Understanding the nature of dark energy
The Nancy Grace Roman Space Telescope Supernova Survey (ROMAN) is the NASA's next large flagship mission due for launch between October 2026 and early 2027. ROMAN is based on an existing 2.4 m wide field-of-view primary mirror and will carry two scientific instruments: the Coronagraphic Instrument (CGI), a high-contrast, small field-of-view camera and spectrometer covering visible and near-infrared (NIR) wavelengths using novel starlight-suppression technology; and the Wide-Field Instrument (WFI), a 300.8-megapixel multi-band visible and NIR camera, covering a 0.28 sq. deg. field- of-view, 100 times larger than imaging cameras on the HST. One of the mission's key objectives is to determine the expansion history of the universe and to test possible explanations of its apparent acceleration, including dark energy and modification to general relativity. To do so, ROMAN will utilize WFI to conduct two generation-defining core community surveys: the High-Latitude Wide Area Survey for weak lensing and large-scale structure studies, and the High-Latitude Time Domain Survey (HLTDS) in order to enable the discovery and follow-up of SNe Ia up to 𝑧~2.5 and with unparalleled precision and statistical volume.
A NASA mission to discover the furthest supernovae ever observed
ROMAN will obtain observations of the furthest supernovae ever observed (z~2.5), whose light we see now but was emitted when the Universe was only 2,000 million years old. Combined with the Vera Rubin observatory Legacy Survey of Space and Time (LSST), and the low-redshift La Silla Southern Supernova Survey (LS4), will build the most powerful SN Hubble-Lemaître diagram ever constructed, both in the terms of the number of SN and the extended redshift range, yielding a ∼1% measurement in the dark energy equation of state parameter, 𝑤_0, and a ∼10% measurement in its evolution with cosmic time, 𝑤_a.
Meet the senior researcher who leads our participation in the ROMAN mission.
