This image from NASA’s Mars Perseverance rover shows a potential megablock on the Jezero crater rim, taken by the Mastcam-Z instrument’s “right eye.” Mastcam-Z is a pair of cameras located high on the rover’s mast. Perseverance acquired this image looking east across the rim heading towards “Lac de Charmes” on Dec. 7, 2025 — Sol 1706, or Martian day 1,706 of the Mars 2020 mission — at the local mean solar time of 13:38:46.
NASA/JPL-Caltech/ASU
Written by Margaret Deahn, Ph.D. student at Purdue University
NASA’s Mars 2020 rover is currently trekking towards exciting new terrain. After roughly four months of climbing up and over the rim of Jezero crater, the rover is taking a charming tour of the plains just beyond the western crater rim, fittingly named “Lac de Charmes.” This area just beyond Jezero’s rim will be the prime place to search for pre-Jezero ancient bedrock and Jezero impactites — rocks produced or affected by the impact event that created Jezero crater.
The formation of a complex crater like Jezero is, well… complex. Scientists who study impact craters like to split the formation process into three stages: contact & compression (when the impactor hits), excavation (when materials are thrown out of the crater), and modification (when gravity causes everything to collapse). This process happens incredibly fast, fracturing the impacted rock and even melting some of the target material. Sometimes on Earth, the classic “bowl” shaped crater has been completely weathered and unrecognizable, so geologists are able to identify craters by the remnants of their impactites. Just when you thought it couldn’t get any more complicated — Jezero crater’s rim is located on the rim of another, even bigger basin called Isidis. That means there is an opportunity to have impactites from both cratering events exposed in and just around the rim — some of which could be several billions of years old! We may have already encountered one of these blocks on our trek towards Lac de Charmes. In the foreground of this image taken by the Mastcam-Z instrument on the rover, there is a potential impactite called a “megablock” that the team has named “Hyha.” We can actually see this block from orbit, it is that large! The team is excited to continue exploring these ancient rocks as we take our next steps off Jezero’s rim.
Want to read more posts from the Perseverance team?
NASA’s Perseverance Mars Rover Ready to Roll for Miles in Years Ahead
NASA’s Perseverance Mars rover captured this view of a location nicknamed “Mont Musard” on Sept. 8, 2025. Made up of three images, the panorama also captures another region, “Lac de Charmes,” where the rover’s team will be looking for more rock core samples to collect in the year ahead.
NASA/JPL-Caltech/ASU/MSSS
After nearly five years on Mars, NASA’s Perseverance rover has traveled almost 25 miles (40 kilometers), and the mission team has been busy testing the rover’s durability and gathering new science findings on the way to a new region nicknamed “Lac de Charmes,” where it will be searching for rocks to sample in the coming year.
Like its predecessor Curiosity, which has been exploring a different region of Mars since 2012, Perseverance was made for the long haul. NASA’s Jet Propulsion Laboratory in Southern California, which built Perseverance and leads the mission, has continued testing the rover’s parts here on Earth to make sure the six-wheeled scientist will be strong for years to come. This past summer, JPL certified that the rotary actuators that turn the rover’s wheels can perform optimally for at least another 37 miles (60 kilometers); comparable brake testing is underway as well.
Over the past two years, engineers have extensively evaluated nearly all the vehicle’s subsystems in this way, concluding that they can operate until at least 2031.
NASA’s Perseverance used its navigation cameras to capture its record-breaking drive of 1,350.7 feet (411.7 meters) on June 19, 2025. The navcam images were combined with rover data and placed into a 3D virtual environment, resulting in this reconstruction with virtual frames inserted about every 4 inches (0.1 meters) of drive progress. Credit: NASA/JPL-Caltech
“These tests show the rover is in excellent shape,” said Perseverance’s deputy project manager, Steve Lee of JPL, who presented the results on Wednesday at the American Geophysical Union’s annual meeting, the largest gathering of planetary scientists in the United States. “All the systems are fully capable of supporting a very long-term mission to extensively explore this fascinating region of Mars.”
Perseverance has been driving through Mars’ Jezero Crater, the site of an ancient lake and river system, where it has been collecting scientifically compelling rock core samples. In fact, in September, the team announced that a sample from a rock nicknamed “Cheyava Falls” contains a potential fingerprint of past microbial life.
