Members Can Post Anonymously On This Site
NASA’s Fermi Detects Surprise Gamma-Ray Feature Beyond Our Galaxy
-
Similar Topics
-
By NASA
4 min read
NASA’s Fermi Finds New Feature in Brightest Gamma-Ray Burst Yet Seen
In October 2022, astronomers were stunned by what was quickly dubbed the BOAT — the brightest-of-all-time gamma-ray burst (GRB). Now an international science team reports that data from NASA’s Fermi Gamma-ray Space Telescope reveals a feature never seen before.
The brightest gamma-ray burst yet recorded gave scientists a new high-energy feature to study. Learn what NASA’s Fermi mission saw, and what this feature may be telling us about the burst’s light-speed jets. Credit: NASA’s Goddard Space Flight Center
Download high-resolution video and images from NASA’s Scientific Visualization Studio
“A few minutes after the BOAT erupted, Fermi’s Gamma-ray Burst Monitor recorded an unusual energy peak that caught our attention,” said lead researcher Maria Edvige Ravasio at Radboud University in Nijmegen, Netherlands, and affiliated with Brera Observatory, part of INAF (the Italian National Institute of Astrophysics) in Merate, Italy. “When I first saw that signal, it gave me goosebumps. Our analysis since then shows it to be the first high-confidence emission line ever seen in 50 years of studying GRBs.”
A paper about the discovery appears in the July 26 edition of the journal Science.
When matter interacts with light, the energy can be absorbed and reemitted in characteristic ways. These interactions can brighten or dim particular colors (or energies), producing key features visible when the light is spread out, rainbow-like, in a spectrum. These features can reveal a wealth of information, such as the chemical elements involved in the interaction. At higher energies, spectral features can uncover specific particle processes, such as matter and antimatter annihilating to produce gamma rays.
“While some previous studies have reported possible evidence for absorption and emission features in other GRBs, subsequent scrutiny revealed that all of these could just be statistical fluctuations. What we see in the BOAT is different,” said coauthor Om Sharan Salafia at INAF-Brera Observatory in Milan, Italy. “We’ve determined that the odds this feature is just a noise fluctuation are less than one chance in half a billion.”
A jet of particles moving at nearly light speed emerges from a massive star in this artist’s concept. The star’s core ran out of fuel and collapsed into a black hole. Some of the matter swirling toward the black hole was redirected into dual jets firing in opposite directions. We see a gamma-ray burst when one of these jets happens to point directly at Earth. NASA’s Goddard Space Flight Center Conceptual Image Lab GRBs are the most powerful explosions in the cosmos and emit copious amounts of gamma rays, the highest-energy form of light. The most common type occurs when the core of a massive star exhausts its fuel, collapses, and forms a rapidly spinning black hole. Matter falling into the black hole powers oppositely directed particle jets that blast through the star’s outer layers at nearly the speed of light. We detect GRBs when one of these jets points almost directly toward Earth.
The BOAT, formally known as GRB 221009A, erupted Oct. 9, 2022, and promptly saturated most of the gamma-ray detectors in orbit, including those on Fermi. This prevented them from measuring the most intense part of the blast. Reconstructed observations, coupled with statistical arguments, suggest the BOAT, if part of the same population as previously detected GRBs, was likely the brightest burst to appear in Earth’s skies in 10,000 years.
The putative emission line appears almost 5 minutes after the burst was detected and well after it had dimmed enough to end saturation effects for Fermi. The line persisted for at least 40 seconds, and the emission reached a peak energy of about 12 MeV (million electron volts). For comparison, the energy of visible light ranges from 2 to 3 electron volts.
So what produced this spectral feature? The team thinks the most likely source is the annihilation of electrons and their antimatter counterparts, positrons.
“When an electron and a positron collide, they annihilate, producing a pair of gamma rays with an energy of 0.511 MeV,” said coauthor Gor Oganesyan at Gran Sasso Science Institute and Gran Sasso National Laboratory in L’Aquila, Italy. “Because we’re looking into the jet, where matter is moving at near light speed, this emission becomes greatly blueshifted and pushed toward much higher energies.”
