NASA’s Nancy Grace Roman Space Telescope team has released detailed plans for a major survey that will reveal our home galaxy, the Milky Way, in unprecedented detail. In one month of observations spread across two years, the survey will unveil tens of billions of stars and explore previously uncharted structures.
This video begins with a view of the Carina
Nebula — a giant, relatively nearby star-forming region in the southern sky.
Roman will view the entire nebula as well as its surroundings, including a
10,000 light-year-long swath of the spiral arm it resides in. The observation
will offer an unparalleled opportunity to watch how stars grow, interact, and
sculpt their environments, and it’s just one of many thousands of highlights
astronomers are looking forward to from the Galactic Plane Survey NASA’s Nancy Grace
Roman Space Telescope will conduct.
Credit: NASA’s Goddard Space Flight Center
“The Galactic Plane Survey will
revolutionize our understanding of the Milky Way,” said Julie McEnery, Roman’s
senior project scientist at NASA’s Goddard Space Flight Center in Greenbelt,
Maryland. “We’ll be able to explore the mysterious far side of our galaxy and
its star-studded heart. Because of the survey’s breadth and depth, it will be a
scientific mother lode.”
The Galactic Plane Survey is
Roman’s first selected general astrophysics survey — one of many observation programs Roman will do
in addition to its three core surveys and Coronagraph technology demonstration. At least 25% of Roman’s five-year primary mission is
reserved for astronomers worldwide to propose more surveys beyond the core
programs, fully leveraging Roman’s capabilities to conduct groundbreaking
science. Roman is slated to launch by May 2027, but the team is on track for
launch as early as fall 2026.
While ESA’s (European Space
Agency’s) retired Gaia spacecraft mapped around 2 billion Milky Way stars in visible light,
many parts of the galaxy remain hidden by dust. By surveying in infrared light,
Roman will use powerful heat vision that can pierce this veil to see what lies beyond.
“It blows my mind that we will be able to see through the densest part of our galaxy and explore it properly for the first time,” said Rachel Street, a senior scientist at Las Cumbres Observatory in Santa Barbara, California, and a co-chair of the committee that selected the Galactic Plane Survey design.
This infographic describes the 29-day Galactic Plane
Survey that will be conducted by NASA’s Nancy Grace Roman Space Telescope. The
survey’s main component will cover 691 square degrees — a region of sky as
large as around 3,500 full moons — in 22.5 days. Roman will also view a smaller
area — 19 square degrees, the area of 95 full moons — repeatedly for about 5.5
days total to capture things that change over time. The survey’s final
component will image a smattering of even smaller areas, adding up to about 4
square degrees (the area of 20 full moons) and 31 total hours, with Roman’s
full suite of filters and spectroscopic tools. The survey will reveal our home
galaxy in unprecedented detail including many in regions we’ve never been able
to see before because they’re blocked by dust, unveiling tens of billions of
stars and other objects.
Credit: NASA’s Goddard Space Flight Center
The survey will cover nearly 700 square degrees (a region of sky as large
as about 3,500 full moons) along the glowing band of the Milky Way — our
edge-on view of the disk-shaped structure containing most of our galaxy’s
stars, gas, and dust. Scientists expect the survey to map up to 20 billion
stars and detect tiny shifts in their positions with repeated high-resolution
observations. And it will only take 29 days spread over the course of the
mission’s first two years.
Stars are born from parent clouds
of gas and dust. Roman will peer through the haze of these nesting grounds to
see millions of stellar embryos, newborn stars still swaddled in shrouds of
dust, tantrumming toddler stars that flare unpredictably, and young stars that
may have planetary systems forming around them. Astronomers will study stellar
birth rates across a wide range of masses and stitch together videos that show
how stars change over time.
“This survey will study such a huge
number of stars in so many different stellar environments that we’ll be
sampling every phase of a star’s evolution,” Street said.
Observing so many stars in various
stages of early development will shed light on the forces that shape them. Star
formation is like a four way tug-of-war between gravity, radiation, magnetism,
and turbulence. Roman will help us study how these forces influence whether gas
clouds collapse into full-fledged stars, smaller brown dwarfs — in-between
objects that are much heavier than planets but not massive enough to ignite
like stars — or new worlds.
The Galactic Plane Survey by NASA’s Nancy Grace
Roman Space Telescope will scan the densest part of our galaxy, where most of
its stars, gas, and dust reside — the most difficult region to study from our
place inside the Milky Way since we have to look through so much light-blocking
material. Roman’s wide field of view, crisp resolution, and infrared vision
will help astronomers peer through thick bands of dust to chart new galactic
territory.
Credit: NASA’s Goddard Space Flight Center
Some stars are born in enormous
litters called clusters. Roman will study nearly 2,000 young, loosely
bound open clusters to see how the galaxy’s spiral arms trigger star formation. The
survey will also map dozens of ancient, densely packed globular clusters near the center of the galaxy that could help astronomers reconstruct
the Milky Way’s early history.
Comparing Roman’s snapshots of
clusters scattered throughout the galaxy will enable scientists to study nature
versus nurture on a cosmic scale. Because a cluster’s stars generally share the
same age, origin, and chemical makeup, analyzing them allows astronomers to
isolate environmental effects very precisely.
Pulse Check
When they run out of fuel, Sun-like
stars leave behind cores called white
dwarfs and
heavier stars collapse to form neutron stars and black
holes. Roman will
find these stellar embers even when they’re alone thanks to wrinkles in space-time.
Anything that has mass warps the underlying fabric of the universe. When light from a background star passes through the
gravitational well around an intervening object on its journey toward Earth,
its path slightly curves around the object. This phenomenon, called microlensing, can temporarily brighten the star. By studying these signals, astronomers
can learn the mass and size of otherwise invisible foreground objects.
A separate survey
— Roman’s Galactic Bulge Time-Domain Survey — will conduct deep microlensing
observations over a smaller area in the heart of the Milky Way. The Galactic
Plane Survey will conduct repeated observations over a shorter interval but
across the whole center of the galaxy, giving us the first complete view of
this complex galactic environment. An unobscured view of the galaxy’s central
bar will help astronomers answer the question of its origin, and Roman’s videos
of stars in this region will enable us to study some ultratight binary objects
at the very ends of their lives thanks to their interactions with close
companions.
“Compact binaries are particularly
interesting because they’re precursors to gravitational-wave sources,” said
Robert Benjamin, a visiting professor at the University of
Wisconsin-Whitewater, and a co-chair of the committee that selected the
Galactic Plane Survey design. When neutron stars and black holes merge, the
collision is so powerful that it sends ripples through the fabric of space-time. “Scientists want to know more about the pathways
that lead to those mergers.”
Roman’s repeated observations will also
monitor stars that flicker. Ground-based surveys detect thousands of bright
stellar outbursts, but often can’t see the faint, dust-obscured stars that
produce them. Roman will pinpoint the culprits plus take high-resolution
snapshots of the aftermath.
Some stars throb rhythmically, and the
speed of their pulsing is directly linked to their intrinsic brightness. By
comparing their true brightness to how bright they appear from Earth,
astronomers can measure distances across the galaxy. Roman will find these
blinking stars farther away than ever before and track them over time, helping
astronomers improve their cosmic measuring sticks.
“Pairing Roman’s Galactic Plane Survey
with other Milky Way observations will create the best portrait of the galaxy
we’ve ever had,” Benjamin said.
Download additional images and video from NASA’s Scientific
Visualization Studio.
For more information about the Roman Space Telescope, visit: https://www.nasa.gov/roman
Source: NASA Announces Plan to Map Milky Way With Roman Space Telescope - NASA
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