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By NASA
Hubble Space Telescope Home NASA’s Hubble Sees… Hubble Space Telescope Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts E-books Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More Online Activities 5 Min Read NASA’s Hubble Sees Aftermath of Galaxy’s Scrape with Milky Way
This artist’s concept shows a closeup of the Large Magellanic Cloud, a dwarf galaxy that is one of the Milky Way galaxy’s nearest neighbors. Credits:
NASA, ESA, Ralf Crawford (STScI) A story of survival is unfolding at the outer reaches of our galaxy, and NASA’s Hubble Space Telescope is witnessing the saga.
The Large Magellanic Cloud, also called the LMC, is one of the Milky Way galaxy’s nearest neighbors. This dwarf galaxy looms large on the southern nighttime sky at 20 times the apparent diameter of the full Moon.
Many researchers theorize that the LMC is not in orbit around our galaxy, but is just passing by. These scientists think that the LMC has just completed its closest approach to the much more massive Milky Way. This passage has blown away most of the spherical halo of gas that surrounds the LMC.
Now, for the first time, astronomers been able to measure the size of the LMC’s halo – something they could do only with Hubble. In a new study to be published in The Astrophysical Journal Letters, researchers were surprised to find that it is so extremely small, about 50,000 light-years across. That’s around 10 times smaller than halos of other galaxies that are the LMC’s mass. Its compactness tells the story of its encounter with the Milky Way.
“The LMC is a survivor,” said Andrew Fox of AURA/STScI for the European Space Agency in Baltimore, who was principal investigator on the observations. “Even though it’s lost a lot of its gas, it’s got enough left to keep forming new stars. So new star-forming regions can still be created. A smaller galaxy wouldn’t have lasted – there would be no gas left, just a collection of aging red stars.”
This artist’s concept shows the Large Magellanic Cloud, or LMC, in the foreground as it passes through the gaseous halo of the much more massive Milky Way galaxy. The encounter has blown away most of the spherical halo of gas that surrounds the LMC, as illustrated by the trailing gas stream reminiscent of a comet’s tail. Still, a compact halo remains, and scientists do not expect this residual halo to be lost. The team surveyed the halo by using the background light of 28 quasars, an exceptionally bright type of active galactic nucleus that shines across the universe like a lighthouse beacon. Their light allows scientists to “see” the intervening halo gas indirectly through the absorption of the background light. The lines represent the Hubble Space Telescope’s view from its orbit around Earth to the distant quasars through the LMC’s gas. NASA, ESA, Ralf Crawford (STScI)
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Though quite a bit worse for wear, the LMC still retains a compact, stubby halo of gas – something that it wouldn’t have been able to hold onto gravitationally had it been less massive. The LMC is 10 percent the mass of the Milky Way, making it heftier than most dwarf galaxies.
“Because of the Milky Way’s own giant halo, the LMC’s gas is getting truncated, or quenched,” explained STScI’s Sapna Mishra, the lead author on the paper chronicling this discovery. “But even with this catastrophic interaction with the Milky Way, the LMC is able to retain 10 percent of its halo because of its high mass.”
A Gigantic Hair Dryer
Most of the LMC’s halo was blown away due to a phenomenon called ram-pressure stripping. The dense environment of the Milky Way pushes back against the incoming LMC and creates a wake of gas trailing the dwarf galaxy – like the tail of a comet.
“I like to think of the Milky Way as this giant hairdryer, and it’s blowing gas off the LMC as it comes into us,” said Fox. “The Milky Way is pushing back so forcefully that the ram pressure has stripped off most of the original mass of the LMC’s halo. There’s only a little bit left, and it’s this small, compact leftover that we’re seeing now.”
As the ram pressure pushes away much of the LMC’s halo, the gas slows down and eventually will rain into the Milky Way. But because the LMC has just gotten past its closest approach to the Milky Way and is moving outward into deep space again, scientists do not expect the whole halo will be lost.
Only with Hubble
To conduct this study, the research team analyzed ultraviolet observations from the Mikulski Archive for Space Telescopes at STScI. Most ultraviolet light is blocked by the Earth’s atmosphere, so it cannot be observed with ground-based telescopes. Hubble is the only current space telescope tuned to detect these wavelengths of light, so this study was only possible with Hubble.