If this interpretation is correct, to produce an emission line peaking at 12 MeV, the annihilating particles had to have been moving toward us at about 99.9% the speed of light.
“After decades of studying these incredible cosmic explosions, we still don’t understand the details of how these jets work,” noted Elizabeth Hays, the Fermi project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Finding clues like this remarkable emission line will help scientists investigate this extreme environment more deeply.”
The Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership managed by Goddard. Fermi was developed in collaboration with the U.S. Department of Energy, with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the United States.
By Francis Reddy
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Claire Andreoli
301-286-1940
claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Facebook logo @NASAUniverse @NASAUniverse Instagram logo @NASAUniverse Share
Details
Last Updated Jul 25, 2024 Related Terms
Black Holes Fermi Gamma-Ray Space Telescope Galaxies, Stars, & Black Holes Gamma Rays Gamma-Ray Bursts Goddard Space Flight Center Marshall Space Flight Center Stellar-mass Black Holes The Universe Keep Exploring Discover Related Topics
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
By NASA
The barred spiral galaxy NGC 6872 is interacting with a smaller galaxy to the upper left. The smaller galaxy has likely stripped gas from NGC 6872 to feed the supermassive black hole in its center.X-ray: NASA/CXC/SAO; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/J. Schmidt, L. Frattare, and J. Major To commemorate the 25th anniversary of NASA’s Chandra X-ray Observatory launch, the Chandra team released this never-seen-before image of NGC 6872, a spiral galaxy in the Pavo (Peacock) constellation, on July 22, 2024. This image and 24 others, which all include data from Chandra, demonstrate how X-ray astronomy explores all corners of the universe.
NGC 6872 is 522,000 light-years across, making it more than five times the size of the Milky Way galaxy; in 2013, astronomers from the United States, Chile, and Brazil found it to be the largest-known spiral galaxy, based on archival data from NASA’s Galaxy Evolution Explorer. This record was surpassed by NGC 262, a galaxy that measures 1.3 million light-years in diameter.
See more photos released for this celebration.
Image credit: X-ray: NASA/CXC/SAO; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/J. Schmidt, L. Frattare, and J. Major
View the full article
-
By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
These yellow crystals were revealed after NASA’s Curiosity happened to drive over a rock and crack it open on May 30. Using an instrument on the rover’s arm, scientists later determined these crystals are elemental sulfur — and it’s the first time this kind of sulfur has been found on the Red Planet.NASA/JPL-Caltech/MSSS NASA’s Curiosity captured this close-up image of a rock nicknamed “Snow Lake” on June 8, 2024, the 4,209th Martian day, or sol, of the mission. Nine days earlier, the rover had crushed a similar-looking rock and revealed crystalline textures — and elemental sulfur — inside.NASA/JPL-Caltech/MSSS Among several recent findings, the rover has found rocks made of pure sulfur — a first on the Red Planet.
Scientists were stunned on May 30 when a rock that NASA’s Curiosity Mars rover drove over cracked open to reveal something never seen before on the Red Planet: yellow sulfur crystals.
Since October 2023, the rover has been exploring a region of Mars rich with sulfates, a kind of salt that contains sulfur and forms as water evaporates. But where past detections have been of sulfur-based minerals — in other words, a mix of sulfur and other materials — the rock Curiosity recently cracked open is made of elemental, or pure, sulfur. It isn’t clear what relationship, if any, the elemental sulfur has to other sulfur-based minerals in the area.
While people associate sulfur with the odor from rotten eggs (the result of hydrogen sulfide gas), elemental sulfur is odorless. It forms in only a narrow range of conditions that scientists haven’t associated with the history of this location. And Curiosity found a lot of it — an entire field of bright rocks that look similar to the one the rover crushed.
Pan around this 360-degree video to explore Gediz Vallis channel, the location where NASA’s Curiosity Mars rover discovered sulfur crystals and drilled its 41st rock sample. The images that make up this mosaic were captured by the rover’s MastCam in June. Credit: NASA/JPL-Caltech/MSSS “Finding a field of stones made of pure sulfur is like finding an oasis in the desert,” said Curiosity’s project scientist, Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Southern California. “It shouldn’t be there, so now we have to explain it. Discovering strange and unexpected things is what makes planetary exploration so exciting.”
