The Roman Galactic Exoplanet Survey Project Infrastructure Team

PI: B. Scott Gaudi / Ohio State University

The primary science driver for the Galactic Bulge Time Domain Survey (GBTBS) of the Nancy Grace Roman Space Telescope (Roman) is the requirement to obtain a statistical census of cold planets orbiting stars in the Galactic disk and bulge using the gravitational microlensing method. We refer to this as the Roman Galactic Exoplanet Survey (RGES). This science is at least as compelling as when Roman was selected by the 2010 Decadal Survey. The 2020 Decadal Survey states that Roman is “the only platform in the coming decades that can produce a statistical census of planetary occurrence as a function of orbital separation and mass, from terrestrials to gas giants, beyond 1 AU”.

We propose to develop the infrastructure required to plan, execute, and extract cold exoplanet demographics from the RGES survey. Specifically, we will (1) confirm and/or reconfirm the five level-1 RGES science requirements, (2) improve the microlensing event rate and yield calculations by improving the input Galactic models, incorporating new measurements of the near-infrared event rate obtained by the PRime-focus Infrared Microlensing Experimen (PRIME) survey, (3) develop and test the prototype photometry and astrometry pipeline, event detection pipeline, light curve modeling pipeline, and detection efficiency (or completeness) pipeline, which we will make publicly-available and user-friendly, (4) develop the occurrence rate formalism and methodology. In order to test and refine the photometry and astrometry pipeline, we will develop detailed image simulations that reproduce, as faithfully as possible, the actual images obtained by the Roman Wide Field Instrument.

The number of US scientists working in the exoplanet microlensing field is usually small, and the microlensing method is considered to be obscure by many scientists in the exoplanet field. In order to overcome this shortage of exoplanet microlensing experts, the Roman Project and the Science Support Center (SSC) have committed to produce an unusually large set of high level data products to enable newcomers to the field to work productively with the data. We will work very closely with the Roman Science Centers, the Roman Project team and the Community Science Collaborations relevant to the GBTDS to develop and test these data products. We will make our photometry, astrometry and event modeling software publicly available and user-friendly to enable broad participation in RGES science. The same is true for our exoplanet yield simulation tools, and this will enable those interested in doing science with the GBTDS to assess how the survey parameters affect their science yield, as well as that of the RGES.

Finally, we will develop a comprehensive plan that will not only seek to establish a culture of inclusiveness, diversity, and equity in the RGES Project Infrastructure Team and the larger microlensing community as a whole, but also include and train early career researchers from other disciplines to exploit the cutting-edge science enabled by the RGES. While the small size of the US exoplanet microlensing community is a challenge for RGES science, it offers an unusual opportunity to help develop a more inclusive astronomical community. We propose to establish a new undergraduate, graduate, and postdoc inclusion program through Howard University to attract promising young scientists from underrepresented backgrounds without significant microlensing experience to study the exoplanet microlensing method with the RGES team. This would prepare them to take leading roles in the analysis of Roman’s exoplanet microlensing data once those data become available.