The team surveyed the halo by using the background light of 28 bright quasars. The brightest type of active galactic nucleus, quasars are believed to be powered by supermassive black holes. Shining like lighthouse beacons, they allow scientists to “see” the intervening halo gas indirectly through the absorption of the background light. Quasars reside throughout the universe at extreme distances from our galaxy.
This artist’s concept illustrates the Large Magellanic Cloud’s (LMC’s) encounter with the Milky Way galaxy’s gaseous halo. In the top panel, at the middle of the right side, the LMC begins crashing through our galaxy’s much more massive halo. The bright purple bow shock represents the leading edge of the LMC’s halo, which is being compressed as the Milky Way’s halo pushes back against the incoming LMC. In the middle panel, part of the halo is being stripped and blown back into a streaming tail of gas that eventually will rain into the Milky Way. The bottom panel shows the progression of this interaction, as the LMC’s comet-like tail becomes more defined. A compact LMC halo remains. Because the LMC is just past its closest approach to the Milky Way and is moving outward into deep space again, scientists do not expect the residual halo will be lost. NASA, ESA, Ralf Crawford (STScI)
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The scientists used data from Hubble’s Cosmic Origins Spectrograph (COS) to detect the presence of the halo’s gas by the way it absorbs certain colors of light from background quasars. A spectrograph breaks light into its component wavelengths to reveal clues to the object’s state, temperature, speed, quantity, distance, and composition. With COS, they measured the velocity of the gas around the LMC, which allowed them to determine the size of the halo.
Because of its mass and proximity to the Milky Way, the LMC is a unique astrophysics laboratory. Seeing the LMC’s interplay with our galaxy helps scientists understand what happened in the early universe, when galaxies were closer together. It also shows just how messy and complicated the process of galaxy interaction is.
Looking to the Future
The team will next study the front side of the LMC’s halo, an area that has not yet been explored.
“In this new program, we are going to probe five sightlines in the region where the LMC’s halo and the Milky Way’s halo are colliding,” said co-author Scott Lucchini of the Center for Astrophysics | Harvard & Smithsonian. “This is the location where the halos are compressed, like two balloons pushing against each other.”
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contacts:
Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
Ann Jenkins, Ray Villard
Space Telescope Science Institute, Baltimore, MD
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Last Updated Nov 14, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Astrophysics Astrophysics Division Galaxies Hubble Space Telescope Irregular Galaxies Spiral Galaxies The Milky Way Keep Exploring Discover More Topics From NASA
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Galaxy Details and Mergers
Hubble’s Galaxies
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By NASA
This photo shows the Optical Telescope Assembly for NASA’s Nancy Grace Roman Space Telescope, which was recently delivered to the largest clean room at the agency’s Goddard Space Flight Center in Greenbelt, Md.NASA/Chris Gunn NASA’s Nancy Grace Roman Space Telescope is one giant step closer to unlocking the mysteries of the universe. The mission has now received its final major delivery: the Optical Telescope Assembly, which includes a 7.9-foot (2.4-meter) primary mirror, nine additional mirrors, and supporting structures and electronics. The assembly was delivered Nov. 7. to the largest clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, where the observatory is being built.
The telescope will focus cosmic light and send it to Roman’s instruments, revealing many billions of objects strewn throughout space and time. Using the mission’s Wide Field Instrument, a 300-megapixel infrared camera, astronomers will survey the cosmos all the way from the outskirts of our solar system toward the edge of the observable universe. Scientists will use Roman’s Coronagraph Instrument to test new technologies for dimming host stars to image planets and dusty disks around them in far better detail than ever before.
“We have a top-notch telescope that’s well aligned and has great optical performance at the cold temperatures it will see in space,” said Bente Eegholm, optics lead for Roman’s Optical Telescope Assembly at NASA Goddard. “I am now looking forward to the next phase where the telescope and instruments will be put together to form the Roman observatory.”