More efficient roving
In addition to a hefty suite of six science instruments, Perseverance packs more autonomous capabilities than past rovers. A paper published recently in IEEE Transactions on Field Robotics highlights an autonomous planning tool called Enhanced Autonomous Navigation, or ENav. The software looks up to 50 feet (15 meters) ahead for potential hazards, then chooses a path without obstacles and tells Perseverance’s wheels how to steer there.
Engineers at JPL meticulously plan each day of the rover’s activities on Mars. But once the rover starts driving, it’s on its own and sometimes has to react to unexpected obstacles in the terrain. Past rovers could do this to some degree, but not if these obstacles were clustered near each other. They also couldn’t react as far in advance, resulting in the vehicles driving slower while approaching sand pits, rocks, and ledges. In contrast, ENav’s algorithm evaluates each rover wheel independently against the elevation of terrain, trade-offs between different routes, and “keep-in” or “keep-out” areas marked by human operators for the path ahead.
“More than 90% of Perseverance’s journey has relied on autonomous driving, making it possible to quickly collect a diverse range of samples,” said JPL autonomy researcher Hiro Ono, a paper lead author. “As humans go to the Moon and even Mars in the future, long-range autonomous driving will become more critical to exploring these worlds.”
New science
A paper published Wednesday in Science details what Perseverance discovered in the “Margin Unit,” a geologic area at the margin, or inner edge, of Jezero Crater. The rover collected three samples from that region. Scientists think these samples may be particularly useful for showing how ancient rocks from Mars’ deep interior interacted with water and the atmosphere, helping create conditions supportive for life.
From September 2023 to November 2024, Perseverance ascended 1,312 feet (400 meters) of the Margin Unit, studying rocks along the way — especially those containing the mineral olivine. Scientists use minerals as timekeepers because crystals within them can record details about the precise moment and conditions in which they formed.
Jezero Crater and the surrounding area holds large reserves of olivine, which forms at high temperatures, typically deep within a planet, and offers a snapshot of what was going on in the planet’s interior. Scientists think the Margin Unit’s olivine was made in an intrusion, a process where magma pushes into underground layers and cools into igneous rock. In this case, erosion later exposed that rock to the surface, where it could interact with water from the crater’s ancient lake and carbon dioxide, which was abundant in the planet’s early atmosphere.
Those interactions form new minerals called carbonates, which can preserve signs of past life, along with clues as to how Mars’ atmosphere changed over time.
“This combination of olivine and carbonate was a major factor in the choice to land at Jezero Crater,” said the new paper’s lead author, Perseverance science team member Ken Williford of Blue Marble Space Institute of Science in Seattle. “These minerals are powerful recorders of planetary evolution and the potential for life.”
Together, the olivine and carbonates record the interplay between rock, water, and atmosphere inside the crater, including how each changed over time. The Margin Unit’s olivine appeared to have been altered by water at the base of the unit, where it would have been submerged. But the higher Perseverance went, the more the olivine bore textures associated with magma chambers, like crystallization, and fewer signs of water alteration.
As Perseverance leaves the Margin Unit behind for Lac de Charmes, the team will have the chance to collect new olivine-rich samples and compare the differences between the two areas.
More about Perseverance
Managed for NASA by Caltech, NASA’s Jet Propulsion Laboratory in Southern California built and manages operations of the Perseverance rover on behalf of the agency’s Science Mission Directorate as part of NASA’s Mars Exploration Program portfolio.
The future of flight, space exploration, and science starts at NASA’s Langley Research Center in Hampton, Virginia, where we have been advancing innovation for more than 100 years. Join us as we look back at NASA Langley’s achievements in 2025 that continued our storied legacy of pushing the boundaries of what is possible.
Langley Researchers Explore MARVL-ous Technology for Future Trips to Mars
Modular Assembled Radiators for Nuclear Electric Propulsion Vehicles, or MARVL, aims to take a critical element of nuclear electric propulsion, its heat dissipation system, and divide it into smaller components that can be assembled robotically and autonomously in space. This is an artist’s rendering of what the fully assembled system might look like.
