Key Observing Surveys and Programs
The Nancy Grace Roman Space Telescope is being designed to be capable of executing the following survey and observing programs. The specific implementation of surveys, the implementation survey teams, and all Guest Observer time will be competed and selected through future peer reviews. The surveys and programs all relate to at least two of the three main science themes of the Roman Space Telescope: measuring dark energy, investigating exoplanets, and great observatory astrophysics and planetary science.
WFI High-Latitude Survey (HLS)
A Wide Field Instrument (WFI) High-Latitude Survey (HLS) will be performed, taking up to 2 years of observations. The HLS will cover approximately 2000 square degrees with imaging and low-resolution (grism) spectroscopy. The imaging, in four NIR bands (Y, J, H, and F184), will reach J=26.7 AB for point sources. The spectroscopy will measure redshifts for over 15 million sources at redshift 1.1 to 2.8. Imaging and spectroscopy will support dark energy weak lensing and baryon acoustic oscillation measurements, respectively, and form an invaluable survey for Guest Investigator archival research studies of general astrophysics topics.
WFI Supernova Survey
A three-tiered WFI supernova survey will perform both imaging and slitless spectroscopy, taking a total of approximately 0.6 years. The imaging survey is designed in three tiers, shallow, medium, and deep, to find supernovae at redshift < 0.4, < 0.8, and < 1.7, respectively. The three tiers will cover approximately 27, 9, and 5 square degrees, respectively, with observations repeated with a cadence of 5 days, in filters Y and J for the shallow tier, and J and H for the medium and deep tier. Spectroscopic observations will be used to fully characterize the type and light curve of a subset of 2700 supernovae, chosen to sample the full redshift range. These survey data will also be useful for Guest Investigator archival research studies of general astrophysics topics.
WFI Bulge Microlensing Survey
A WFI microlensing survey of the Milky Way bulge will be performed with the WFI, taking a total of approximately 1 year. Multiple fields will be imaged every 15 minutes over contiguous 72-day periods ("seasons"), to create highly sampled light curves of 56 million stars brighter than H=21.6 (AB). Six such seasons will be executed over the mission lifetime, resulting in the expected discovery of over 2000 bound planets in the range 0.1-1000 Earth masses and orbital major axes from 0.03 to 30 AU through their microlensing signature. About 20,000 giant planets in short-period orbits will be detected from their transit signature. These survey data will also be useful for Guest Investigator archival research studies of general astrophysics topics.
CGI Coronagraphic Program
A Coronagraph Instrument (CGI) observing program will be performed as part of the Technology Demonstration. The follow-on Participation Scientist Program may focus on discovery and characterization of planets around pre-selected target stars. When a previously known or unknown planet is detected, additional observations may be made for longer periods, with full spectral resolution for planet characterization. Dozens of planets may be targeted in this manner.
Guest Observer (GO) and Guest Investigator (GI) Programs
A WFI GO program and an archival Guest Investigator (GI) program will also be implemented during the 5-year baseline mission. Observations and archival investigations covering all areas of astrophysics will be competitively selected through peer review, in the same spirit as for other NASA Great Observatories. In addition, all Roman observations will be publicly available with no period of limited access, enabling immediate use of survey data for GI programs. The CGI will have a Participating Scientist Program upon successful completion of the Technology Demonstration.