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Hubble Space Telescope Home Hubble Examines a Busy… 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 Examines a Busy Galactic Center
This NASA/ESA Hubble Space Telescope image features the active spiral galaxy IC 4709. ESA/Hubble & NASA, M. Koss, A, Barth This NASA/ESA Hubble Space Telescope image features the spiral galaxy IC 4709a located around 240 million light-years away in the southern constellation Telescopium. Hubble beautifully captures its faint halo and swirling disk filled with stars and dust bands. The compact region at its core might be the most remarkable sight. It holds an active galactic nucleus (AGN).
If IC 4709’s core just held stars, it wouldn’t be nearly as bright. Instead, it hosts a gargantuan black hole, 65 million times more massive than our Sun. A disk of gas spirals around and eventually into this black hole, crashing together and heating up as it spins. It reaches such high temperatures that it emits vast quantities of electromagnetic radiation, from infrared to visible to ultraviolet light and X-rays. A lane of dark dust, just visible at the center of the galaxy in the image above, obscures the AGN in IC 4709. The dust lane blocks any visible light emission from the nucleus itself. Hubble’s spectacular resolution, however, gives astronomers a detailed view of the interaction between the quite small AGN and its host galaxy. This is essential to understanding supermassive black holes in galaxies much more distant than IC 4709, where resolving such fine details is not possible.
This image incorporates data from two Hubble surveys of nearby AGNs originally identified by NASA’s Swift telescope. There are plans for Swift to collect new data on these galaxies. Swift houses three multiwavelength telescopes, collecting data in visible, ultraviolet, X-ray, and gamma-ray light. Its X-ray component will allow SWIFT to directly see the X-rays from IC 4709’s AGN breaking through the obscuring dust. ESA’s Euclid telescope — currently surveying the dark universe in optical and infrared light — will also image IC 4709 and other local AGNs. Their data, along with Hubble’s, provides astronomers with complementary views across the electromagnetic spectrum. Such views are key to fully research and better understand black holes and their influence on their host galaxies.
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Last Updated Sep 05, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
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By NASA
A galactic halo is a loose collection of stars that extends 15 to 20 times beyond the radius of the brightest part of the galaxy. One of the few galaxies with a well-studied stellar halo is our neighbor, Andromeda, depicted here in the graphic. The stellar halo is illustrated with exaggerated brightness and density to show how far it extends. When the Nancy Grace Roman Space Telescope launches, it will be able to use its wide field of view to comprehensively image many more stellar halos of more distant galaxies.
NASA, Ralf Crawford (STScI) The universe is a dynamic, ever-changing place where galaxies are dancing, merging together, and shifting appearance. Unfortunately, because these changes take millions or billions of years, telescopes can only provide snapshots, squeezed into a human lifetime.
However, galaxies leave behind clues to their history and how they came to be. NASA’s upcoming Nancy Grace Roman Space Telescope will have the capacity to look for these fossils of galaxy formation with high-resolution imaging of galaxies in the nearby universe.
Astronomers, through a grant from NASA, are designing a set of possible observations called RINGS (the Roman Infrared Nearby Galaxies Survey) that would collect these remarkable images, and the team is producing publicly available tools that the astronomy community can use once Roman launches and starts taking data. The RINGS survey is a preliminary concept that may or may not be implemented during Roman’s science mission.
Roman is uniquely prepared for RINGS due to its resolution akin to NASA’s Hubble Space Telescope and its wide field of view – – 200 times that of Hubble in the infrared – – making it a sky survey telescope that complements Hubble’s narrow-field capabilities.
Galactic Archaeologists
Scientists can only look at brief instances in the lives of evolving galaxies that eventually lead to the fully formed galaxies around us today. As a result, galaxy formation can be difficult to track.
Luckily, galaxies leave behind hints of their evolution in their stellar structures, almost like how organisms on Earth can leave behind imprints in rock. These galactic “fossils” are groups of ancient stars that hold the history of the galaxy’s formation and evolution, including the chemistry of the galaxy when those stars formed.
These cosmic fossils are of particular interest to Robyn Sanderson, the deputy principal investigator of RINGS at the University of Pennsylvania in Philadelphia. She describes the process of analyzing stellar structures in galaxies as “like going through an excavation and trying to sort out bones and put them back together.”
Roman’s high resolution will allow scientists to pick out these galactic fossils, using structures ranging from long tidal tails on a galaxy’s outskirts to stellar streams within the galaxy. These large-scale structures, which Roman is uniquely capable of capturing, can give clues to a galaxy’s merger history. The goal, says Sanderson, is to “reassemble these fossils in order to look back in time and understand how these galaxies came to be.”