NASA
As NASA returns astronauts to the Moon through the agency’s Artemis campaign in advance of human exploration of Mars, researchers at Langley are exploring technology that could significantly reduce travel time to the Red Planet. Modular Assembled Radiators for Nuclear Electric Propulsion Vehicles, or MARVL, would use robots for in-space assembly of elements needed to enable nuclear electric propulsion of future spacecraft, which could transform travel to deep space.
NASA Cameras Catch First-of-its-Kind Moon Close-up
This rendering demonstrates what is happening during a stellar occultation and illustrates an example of the light curve data graph recorded by scientists that enables them to gather atmospheric measurements, like temperature and pressure, from Uranus as the amount of starlight changes when the planet eclipses the star.
NASA/Langley Research Center Advanced Concepts Laboratory
In April, planetary scientists at Langley led an international team of astronomers during a cosmic alignment three decades in the making: a rare opportunity to study Uranus. The one-hour event gave them a glimpse into the planet’s atmosphere, information that could enable future Uranus exploration efforts.
NASA Instrument Measures Wind for Improved Weather Forecasts
This visualization shows AWP 3D measurements gathered on Oct. 15, 2024, as NASA’s G-III aircraft flew along the East Coast of the U.S. and across the Great Lakes region. Laser light that returns to AWP as backscatter from aerosol particles and clouds allows for measurement of wind direction, speed, and aerosol concentration as seen in the separation of data layers.
NASA Scientific Visualization Studio
Severe or extreme weather can strike in a moment’s notice, and having the tools to accurately predict weather events can help save lives and property. Scientists at Langley have developed and are testing an instrument that uses laser technology to gather precise wind measurements, data that is a crucial element for accurate weather forecasting.
Langley Researchers Develop New Technique to Test Long, Flexible Booms
Researchers look at a bend that occurred in the 94-foot triangular, rollable and collapsible boom during an off-axis compression test.
NASA/David C. Bowman
Gravity can create issues when testing materials for space, but Langley researchers have found a way to successfully use gravity and height when testing long composite booms. Testing these composite booms is important because they could support space exploration in a variety of ways, including being used to build structures that could support humans living and working on the Moon.
NASA Imaging Team Supports Missions to Advance Space Exploration, Science
A rendering of a space capsule from The Exploration Company re-entering Earth’s atmosphere.
Image courtesy of The Exploration Company
A Langley team that specializes in capturing imagery-based engineering datasets from spacecraft during launch and reentry continued its work in 2025, including support of a European aerospace company’s test flight in June. Not only does the team support a variety of missions to advance the agency’s work, but they also collaborate with the private sector as NASA works to open space to more science, people, and opportunities.
NASA Instrument Uses Moonlight for Improved Space Measurements
An artist’s rendering of NASA’s Arcstone instrument on-orbit gathering measurements of lunar reflectance.
Blue Canyon Technologies
One of the most challenging tasks in remote sensing from space is achieving required instrument calibration on-orbit. Langley scientists are addressing the challenge head on through the Arcstone mission, an instrument that launched in June and aims to establish the Moon as a cost-efficient, high-accuracy calibration reference. Once established, the new standard can be applied to past, present, and future spaceborne sensors and satellite constellations. Arcstone uses a spectrometer, a scientific instrument that measures and analyzes light, to measure lunar spectral reflectance.
NASA Mission Continues Monitoring Air We Breathe
By measuring nitrogen dioxide (NO2) and formaldehyde (HCHO), TEMPO can derive the presence of near-surface ozone. On Aug. 2, 2024 over Houston, TEMPO observed exceptionally high ozone levels in the area. On the left, NO2 builds up in the atmosphere over the city and over the Houston Ship Channel. On the right, formaldehyde levels are seen reaching a peak in the early afternoon. Formaldehyde is largely formed through the oxidation of hydrocarbons, an ingredient of ozone production, such as those that can be emitted by petrochemical facilities found in the Houston Ship Channel.
NASA’s Scientific Visualization Studio
The success of NASA’s Tropospheric Emissions: Monitoring of Pollution mission, or TEMPO, earned the mission an extension, meaning the work to monitor Earth’s air quality from 22,000 miles above the ground will continue through at least September 2026. The Langley-led mission launched in 2023 and is NASA’s first to use a spectrometer, a scientific instrument that measures and analyzes light, to gather hourly air quality data continuously over North America during daytime hours. The data gathered is distributed freely to the public, giving air quality forecasters, scientists, researchers, and your next-door neighbor access to quality information about the air we breathe down to the neighborhood level.