In this photo, optical engineer Bente Eegholm inspects the surface of the primary mirror for NASA’s Nancy Grace Roman Space Telescope. This 7.9-foot (2.4-meter) mirror is a major component of the Optical Telescope Assembly, which also contains nine additional mirrors and supporting structures and electronics.NASA/Chris Gunn Designed and built by L3Harris Technologies in Rochester, New York, the assembly incorporates key optics (including the primary mirror) that were made available to NASA by the National Reconnaissance Office. The team at L3Harris then reshaped the mirror and built upon the inherited hardware to ensure it would meet Roman’s specifications for expansive, sensitive infrared observations.
“The telescope will be the foundation of all of the science Roman will do, so its design and performance are among the largest factors in the mission’s survey capability,” said Josh Abel, lead Optical Telescope Assembly systems engineer at NASA Goddard.
The team at Goddard worked closely with L3Harris to ensure these stringent requirements were met and that the telescope assembly will integrate smoothly into the rest of the Roman observatory.
The assembly’s design and performance will largely determine the quality of the mission’s results, so the manufacturing and testing processes were extremely rigorous. Each optical component was tested individually prior to being assembled and assessed together earlier this year. The tests helped ensure that the alignment of the telescope’s mirrors will change as expected when the telescope reaches its operating temperature in space.
Then, the telescope was put through tests simulating the extreme shaking and intense sound waves associated with launch. Engineers also made sure that tiny components called actuators, which will adjust some of the mirrors in space, move as predicted. And the team measured gases released from the assembly as it transitioned from normal air pressure to a vacuum –– the same phenomenon that has led astronauts to report that space smells gunpowdery or metallic. If not carefully controlled, these gases could contaminate the telescope or instruments.
Upon arrival at NASA’s Goddard Space Flight Center, the Optical Telescope Assembly for the agency’s Nancy Grace Roman Space Telescope was lifted out of the shipping fixture and placed with other mission hardware in Goddard’s largest clean room. Now, it will be installed onto Roman’s Instrument Carrier, a structure that will keep the telescope and Roman’s two instruments optically aligned. The assembly’s electronics box –– essentially the telescope’s brain –– will be mounted within the spacecraft along with Roman’s other electronics.NASA/Chris Gunn Finally, the telescope underwent a month-long thermal vacuum test to ensure it will withstand the temperature and pressure environment of space. The team closely monitored it during cold operating conditions to ensure the telescope’s temperature will remain constant to within a fraction of a degree. Holding the temperature constant allows the telescope to remain in stable focus, making Roman’s high-resolution images consistently sharp. Nearly 100 heaters on the telescope will help keep all parts of it at a very stable temperature.
“It is very difficult to design and build a system to hold temperatures to such a tight stability, and the telescope performed exceptionally,” said Christine Cottingham, thermal lead for Roman’s Optical Telescope Assembly at NASA Goddard.
Now that the assembly has arrived at Goddard, it will be installed onto Roman’s Instrument Carrier, a structure that will keep the telescope and Roman’s two instruments optically aligned. The assembly’s electronics box –– essentially the telescope’s brain –– will be mounted within the spacecraft along with Roman’s other electronics.
With this milestone, Roman remains on track for launch by May 2027.
“Congratulations to the team on this stellar accomplishment!” said J. Scott Smith, the assembly’s telescope manager at NASA Goddard. “The completion of the telescope marks the end of an epoch and incredible journey for this team, and yet only a chapter in building Roman. The team’s efforts have advanced technology and ignited the imaginations of those who dream of exploring the stars.”
Virtually tour an interactive version of the telescope The Nancy Grace Roman Space Telescope is managed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with participation by NASA’s Jet Propulsion Laboratory and Caltech/IPAC in Southern California, the Space Telescope Science Institute in Baltimore, and a science team comprising scientists from various research institutions. The primary industrial partners are BAE Systems Inc. in Boulder, Colorado; L3Harris Technologies in Rochester, New York; and Teledyne Scientific & Imaging in Thousand Oaks, California.
By Ashley Balzer
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, Md.
claire.andreoli@nasa.gov
301-286-1940
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Last Updated Nov 14, 2024 EditorAshley BalzerContactAshley Balzerashley.m.balzer@nasa.govLocationGoddard Space Flight Center Related Terms
Nancy Grace Roman Space Telescope Exoplanets Goddard Space Flight Center The Universe View the full article
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By European Space Agency
12 November 2024 marks the start of a new year on Mars. At exactly 10:32 CET/09:32 UTC on Earth, the Red Planet begins a new orbit around our Sun.