Shedding Light on Dark Matter
RINGS will also enable further investigations of one of the most mysterious substances in the universe: dark matter, an invisible form of matter that makes up most of a galaxy’s mass. A particularly useful class of objects for testing dark matter theories are ultra-faint dwarf galaxies. According to Raja GuhaThakurta of the University of California, Santa Cruz, “Ultra faint dwarf galaxies are so dark matter-dominated that they have very little normal matter for star formation. With so few stars being created, ultra-faint galaxies can essentially be seen as pure blobs of dark matter to study.”
Roman, thanks to its large field of view and high resolution, will observe these ultra-faint galaxies to help test multiple theories of dark matter. With these new data, the astronomical community will come closer to finding the truth about this unobservable dark matter that vastly outweighs visible matter: dark matter makes up about 80% of the universe’s matter while normal matter comprises the remaining 20%.
Ultra-faint galaxies are far from the only test of dark matter. Often, just looking in an average-sized galaxy’s backyard is enough. Structures in the halo of stars surrounding a galaxy often give hints to the amount of dark matter present. However, due to the sheer size of galactic halos (they are often 15-20 times as big as the galaxy itself), current telescopes are deeply inefficient at observing them.
At the moment, the only fully resolved galactic halos scientists have to go on are our own Milky Way and Andromeda, our neighbor galaxy. Ben Williams, the principal investigator of RINGS at the University of Washington in Seattle, describes how Roman’s power will amend this problem: “We only have reliable measurements of the Milky Way and Andromeda, because those are close enough that we can get measurements of a large number of stars distributed across their stellar halos. So, with Roman, all of a sudden we’ll have 100 or more of these fully resolved galaxies.”
When Roman launches by May 2027, it is expected to fundamentally alter how scientists understand galaxies. In the process, it will shed some light on our own home galaxy. The Milky Way is easy to study up close, but we do not have a large enough selfie stick to take a photo of our entire galaxy and its surrounding halo. RINGS shows what Roman is capable of should such a survey be approved. By studying the nearby universe, RINGS can examine galaxies similar in size and age to the Milky Way, and shed light on how we came to be here.
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 Patt Molinari
Space Telescope Science Institute, Baltimore, Md.
Media contact:
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Ann Jenkins
Space Telescope Science Institute, Baltimore, Md.
Christine Pulliam
Space Telescope Science Institute, Baltimore, Md.
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5 min read NASA Telescope to Help Untangle Galaxy Growth, Dark Matter Makeup
Article 2 years ago 5 min read Millions of Galaxies Emerge in New Simulated Images From NASA’s Roman
Article 1 year ago 5 min read How NASA’s Roman Space Telescope Will Rewind the Universe
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Last Updated Aug 29, 2024 EditorAshley BalzerContactAshley Balzerashley.m.balzer@nasa.govLocationGoddard Space Flight Center Related Terms
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By NASA
This NASA/ESA Hubble Space Telescope image reveals the galaxy LEDA 857074. ESA/Hubble & NASA, I. Chilingari The subject of this NASA/ESA Hubble Space Telescope image is situated in the Perseus Cluster, also known as Abell 426, 320 million light-years from Earth. It’s a barred spiral galaxy known as MCG+07-07-072, seen here among a number of photobombing stars that are much closer to Earth than it is.
MCG+07-07-072 has quite an unusual shape for a spiral galaxy, with thin arms emerging from the ends of its barred core to draw a near-circle around its disk. It is classified as an SBc(r) galaxy: the c denotes that its two spiral arms are loosely wound, each only performing a half-turn around the galaxy, and the (r) is for the ring-like structure they create.
Rings in galaxies come in quite a few forms, from merely uncommon, to rare and scientifically important! Lenticular galaxies are a type that sit between elliptical and spiral galaxies. They feature a large disk, unlike an elliptical galaxy, but lack any spiral arms. Lenticular means lens-shaped, and these galaxies often feature ring-like shapes in their disks.
Meanwhile, the classification of “ring galaxy” is reserved for peculiar galaxies with a round ring of gas and star formation, much like spiral arms look, but completely disconnected from the galactic nucleus — or even without any visible nucleus! They’re thought to be formed in galactic collisions. Finally, there are the famous gravitational lenses, where the ring is in fact a distorted image of a distant, background galaxy, formed by the ‘lens’ galaxy bending light around it. Ring-shaped images, called Einstein rings, only form when the lensing and imaged galaxies are perfectly aligned.
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By NASA
NASA/CXC/M.Weiss By using new data from NASA’s Chandra X-ray Observatory and Neil Gehrels Swift Observatory as well as ESA’s XMM-Newton, a team of researchers have made important headway in understanding how — and when — a supermassive black hole obtains and then consumes material, as described in our latest press release.