NASA Tests New, Innovative Tech to Enable Faster Launches at Lower Costs
The fully assembled and tested Athena EPIC satellite which incorporates eight HISats mounted on a mock-up of a SpaceX provided launch pedestal which will hold Athena during launch.
NovaWurks
NASA’s Athena Economical Payload Integration Cost mission, or Athena EPIC, launched in July with the goal to shape a future path to launch that saves taxpayers money and expedites access to space. Athena EPIC was the first NASA-led mission led to utilize HISat technology, small satellites engineered to aggregate, share resources, and conform to different sizes and shapes. Langley’s scientists designed and built the Athena sensor with spare parts from NASA’s CERES (Clouds and the Earth’s Radiant Energy System) mission to gather top of atmosphere measurements. Athena EPIC demonstrates a novel way to launch Earth-observing instruments into orbit quicker and more economically.
Drop Test at Langley Offers Research, Data for Potential Air Taxi Designs
The future of air travel includes the safe integration of drones and air taxis into our airspace for passenger transport, cargo delivery, and public service capabilities.That is why NASA is investigating and testing potential air taxi materials and designs to help the aviation industry better understand how those materials behave under impact. Data collected from a drop test at Langley’s Landing and Impact Research Facility in June will help in the development of safety regulations for advanced air mobility aircraft, leading to safer designs.
Langley Wind Tunnel Tests Help Support Advanced Air Mobility Aircraft Development
NASA researcher Norman W. Schaeffler adjusts a propellor, which is part of a 7-foot wing model that was recently tested at NASA’s Langley Research Center in Hampton, Virginia. In May and June, NASA researchers tested the wing in the 14-by-22-Foot Subsonic Wind Tunnel to collect data on critical propeller-wing interactions. The lessons learned will be shared with the public to support advanced air mobility aircraft development.
NASA/Mark Knopp
NASA advanced the future of air taxis and autonomous cargo drones by testing a 7-foot wing model in Langley’s 14-by-22-Foot Subsonic Wind Tunnel. This effort produced data on critical propeller-wing interactions, as well as data relevant to cruise, hover, and transition conditions for advanced air mobility aircraft. The results will help validate next-generation design tools and accelerate safe, reliable development across the advanced air mobility industry.
NASA Tests Air Taxi Tech for Future Aircraft Development
The Research Aircraft for electric Vertical takeoff and landing Enabling techNologies Subscale Wind Tunnel and Flight Test undergoes a free flight test on the City Environment Range Testing for Autonomous Integrated Navigation range at NASA’s Langley Research Center in Hampton, Virginia on April 22, 2025.
NASA/Rob Lorkiewicz
The lack of publicly available engineering and flight data to help address technical barriers in the design and development of new electric vertical takeoff and landing (eVTOL) aircraft is a challenge for researchers and engineers. That is why Langley researchers are using a research aircraft that provides real-world data, obtained through wind tunnel and flight tests, to help fill the information gap and check the accuracy of computer models for flight dynamics and controls. Making this data available to all is a key step in transforming the way we fly and safely integrating new aircraft into our nation’s airspace.
NASA Material Flies High for Study of Long-Term Effects of Space
Robert Mosher, HIAD materials and processing lead at NASA Langley, holds up a piece of f webbing material, known as Zylon, which comprise the straps of the HIAD.
NASA/Joe Atkinson
A material from NASA Langley is riding high as it orbits the Earth aboard a United States Space Force test vehicle, giving researchers a better understanding of how the material responds to long-duration exposure to the harsh vacuum of space. The strap material is a part of a Langley-developed aeroshell to protect spacecraft re-entering Earth’s atmosphere or to ensure their safe landing on other celestial bodies, such as Mars. Understanding how extended exposure to space affects the material is important as NASA prepares to send humans beyond the Moon.
NASA Flights Study Impacts of Space Weather on Travelers
Frozen and rocky terrain in the Polar region observed from above Nuuk, Greenland during NASA’s SWXRAD science flights.
