Key Observing Surveys and Programs
The Nancy Grace Roman Space Telescope is being designed to be capable of executing the survey and observing programs described below, which form Roman’s design reference mission. These represent examples of possible survey designs; the actual implementation of Roman’s core surveys will be defined through an open, community-driven process. Observing time, as well as funding for analyzing Roman archival data, will be competed and selected through future peer reviews.
In addition to the key science themes, Roman will probe a range of additional astrophysical and planetary science topics such as stars in neighboring galaxies, supermassive black holes in faraway galaxies, cosmic nurseries where stars and planets come to life, and small bodies in our solar system. All Roman observations will be publicly available with no period of limited access. For more information on surveys, see the Roman Science Team Community Briefing.
High Latitude Wide Area Survey
The High Latitude Wide Area Survey plans to cover approximately 2000 square degrees of the sky with imaging and low-resolution (grism) spectroscopy, for a total observing time of about two years. The imaging, in four NIR bands (Y, J, H, and F184), is designed to reach J=26.7 AB for point sources. The spectroscopy component is designed to allow the measurement of redshifts for over 15 million sources at redshift 1.1 to 2.8. Imaging and spectroscopic data would support dark energy weak lensing and baryon acoustic oscillation measurements, respectively, and form an invaluable survey for archival research studies on a variety of general astrophysics topics.
High Latitude Time Domain Survey
The three-tiered High Latitude Time Domain Survey includes both imaging and slitless spectroscopy, for a total observing time 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 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 are 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 archival research studies of general astrophysics topics.
Galactic Bulge Time Domain Survey
The Galactic Bulge Time Domain Survey plans to observe multiple fields in the Milky Way’s bulge with WFI, for a total observing time of approximately 1 year. The survey is designed to image the Milky Way's fields every 15 minutes over contiguous 72-days periods ("seasons"), to create highly sampled light curves of 56 million stars brighter than H=21.6 (AB). The survey plans to execute six of such seasons over the mission lifetime, to allow the 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. In addition, the survey will enable the detection of about 20,000 giant planets in short-period orbits from their transit signature. These survey data will also be useful for archival research studies of general astrophysics topics.
Coronagraph Instrument Program
A Coronagraph Instrument 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.
General Astrophysics and Archival Research Programs
General Astrophysics and archival research programs will also be implemented during the five-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 the data. The Coronagraph Instrument will have a Participating Scientist Program upon successful completion of the Technology Demonstration.