It’s one of several discoveries Curiosity has made while off-roading within Gediz Vallis channel, a groove that winds down part of the 3-mile-tall (5-kilometer-tall) Mount Sharp, the base of which the rover has been ascending since 2014. Each layer of the mountain represents a different period of Martian history. Curiosity’s mission is to study where and when the planet’s ancient terrain could have provided the nutrients needed for microbial life, if any ever formed on Mars.
NASA’s Curiosity Mars rover captured this view of Gediz Vallis channel on March 31. This area was likely formed by large floods of water and debris that piled jumbles of rocks into mounds within the channel.NASA/JPL-Caltech/MSSS Floods and Avalanches
Spotted from space years before Curiosity’s launch, Gediz Vallis channel is one of the primary reasons the science team wanted to visit this part of Mars. Scientists think that the channel was carved by flows of liquid water and debris that left a ridge of boulders and sediment extending 2 miles down the mountainside below the channel. The goal has been to develop a better understanding of how this landscape changed billions of years ago, and while recent clues have helped, there’s still much to learn from the dramatic landscape.
Since Curiosity’s arrival at the channel earlier this year, scientists have studied whether ancient floodwaters or landslides built up the large mounds of debris that rise up from the channel’s floor here. The latest clues from Curiosity suggest both played a role: some piles were likely left by violent flows of water and debris, while others appear to be the result of more local landslides.
While exploring Gediz Vallis channel in May, NASA’s Curiosity captured this image of rocks that show a pale color near their edges. These rings, also called halos, resemble markings seen on Earth when groundwater leaks into rocks along fractures, causing chemical reactions that change the color. NASA/JPL-Caltech/MSSS Those conclusions are based on rocks found in the debris mounds: Whereas stones carried by water flows become rounded like river rocks, some of the debris mounds are riddled with more angular rocks that may have been deposited by dry avalanches.
Finally, water soaked into all the material that settled here. Chemical reactions caused by the water bleached white “halo” shapes into some of the rocks. Erosion from wind and sand has revealed these halo shapes over time.
“This was not a quiet period on Mars,” said Becky Williams, a scientist with the Planetary Science Institute in Tucson, Arizona, and the deputy principal investigator of Curiosity’s Mast Camera, or Mastcam. “There was an exciting amount of activity here. We’re looking at multiple flows down the channel, including energetic floods and boulder-rich flows.”
A Hole in 41
All this evidence of water continues to tell a more complex story than the team’s early expectations, and they’ve been eager to take a rock sample from the channel in order to learn more. On June 18, they got their chance.
While the sulfur rocks were too small and brittle to be sampled with the drill, a large rock nicknamed “Mammoth Lakes” was spotted nearby. Rover engineers had to search for a part of the rock that would allow safe drilling and find a parking spot on the loose, sloping surface.
After Curiosity bored its 41st hole using the powerful drill at the end of the rover’s 7-foot (2-meter) robotic arm, the six-wheeled scientist trickled the powderized rock into instruments inside its belly for further analysis so that scientists can determine what materials the rock is made of.
Curiosity has since driven away from Mammoth Lakes and is now off to see what other surprises are waiting to be discovered within the channel.
More About the Mission
Curiosity was built by NASA’s Jet Propulsion Laboratory, which is managed by Caltech in Pasadena, California. JPL leads the mission on behalf of NASA’s Science Mission Directorate in Washington.