NASA/Guillaume Gronoff
Data gathered during a Langley-led airborne science campaign late this summer could help protect air travelers on Earth and future space travelers to the Moon, Mars, and beyond from the health risks associated with radiation exposure. NASA’s Space Weather Aviation Radiation (SWXRAD) aircraft flight campaign took place in Greenland and measured the radiation dose level to air travelers from cosmic radiation. Researchers are using the information to enhance a modeling system that offers real-time global maps of the hazardous radiation in the atmosphere and creates exposure predictions for aircraft and spacecraft.
NASA’s Dragonfly Completes Wind Tunnel Tests at Langley
Set up and testing of Dragonfly model in the Transonic Dynamics Tunnel
NASA/David C. Bowman
As NASA returns astronauts to the Moon through the Artemis campaign in preparation for human exploration of Mars, the agency also has its sights set on Saturn, specifically Saturn’s moon Titan. NASA’s Dragonfly, a car-sized rotorcraft set to launch no earlier than 2028, will explore Titan and try to discover how life began. This fall, engineers placed a full-scale test model representing half of the Dragonfly lander in Langley’s Transonic Dynamics Tunnel to evaluate how its rotor system performed in Titan-like conditions. The data will be integral in developing the rotorcraft’s flight plans and navigation software as it investigates multiple landing sites on Titan.
NASA Offers Science, Technology, and Expertise During Disaster Response
True color imagery of Hurricane Milton on Oct. 7, 2024, from the NOAA-21 satellite.
NASA / NOAA
In response to severe weather that impacted more than 10 states in November, the NASA Disasters Response Coordination System (DRCS) activated to support national partners. The DRCS is headquartered at Langley. NASA worked closely with the National Weather Service and the Federal Emergency Management Agency serving the central and southeastern U.S. to provide satellite data and expertise that help communities better prepare, respond, and recover.
NASA’s X-59 Takes Flight
In October, NASA’s Quesst mission celebrated a major milestone – the X-59 quiet supersonic one-of-a-kind research aircraft flew for the first time, a historic moment for aviation. The hard work, talent, and innovation of NASA engineers and project team members, including many based at NASA Langley, made this achievement possible. One of the notable traits of the X-59 is the eXternal Vision System (XVS) which allows the test pilots to safely maneuver the skies without a forward-facing window. This unique supersonic design feature was developed and tested at NASA Langley.
The X-59’s first flight was a major step toward quiet supersonic flight over land, which could revolutionize air travel.
What a Blast! Langley Begins Plume-Surface Interaction Tests
Views of the 60-foot vacuum sphere in the which the plume-surface interaction testing is happening.
NASA/Joe Atkinson
A team at NASA Langley is firing engine plumes into simulated lunar soil because as the United States returns to the Moon, both through NASA’s Artemis campaign and the commercialization of space, researchers need to understand the hazards that may occur when a lander’s engines blast away at the lunar dust, soil, and rocks.
Langley Inspires Through Community Engagement, Educational Opportunities
NASA Langley highlights its Cirrus Design SR22 during Air Power Over Hampton Roads STEM Day.
NASA/Angelique Herring
Langley connected with communities across Virginia and beyond to share the center’s work and impact, and inspire the next generation of explorers, scientists, and researchers. Thousands of spectators enjoyed hands-on activities and exhibits during the Air Power over Hampton Roads air show at Joint Base Langley-Eustis in Hampton, Virginia, where NASA Langley’s aviation past, present, and future were on full display. More than 2,300 students from across the nation eagerly participated in Langley’s 2025 Student Art Contest, and shared their artistic spin on the theme, “Our Wonder Changes the World.” Langley and Embry-Riddle Aeronautical University announced an agreement in September that will leverage Langley’s aerospace expertise and Embry-Riddle’s specialized educational programs and research to drive innovation in aerospace, research, education, and technology, while simultaneously developing a highly skilled workforce for the future of space exploration and advanced air mobility.
Langley looks forward to another year of successes and advancements in 2026, as we continue to make the seemingly impossible, possible.
Icons of winter are sometimes found in unexpected places. In one striking example, a series of oval lagoons in a remote part of Siberia forms the shape of a towering snowman when viewed from above.
This image, centered on the remote village of Billings and nearby Cape Billings on Russia’s Chukchi Peninsula, was captured by the OLI (Operational Land Imager) aboard Landsat 8 on June 16, 2025. Established in the 1930s as a port and supply point for the Soviet Union, the village sits on a narrow sandspit that separates the Arctic Ocean from a series of connected coastal inshore lagoons.