This artist’s impression shows a star that has partially been disrupted by such a black hole in the system known as AT2018fyk. The supermassive black hole in AT2018fyk — with about 50 million times more mass than the sun — is in the center of a galaxy located about 860 million light-years from Earth.
Astronomers have determined that a star is on a highly elliptical orbit around the black hole in AT2018fyk so that its point of farthest approach from the black hole is much larger than its closest. During its closest approach, tidal forces from the black hole pull some material from the star, producing two tidal tails of “stellar debris”.
The illustration shows a point in the orbit soon after the star is partially destroyed, when the tidal tails are still in close proximity to the star. Later in the star’s orbit, the disrupted material returns to the black hole and loses energy, leading to a large increase in X-ray brightness occurring later in the orbit (not shown here). This process repeats each time the star returns to its point of closest approach, which is approximately every 3.5 years. The illustration depicts the star during its second orbit, and the disk of X-ray emitting gas around the black hole that is produced as a byproduct of the first tidal encounter.
Researchers took note of AT2018fyk in 2018 when the optical ground-based survey ASAS-SN detected that the system had become much brighter. After observing it with NASA’s NICER and Chandra, and XMM-Newton, researchers determined that the surge in brightness came from a “tidal disruption event,” or TDE, which signals that a star was completely torn apart and partially ingested after flying too close to a black hole. Chandra data of AT2018fyk is shown in the inset of an optical image of a wider field-of-view.
X-ray: NASA/SAO/Kavli Inst. at MIT/D.R. Pasham; Optical: NSF/Legacy Survey/SDSS When material from the destroyed star approached close to the black hole, it got hotter and produced X-ray and ultraviolet (UV) light. These signals then faded, agreeing with the idea that nothing was left of the star for the black hole to digest.
However, about two years later, the X-ray and UV light from the galaxy got much brighter again. This meant, according to astronomers, that the star likely survived the initial gravitational grab by the black hole and then entered a highly elliptical orbit with the black hole. During its second close approach to the black hole, more material was pulled off and produced more X-ray and UV light.
Based on what they had learned about the star and its orbit, a team of astronomers predicted that the black hole’s second meal would end in August 2023 and applied for Chandra observing time to check. Chandra observations on August 14, 2023, indeed showed the telltale sign of the black hole feeding coming to an end with a sudden drop in X-rays. The researchers also obtained a better estimate of how long it takes the star to complete an orbit, and predicted future mealtimes for the black hole.
A paper describing these results appears in the August 14, 2024 issue of The Astrophysical Journal and is available online. The authors are Dheeraj Passam (Massachusetts Institute of Technology), Eric Coughlin (Syracuse University), Muryel Guolo (Johns Hopkins University), Thomas Wevers (Space Telescope Science Institute), Chris Nixon (University of Leeds, UK), Jason Hinkle (University of Hawaii at Manoa), and Ananaya Bandopadhyay (Syracuse).
NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science from Cambridge Massachusetts and flight operations from Burlington, Massachusetts.
Read more from NASA’s Chandra X-ray Observatory.
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Visual Description:
In this digital illustration, a star sheds stellar debris as it orbits a supermassive black hole. This artist’s impression represents the center of a galaxy about 860 million light-years from Earth.
The supermassive black hole sits at our upper left. It resembles an irregular, pitch-black sphere at the heart of an almond-shaped pocket of swirling sand and dirt. Though gritty in texture, the swirling brown and grey pocket is actually a disk of hot gas.
Near our lower right is the orbiting star. In this illustration, the star is relatively close to us, with the black hole far behind it. The star is a blue-white ball that, from this perspective, appears slightly larger than the distant black hole.
Two tapered streaks peel off of the glowing star like the pulled-back corners of a smile. These streaks represent tidal tails of stellar debris; material pulled from the surface of the star by the gravity of the black hole. This partial destruction of the star occurs every 3.5 years, when the star’s orbit brings it closest to the supermassive black hole.
During the orbit, the stellar debris from the tidal tails is ingested by the black hole. A byproduct of this digestion is the X-ray gas which swirls in a disk around the black hole.
At the upper left of the grid is an image of the distant galaxy cluster known as MACS J0416. Here, the blackness of space is packed with glowing dots and tiny shapes, in whites, purples, oranges, golds, and reds, each a distinct galaxy. Upon close inspection (and with a great deal of zooming in!) the spiraling arms of some of the seemingly tiny galaxies are revealed in this highly detailed image. Gently arched across the middle of the frame is a soft band of purple; a reservoir of superheated gas detected by Chandra.