For more about Curiosity, visit:
science.nasa.gov/mission/msl-curiosity
News Media Contacts
Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433
andrew.c.good@jpl.nasa.gov
Karen Fox / Alana Johnson
NASA Headquarters, Washington
202-358-1600 / 202-358-1501
karen.c.fox@nasa.gov / alana.r.johnson@nasa.gov
2024-100
Share
Details
Last Updated Jul 18, 2024 Related Terms
Curiosity (Rover) Jet Propulsion Laboratory Mars Mars Science Laboratory (MSL) Explore More
6 min read Here’s How AI Is Changing NASA’s Mars Rover Science
Article 2 days ago 4 min read NASA’s Planetary Radar Tracks Two Large Asteroid Close Approaches
Article 2 weeks ago 3 min read NASA’s ECOSTRESS Maps Burn Risk Across Phoenix Streets
Article 2 weeks ago Keep Exploring Discover Related Topics
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
By NASA
5 Min Read NASA’s Hubble Traces Dark Matter in Dwarf Galaxy Using Stellar Motions
This NASA Hubble Space Telescope image reveals a section of the Draco dwarf galaxy. Credits:
NASA, ESA, Eduardo Vitral, Roeland van der Marel, and Sangmo Tony Sohn (STScI); Image processing: Joseph DePasquale (STScI) The qualities and behavior of dark matter, the invisible “glue” of the universe, continue to be shrouded in mystery. Though galaxies are mostly made of dark matter, understanding how it is distributed within a galaxy offers clues to what this substance is, and how it’s relevant to a galaxy’s evolution.
While computer simulations suggest dark matter should pile up in a galaxy’s center, called a density cusp, many previous telescopic observations have indicated that it is instead more evenly dispersed throughout a galaxy. The reason for this tension between model and observation continues to puzzle astronomers, reinforcing the mystery of dark matter.
A team of astronomers has turned toward NASA’s Hubble Space Telescope to try and clarify this debate by measuring the dynamic motions of stars within the Draco dwarf galaxy, a system located roughly 250,000 light-years from Earth. Using observations that spanned 18 years, they succeeded in building the most accurate three-dimensional understanding of stars’ movements within the diminutive galaxy. This required scouring nearly two decades of Hubble archival observations of the Draco galaxy.
A team of astronomers analyzed observations by NASA’s Hubble Space Telescope taken over a span of 18 years to measure the dynamic motions of stars within the Draco dwarf galaxy. The telescope’s extensive baseline and data archive enabled the team to build the most accurate three-dimensional map of the stars’ movements within the system. These improved measurements are helping to shed “light” on the mysterious qualities and behavior of dark matter, the universe’s invisible “glue.” The left image is from the Digitized Sky Survey (DSS). It presents a wider view of the region. The two right-side images are Hubble views. NASA, ESA, Eduardo Vitral, Roeland van der Marel, and Sangmo Tony Sohn (STScI), DSS; Image processing: Joseph DePasquale (STScI)
Download this image
“Our models tend to agree more with a cusp-like structure, which aligns with cosmological models,” said Eduardo Vitral of the Space Telescope Science Institute (STScI) in Baltimore and lead author of the study. “While we cannot definitively say all galaxies contain a cusp-like dark matter distribution, it’s exciting to have such well measured data that surpasses anything we’ve had before.”
Charting the Movements of Stars
To learn about dark matter within a galaxy, scientists can look to its stars and their movements that are dominated by the pull of dark matter. A common approach to measure the speed of objects moving in space is by the Doppler Effect – an observed change of the wavelength of light if a star is approaching or receding from Earth. Although this line-of-sight velocity can provide valuable insight, only so much can be gleaned from this one-dimensional source of information.
Besides moving closer or further away from us, stars also move across the sky, measured as their proper motion. By combining line-of-sight velocity with proper motions, the team created an unprecedented analysis of the stars’ 3D movements.
“Improvements in data and improvements in modeling usually go hand in hand,” explained Roeland van der Marel of STScI, a co-author of the paper who initiated the study more than 10 years ago. “If you don’t have very sophisticated data or only one-dimensional data, then relatively straightforward models can often fit. The more dimensions and complexity of data you gather, the more complex your models need to be to truly capture all the subtleties of the data.”
A Scientific Marathon (Not a Sprint)
Since dwarf galaxies are known to have a higher proportion of dark matter content than other types of galaxies, the team honed in on the Draco dwarf galaxy, which is a relatively small and spheroidal nearby satellite of the Milky Way galaxy.
“When measuring proper motions, you note the position of a star at one epoch and then many years later measure the position of that same star. You measure the displacement to determine how much it moved,” explained Sangmo Tony Sohn of STScI, another co-author of the paper and the principal investigator of the latest observational program. “For this kind of observation, the longer you wait, the better you can measure the stars shifting.”