The elongated, oval lagoons are frozen over and flanked by sea ice. Though June is one of the warmest months in Billings, ice cover is routine even then. Mean daily minimum temperatures are just minus 0.6 degrees Celsius (30.9 degrees Fahrenheit) in June, according to meteorological data.
Though the shape may seem engineered, it is natural and the product of geological processes common in the far north. The ground in this part of Siberia is frozen most of the year and pockmarked with spear-shaped ice wedges buried under the surface. Summer melting causes overlying soil to slump, leaving shallow depressions that fill with meltwater and form thermokarst lakes. Once created, consistency in the direction of the winds and waves likely aligned and elongated the lakes into the shapes seen in the image. The thin ridges separating the lakes may represent the edges of different ice wedges below the surface.
The first reference to humans building snowmen dates back to the Middle Ages, according to the book The History of the Snowman. While three spherical segments are the most common form, other variants dominate in certain areas. In Japan, snowmen typically have just two segments and are rarely given arms. This five-segmented snowman-shaped series of lakes spans about 22 kilometers (14 miles) from top to bottom, making it roughly 600 times longer than the actual snowwoman that held the Guinness record for being the world’s tallest snowperson in 2025.
Snowmen are not the only winter icons tied to this remote landscape. For early expeditions to the Russian Arctic, reindeer offered one of the most reliable modes of transportation. That includes expeditions by the town’s namesake, Commodore Joseph Billings, a British-born naval officer who enlisted in the Russian navy and led a surveying expedition to find a Northeast Passage between 1790 and 1794.
Although the hundred-plus members of the expedition did not reach Cape Billings, they explored much of the Chukchi Peninsula, producing some of the first accurate maps and further confirming that Asia and North America were separated by a strait. In the winter months, when their ships were beset by ice, the explorers moved to temporary camps on land and instead surveyed the region with reindeer-drawn wooden sleds, according to historical accounts. Winters, in fact, offered the best conditions for exploration because the peninsula’s many rivers and lakes turned into solid surfaces that were easy to traverse in comparison to the muddy bogs that open up in the summer.
Indigenous Chukchi people living on the peninsula at the time routinely used reindeer to haul both people and cargo. A pair of reindeer can comfortably haul hundreds of pounds for several hours a day. In addition to their impressive endurance in cold temperatures, reindeer largely feed themselves by digging through snow and grazing on lichens, something that neither sled dogs nor horses can do.
Historical documents indicate that the Billings expedition enlisted Chukchi people to manage and care for the reindeer they used, with some accounts suggesting that the explorers used dozens of reindeer at times. While reindeer were mainly used to haul sleds, Chukchi people likely rode them as well.
Non-Chukchi members of the expedition reportedly experimented with riding reindeer, though their experiments did not always go smoothly. Billings’ secretary and translator Martin Sauer reported using a saddle without stirrups or a bridle and falling “nearly 20 times” after about three hours of travel in his account of the expedition. Not only that, he added, but the saddle “at first, causes astonishing pain to the thighs.”
NASA Earth Observatory image by Michala Garrison, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.
References & Resources
Alekseev, A.I. (1966) Joseph Billings. The Geographical Journal, 132(2), 233-238.
Arctic Portal Chukchi. Accessed December 16, 2025.
NASA IXPE’s Longest Observation Solves Black Hole Jets Mystery
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Two composite images show side-by-side observations of the Perseus Cluster from NASA’s IXPE (Imaging X-Ray Polarimetry Explorer) and Chandra X-ray Observatory. Scientists used data from both observatories, along with data from Nuclear Spectroscopic Telescope Array (NuSTAR), and Neil Gehrels Swift Observatory, to confirm measurements of the galaxy cluster.
X-ray: (Chandra) NASA/CXC/SAO, (IXPE) NASA/MSFC; Image Processing: NASA/CXC/SAO/N. Wolk and K. Arcand
Written by Michael Allen
An international team of astronomers using NASA’s IXPE (Imaging X-ray Polarimetry Explorer) has identified the origin of X-rays in a supermassive black hole’s jet, answering a question that has been unresolved since the earliest days of X-ray astronomy. Their findings are described in a paper published in The Astrophysical Journal Letters, by the American Astronomical Society, Nov. 11.