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By NASA
5 Min Read NASA Optical Navigation Tech Could Streamline Planetary Exploration
Optical navigation technology could help astronauts and robots find their ways using data from cameras and other sensors. Credits: NASA As astronauts and rovers explore uncharted worlds, finding new ways of navigating these bodies is essential in the absence of traditional navigation systems like GPS. Optical navigation relying on data from cameras and other sensors can help spacecraft — and in some cases, astronauts themselves — find their way in areas that would be difficult to navigate with the naked eye. Three NASA researchers are pushing optical navigation tech further, by making cutting edge advancements in 3D environment modeling, navigation using photography, and deep learning image analysis. In a dim, barren landscape like the surface of the Moon, it can be easy to get lost. With few discernable landmarks to navigate with the naked eye, astronauts and rovers must rely on other means to plot a course.
As NASA pursues its Moon to Mars missions, encompassing exploration of the lunar surface and the first steps on the Red Planet, finding novel and efficient ways of navigating these new terrains will be essential. That’s where optical navigation comes in — a technology that helps map out new areas using sensor data.
NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is a leading developer of optical navigation technology. For example, GIANT (the Goddard Image Analysis and Navigation Tool) helped guide the OSIRIS-REx mission to a safe sample collection at asteroid Bennu by generating 3D maps of the surface and calculating precise distances to targets.
Now, three research teams at Goddard are pushing optical navigation technology even further.
Virtual World Development
Chris Gnam, an intern at NASA Goddard, leads development on a modeling engine called Vira that already renders large, 3D environments about 100 times faster than GIANT. These digital environments can be used to evaluate potential landing areas, simulate solar radiation, and more.
While consumer-grade graphics engines, like those used for video game development, quickly render large environments, most cannot provide the detail necessary for scientific analysis. For scientists planning a planetary landing, every detail is critical.
Vira can quickly and efficiently render an environment in great detail.NASA “Vira combines the speed and efficiency of consumer graphics modelers with the scientific accuracy of GIANT,” Gnam said. “This tool will allow scientists to quickly model complex environments like planetary surfaces.”
The Vira modeling engine is being used to assist with the development of LuNaMaps (Lunar Navigation Maps). This project seeks to improve the quality of maps of the lunar South Pole region which are a key exploration target of NASA’s Artemis missions.
Vira also uses ray tracing to model how light will behave in a simulated environment. While ray tracing is often used in video game development, Vira utilizes it to model solar radiation pressure, which refers to changes in momentum to a spacecraft caused by sunlight.
Vira can accurately render indirect lighting, which is when an area is still lit up even though it is not directly facing a light source.NASA Find Your Way with a Photo
Another team at Goddard is developing a tool to enable navigation based on images of the horizon. Andrew Liounis, an optical navigation product design lead, leads the team, working alongside NASA Interns Andrew Tennenbaum and Will Driessen, as well as Alvin Yew, the gas processing lead for NASA’s DAVINCI mission.
An astronaut or rover using this algorithm could take one picture of the horizon, which the program would compare to a map of the explored area. The algorithm would then output the estimated location of where the photo was taken.
Using one photo, the algorithm can output with accuracy around hundreds of feet. Current work is attempting to prove that using two or more pictures, the algorithm can pinpoint the location with accuracy around tens of feet.
“We take the data points from the image and compare them to the data points on a map of the area,” Liounis explained. “It’s almost like how GPS uses triangulation, but instead of having multiple observers to triangulate one object, you have multiple observations from a single observer, so we’re figuring out where the lines of sight intersect.”
This type of technology could be useful for lunar exploration, where it is difficult to rely on GPS signals for location determination.
A Visual Perception Algorithm to Detect Craters
To automate optical navigation and visual perception processes, Goddard intern Timothy Chase is developing a programming tool called GAVIN (Goddard AI Verification and Integration) Tool Suit.
This tool helps build deep learning models, a type of machine learning algorithm that is trained to process inputs like a human brain. In addition to developing the tool itself, Chase and his team are building a deep learning algorithm using GAVIN that will identify craters in poorly lit areas, such as the Moon.
“As we’re developing GAVIN, we want to test it out,” Chase explained. “This model that will identify craters in low-light bodies will not only help us learn how to improve GAVIN, but it will also prove useful for missions like Artemis, which will see astronauts exploring the Moon’s south pole region — a dark area with large craters — for the first time.”
As NASA continues to explore previously uncharted areas of our solar system, technologies like these could help make planetary exploration at least a little bit simpler. Whether by developing detailed 3D maps of new worlds, navigating with photos, or building deep learning algorithms, the work of these teams could bring the ease of Earth navigation to new worlds.
By Matthew Kaufman
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Aug 07, 2024 EditorRob GarnerContactRob Garnerrob.garner@nasa.govLocationGoddard Space Flight Center Related Terms
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