The team analyzed a series of epochs spanning from 2004 to 2022, an extensive baseline that only Hubble could offer, due to the combination of its sharp stable vision and record time in operation. The telescope’s rich data archive helped decrease the level of uncertainty in the measurement of the stars’ proper motions. The precision is equivalent to measuring an annual shift a little less than the width of a golf ball as seen on the Moon from Earth.
With three dimensions of data, the team reduced the amount of assumptions applied in previous studies and considered characteristics specific to the galaxy – such as its rotation, and distribution of its stars and dark matter – in their own modeling efforts.
An Exciting Future
The methodologies and models developed for the Draco dwarf galaxy can be applied to other galaxies in the future. The team is already analyzing Hubble observations of the Sculptor dwarf galaxy and the Ursa Minor dwarf galaxy.
Studying dark matter requires observing different galactic environments, and also entails collaboration across different space telescope missions. For example, NASA’s upcoming Nancy Grace Roman Space Telescope will help reveal new details of dark matter’s properties among different galaxies thanks to its ability to survey large swaths of the sky.
“This kind of study is a long-term investment and requires a lot of patience,” reflected Vitral. “We’re able to do this science because of all the planning that was done throughout the years to actually gather these data. The insights we’ve collected are the result of a larger group of researchers that has been working on these things for many years.”
These results are accepted for publication in The Astrophysical Journal.
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 (STScI) in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Explore More
Hubble Space Telescope
Shining a Light on Dark Matter
Mystery of Galaxy’s Missing Dark Matter Deepens
Hubble Detects Smallest Known Dark Matter Clumps
Detailed Dark Matter Map Yields Clues to Galaxy Cluster Growth
Hubble Focus E-Book: Dark Universe
NASA’s Curious Universe Podcast: Welcome to the Dark Side
Dark Matter 101: Looking for the Missing Mass
All image products for this article
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contacts:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
Abigail Major and Ray Villard
Space Telescope Science Institute, Baltimore, MD
Science Contacts:
Eduardo Vitral, Roeland van der Marel, and Sangmo Tony Sohn
Space Telescope Science Institute, Baltimore, MD
Share
Details
Last Updated Jul 11, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Astrophysics Astrophysics Division Dark Matter Dark Matter & Dark Energy Goddard Space Flight Center Hubble Space Telescope Missions The Universe 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.
Shining a Light on Dark Matter
Dark Matter & Dark Energy
Roman
View the full article
-
By NASA
2 min read
Hubble Examines an Active Galaxy Near the Lion’s Heart
This NASA/ESA Hubble Space Telescope features the elliptical galaxy Messier 105. ESA/Hubble & NASA, C. Sarazin et al. It might appear featureless and unexciting at first glance, but NASA/ESA Hubble Space Telescope observations of this elliptical galaxy — known as Messier 105 — show that the stars near the galaxy’s center are moving very rapidly. Astronomers have concluded that these stars are zooming around a supermassive black hole with an estimated mass of 200 million Suns! This black hole releases huge amounts of energy as it consumes matter falling into it, making the system an active galactic nucleus that causes the galaxy’s center to shine far brighter than its surroundings.
Hubble also surprised astronomers by revealing a few young stars and clusters in Messier 105, a galaxy thought to be “dead” and incapable of star formation. Astronomers now think that Messier 105 forms roughly one Sun-like star every 10,000 years. Astronomers also spotted star-forming activity in a vast ring of hydrogen gas encircling both Messier 105 and its closest neighbor, the lenticular galaxy NGC 3384.
Discovered in 1781, Messier 105 lies about 30 million light-years away in the constellation of Leo (The Lion) and is the brightest elliptical galaxy within the Leo I galaxy group.
Text Credit: European Space Agency (ESA)
Download the image
Explore More
Hubble Space Telescope
Hubble’s Galaxies
Hubble’s Messier Catalog: Messier 105
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
Share
Details
Last Updated Jun 27, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Astrophysics Astrophysics Division Elliptical Galaxies Galaxies Galaxies, Stars, & Black Holes Goddard Space Flight Center Hubble Space Telescope Missions The Universe Keep Exploring Explore More With Hubble
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
What Did Hubble See on Your Birthday?
Name That Nebula
Hubble E-books
View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.