The IXPE mission observed the Perseus Cluster, the brightest galaxy cluster i observable in X-rays, for more than 600 hours over a 60-day period between January and March. Not only is this IXPE’s longest observation of a single target to date, it also marks IXPE’s first time observing a galaxy cluster.
Specifically, the team of scientists studied the polarization properties of 3C 84, the massive active galaxy located at the very center of the Perseus Cluster. This active galaxy is a well-known X-ray source and a common target for X-ray astronomers because of its proximity and brightness.
Because the Perseus Cluster is so massive, it hosts an enormous reservoir of X-ray emitting gas as hot as the core of the Sun. The use of multiple X-ray telescopes, particularly the high-resolution imaging power of NASA’s Chandra X-ray Observatory was essential to disentangle the signals in the IXPE data. Scientists combined these X-ray measurements with data from the agency’s Nuclear Spectroscopic Telescope Array (NuSTAR) mission and Neil Gehrels Swift Observatory.
Fast facts
Polarization measurements from IXPE carry information about the orientation and alignment of emitted X-ray light waves. The more X-ray waves traveling in sync, the higher the degree of polarization.
X-rays from an active galaxy like 3C 84 are thought to originate from a process known as inverse Compton scattering, where light bounces off particles and gains energy. The polarization measurements from IXPE allow us to identify the presence of either inverse Compton scattering or other scenarios.
“Seed photons” is the term for the lower-energy radiation undergoing the energizing process of inverse Compton scattering.
“While measuring the polarization of 3C 84 was one of the key science goals, we are still searching for additional polarization signals in this galaxy cluster that could be signatures of more exotic physics,” said Steven Ehlert, project scientist for IXPE and astronomer at NASA’s Marshall Space Flight Center in Huntsville.
Chandra & IXPE composite image of the Perseus Cluster.
X-ray: (Chandra) NASA/CXC/SAO, (IXPE) NASA/MSFC; Image Processing: NASA/CXC/SAO/N. Wolk and K. Arcand
“We’ve already determined that for sources like 3C 84, the X-rays originated from inverse Compton scattering,” said Ioannis Liodakis, a researcher at the Institute of Astrophysics – FORTH in Heraklion, Greece, and lead author on the paper. “With IXPE observations of 3C 84 we had a unique chance to determine the properties of the seed photons.”
The first possible origin scenario for the seed photons is known as synchrotron self-Compton, where lower-energy radiation originates from the same jet that produces the highly energetic particles.
In the alternative scenario known as external Compton, seed photons originate from background radiation sources unrelated to the jet.
“The synchrotron self-Compton and external Compton scenarios have very different predictions for their X-ray polarization,” said Frederic Marin, an astrophysicist at the Strasbourg Astronomical Observatory in France and co-author of the study. “Any detection of X-ray polarization from 3C 84 almost decisively rules out the possibility of external Compton as the emission mechanism.”
Throughout the 60-day observation campaign, optical and radio telescopes around the world turned their attention to 3C 84 to further test between the two scenarios.
NASA’s IXPE measured a net polarization of 4% in the X-rays spectrum, with comparable values measured in the optical and radio data. These results strongly favor the synchrotron self-Compton model for the seed photons, where they come from the same jet as the higher-energy particles.
“Separating these two components was essential to this measurement and could not be done by any single X-ray telescope, but by combining the IXPE polarization data with Chandra, NuSTAR, and Swift, we were able to confirm this polarization measurement was associated specifically with 3C 84,” said Sudip Chakraborty, a researcher at the Science and Technology Institute of the Universities Space Research Association in Huntsville, Alabama, and co-author on the paper.
Scientists will continue to analyze IXPE’s data from different locations in the Perseus Cluster for different signals.
More about IXPE
NASA’s IXPE, which continues to provide unprecedented data enabling groundbreaking discoveries about celestial objects across the universe, is a joint NASA and Italian Space Agency mission with partners and science collaborators in 12 countries. The IXPE mission is led by NASA’s Marshall Space Flight Center in Huntsville, Alabama. BAE Systems, Inc., headquartered in Falls Church, Virginia, manages spacecraft operations together with the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder.
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