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By NASA
ESA/Hubble & NASA, O. Fox, L. Jenkins, S. Van Dyk, A. Filippenko, J. Lee and the PHANGS-HST Team, D. de Martin (ESA/Hubble), M. Zamani (ESA/Hubble) This NASA/ESA Hubble Space Telescope image features NGC 1672, a barred spiral galaxy located 49 million light-years from Earth in the constellation Dorado. This galaxy is a multi-talented light show, showing off an impressive array of different celestial lights. Like any spiral galaxy, shining stars fill its disk, giving the galaxy a beautiful glow. Along its two large arms, bubbles of hydrogen gas shine in a striking red light fueled by radiation from infant stars shrouded within. Near the galaxy’s center are some particularly spectacular stars embedded within a ring of hot gas. These newly formed and extremely hot stars emit powerful X-rays. Closer in, at the galaxy’s very center, sits an even brighter source of X-rays, an active galactic nucleus. This X-ray powerhouse makes NGC 1672 a Seyfert galaxy. It forms as a result of heated matter swirling in the accretion disk around NGC 1672’s supermassive black hole.
See more images of NGC 1672.
Image credit: ESA/Hubble & NASA, O. Fox, L. Jenkins, S. Van Dyk, A. Filippenko, J. Lee and the PHANGS-HST Team, D. de Martin (ESA/Hubble), M. Zamani (ESA/Hubble)
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By NASA
Hubble Space Telescope Home Hubble Captures a Galaxy with… Missions Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts E-books Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More Online Activities 2 min read
Hubble Captures a Galaxy with Many Lights
This NASA/ESA Hubble Space Telescope image captures the spiral galaxy NGC 1672 with a supernova. ESA/Hubble & NASA, O. Fox, L. Jenkins, S. Van Dyk, A. Filippenko, J. Lee and the PHANGS-HST Team, D. de Martin (ESA/Hubble), M. Zamani (ESA/Hubble)
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This NASA/ESA Hubble Space Telescope image features NGC 1672, a barred spiral galaxy located 49 million light-years from Earth in the constellation Dorado. This galaxy is a multi-talented light show, showing off an impressive array of different celestial lights. Like any spiral galaxy, shining stars fill its disk, giving the galaxy a beautiful glow. Along its two large arms, bubbles of hydrogen gas shine in a striking red light fueled by radiation from infant stars shrouded within. Near the galaxy’s center are some particularly spectacular stars embedded within a ring of hot gas. These newly formed and extremely hot stars emit powerful X-rays. Closer in, at the galaxy’s very center, sits an even brighter source of X-rays, an active galactic nucleus. This X-ray powerhouse makes NGC 1672 a Seyfert galaxy. It forms as a result of heated matter swirling in the accretion disk around NGC 1672’s supermassive black hole.
Image Before/After Along with its bright young stars and X-ray core, a highlight of this image is the most fleeting and temporary of lights: a supernova, visible in just one of the six Hubble images that make up this composite. Supernova SN 2017GAX was a Type I supernova caused by the core-collapse and subsequent explosion of a giant star that went from invisible to a new light in the sky in just a matter of days. In the image above, the supernova is already fading and is visible as a small green dot just below the crook of the spiral arm on the right side. Astronomers wanted to look for any companion star that the supernova progenitor may have had — something impossible to spot beside a live supernova — so they purposefully captured this image of the fading supernova.
Recently, NGC 1672 was also among a crop of galaxies imaged with the NASA/ESA/CSA James Webb Space Telescope, showing the ring of gas and the structure of dust in its spiral arms. The image below compares the Webb image with Hubble’s image.
Image Before/After Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
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Last Updated Nov 08, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Astrophysics Astrophysics Division Galaxies Goddard Space Flight Center Hubble Space Telescope Missions Spiral Galaxies Stars Supernovae The Universe Keep Exploring Discover More Topics From Hubble
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Hubble’s Galaxies
Hubble Focus: Galaxies through Space and Time
Hubble Focus: Galaxies through Space and Time
Hubble’s Partners in Science
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