, we will learn how well its instrumental polarization can be modeled, the limits to polarization sensitivity including the efficacy of polarimetric differential imaging at very high contrast levels, and the accuracy of its polarimetric calibration. From such work the RC team can gain confidence that polarized light can be a science tool for RC and eventually HWO, and not an optical design issue that curtails high contrast performance. 2.) By investigating the limits to LOWFS operation, our intended studies will map out the parameter space of dark hole contrast versus target star brightness - defining the full extent of what RC and eventually HWO can achieve in the way of disk and exozodi detections in the solar neighborhood. 3.) Building from the PI’s ongoing involvement in JWST coronagraphy, we will provide a customized pipeline module for analyzing tech demo data of extended disk sources.
Informed by the results of the above, our second focus area is to develop options for two potential community projects that would figure into a decision on RC utilization beyond the tech demo phase. 4.) By leading the RC team and broader community in the definition and preparation of a ready-to-execute exozodi survey program, we will enable a timely NASA HQ decision on whether the benefits of an exozodi survey would justify the required resources, reducing the risk to the primary Roman Science mission and (should the survey go ahead) to HWO mission lifetime requirements. 5.) By building a database of disk models for the known debris disks accessible to RC, we can gain confidence that tech demo observations of extended sources will achieve their goals while simultaneously laying the groundwork for a possible future survey of inner warm debris disks with RC.
The success of future facilities like the Roman Coronagraph will require scientists with both a working knowledge of the technical challenges of high contrast imaging and an understanding of the fundamental research questions. We believe that our expertise in instrument commissioning and calibration, in disk science and disk modeling, and in data pipeline development will serve the community and the Roman Coronagraph Team.
