Hubble Survey Sets Up Roman’s Future Look Near Milky Way’s Center
Released: 11 May 2026 10am ID: 2026-201
This large-scale program provides a springboard to help interpret future Roman data.
One of the core community surveys of NASA’s Nancy Grace Roman Space Telescope, the Galactic Bulge Time-Domain Survey, is expected to locate over a thousand exoplanets that orbit far away from their stars, beyond the orbital distance of Earth from the Sun. Although Roman hasn’t launched yet, astronomers already are gathering useful supporting data by utilizing NASA's Hubble Space Telescope, which could assist astronomers in analyzing Roman data...
This survey consists of six 72-day observing seasons during which Roman will take a snapshot every 12 minutes of a large portion of the bulge (approximately 1.7 square degrees of the region, or the area of 8.5 full moons). While it will detect a variety of targets, the survey is optimized to look for a specific type of event known as microlensing.
Article Link:
https://www.stsci.edu/contents/news-releases/2026/news-2026-201.html?utm_source=roman&utm_campaign=inbox_astronomy&utm_id=2026-201#section-id-3
Video Description [4m 7sec]:
This video shows a zoom into the Milky Way’s galactic bulge near the galactic center. As it zooms in, the view changes from the near-infrared 2MASS survey to the VISTA VVV survey (both ground-based). At the conclusion of the zoom, part of the region of the galactic bulge that will be surveyed by Roman’s Galactic Bulge Time-Domain Survey is highlighted with five stacked fields of view. (Roman will also observe a sixth field at the galactic center that is not shown here.)
ED: After watching the video, I'm reminded how little we know. More data is coming in that we cannot keep up with it.
Pic Description Top:
This near-infrared image from the ground-based VISTA VVV Survey shows the galactic bulge near Sagittarius A* (pronounced “A star”), the black hole at the Milky Way’s center. The region, outlined in white, shows five stacked fields of view from NASA’s Nancy Grace Roman Space Telescope that will be observed as part of its Galactic Bulge Time-Domain Survey, one of its three core community surveys. (Roman will also observe a sixth field at the galactic center that is not shown here.) Prior to Roman’s launch, a team of researchers sought to use Hubble to capture the same regions in preparation for potential microlensing events.
Pic Description Mid:
A follow-up observation by NASA’s Hubble Space Telescope shows a field containing a microlensing event that was captured by the Optical Gravitational Lensing Experiment (OGLE) in 2013. This provides an example of how a Hubble image could be used to analyze future microlensing events spotted by NASA’s Nancy Grace Roman Space Telescope.
In gravitational microlensing, the gravity of a foreground object acts as a lens, magnifying and distorting the light of a background star when the two objects align in the sky.
Pic Description Bot:
This graphic illustrates a microlensing event, which occurs when the light from a distant object warps as a mass, such as a star (depicted here) or a stellar-mass black hole, precisely aligns in front of that object. In this image, a red, foreground star intervenes between the telescope, acting as the “lens,” bending, and magnifying the light of the yellow background star. Unlike some gravitational lensing events, which occur at the scale of galaxies or galaxy clusters, microlensing events occur on a much smaller scale, such as that of individual stars. The lensing effect is, therefore, much smaller.
This image also provides a representation of what the background star would look like to a telescope in a microlensing event. Because of the curvature of space around the background star (represented by the white arrows that curve around it in the image), the background star appears to increase in brightness as the event begins before decreasing in apparent brightness as it falls out of alignment. The graph at bottom plots the apparent brightness of the background star over time.
Credits: NASA, ESA, Alyssa Pagan (STScI), Sean Terry (UMD), Jay Anderson (STScI), Joyce Kang (STScI)