Passion and Precision: Meet IXPE Italian ‘Primo Tecnologo’ Elisabetta Cavazzuti

By Rick Smith

Italian astrophysicist Elisabetta Cavazzuti spends her spare time rappelling down steep cliffs and waterfalls. This sport, called “canyoning,” combines a sharp respect for physics and precision engineering with a deep love for the beauty of nature.

The rest of the time, her focus is on the stars, which demand the same precise, passionate mix.

Since 2018, Cavazzuti has served as the Italian Space Agency’s “Primo Tecnologo” – or program manager-cum-chief technologist – for IXPE (Imaging X-ray Polarimetry Explorer). In that role, she’s the coordinator for all technical and management activities for the first X-ray polarimetry mission ever flown – and she’s proud of the unprecedented nature of the work.

A woman with short brown hair talks on the phone in an office with images from IXPE behind her.
Elisabetta Cavazzuti, the Italian IXPE program manager, coordinates all IXPE technical and management activities for the Italian Space Agency, which partners with NASA on the X-ray polarimetry mission and its results. (Photo courtesy of Elisabetta Cavazzuti)

“IXPE is such a new science that when we go to conferences to present results, we still get comparatively few questions,” she said. “People are just beginning to understand the scale of the new window X-ray polarimetry has opened for us. We’re helping X-ray astronomers and researchers expand their knowledge. This work is special.”

Cavazzuti, who has spent much of her career specializing in gamma ray and X-ray studies, earned a degree in astrophysics in 1995 at the University of Bologna and a doctorate in astronomy in 2006 at the Sapienza University of Rome.

While completing her doctoral studies, she joined the aerospace industry, initially helping to develop and test the soft gamma-ray detector on the European Space Agency’s INTEGRAL (International Gamma-Ray Astrophysics Laboratory) satellite. Cavazzuti was tasked with assembling INTEGRAL’s soft gamma-ray detector, a compact piece of hardware covered in 4,096 scintillator crystals, which turn light into electrical current.

“I spent four years in a clean room, testing different glues to couple the elements, testing filters to wrap each individual scintillator, testing the detector itself,” she said. “It was pure experimental physics, and it helped shape my career.”

From there, she joined the Italian Space Agency in 2001, immersing herself in X-ray and gamma-ray studies of extragalactic sources including blazars and contributing to other Italian and joint international space science missions.

Cavazzuti joined the FERMI mission team in 2006, leading construction of the gamma-ray imager and later serving as co-leader of FERMI science working groups dedicated to studies of active galactic nuclei and blazars and to cataloguing sources observed by the telescope. In time, she was asked to serve as coordinator for the global FERMI collaboration. She accepted the one-year post, and spent 2017 at NASA’s Goddard Space Flight Center, overseeing all eight FERMI science working groups.

Since then, she has returned to her dual science-and-technology leadership role, continuing her own gamma-ray research while also guiding new flight missions and science instruments, including IXPE, from drawing board to post-launch data analysis. She liaises with academic partners at Italy’s National Institute of Astrophysics and National Institute for Nuclear Physics and with industry worldwide. In 2015, she led the Italian Space Agency’s development and delivery of the Italian contribution to the Japanese-led CALET (CALorimetric Electron Telescope), which aids studies of cosmic rays and dark matter on the International Space Station.

The lure of space science first drew Cavazzuti as a high school astronomy student. Her talent for program management isn’t built on the same fundamental passion, she said – but what keeps her engaged is the people.

“In our program, management permits me to focus on the team,” she said. “Of course we work to ensure projects are on schedule and on cost, but all of it hinges on oversight of people: engineers, scientists, professors, contractors. Every time we assemble a team, there are new ideas and insights, new group dynamics. That’s the element I like most.”

A woman in rock climbing gear is seen climbing up a rock.
In her spare time, Elisabetta Cavazzuti, seen here among fellow fans of the outdoors, enjoys climbing steep cliffs, waterfalls, and other dizzying heights. (Photo courtesy of Elisabetta Cavazzuti)

Cavazzuti – who enjoys hiking, skiing, and caving as well as canyoning – said she’s reluctant to give up either of the hats she now wears, despite her very busy schedule. Both, she said, are vital to succeed.

“I work to keep my research alive, because that intensive scientific investigation keeps me engaged,” she said. “And managing programs helps me understand and guide what the instruments can do when they fly. With each new mission, I learn a new piece of technology and a new aspect of science.”

As work on IXPE continues, Cavazzuti is already taking on new endeavors. First up is the planned European Space Agency satellite ATHENA (Advanced Telescope for High Energy Astrophysics), a large X-ray observatory launching in 2037 to detect the formation and evolution of the highest-energy sources in the cosmos: black holes, gamma ray bursts, even the plasma contained in dark matter.

Solid time management makes it all possible, she said, but curiosity – the unflagging desire to observe, to seek, to explore – is the most critical factor.

“People often fear they lack the brainpower to embrace science and technology. They ask themselves, ‘Am I intelligent enough to understand this work?’ Yes! We all are! I’m not an expert on many things; I change focus too often to become an expert in some areas of study,” Cavazzuti said.

“But I am curious, and I am surrounded by curious people,” she added, “and together we walk the same path.”

Learn more about IXPE and its international partnership here.

Irresistible Gravity: Meet IXPE General Observer Program Lead Kavitha Arur

By Rick Smith

A black hole is a region of spacetime where gravity is so relentless that nothing nearby – not stars, not even light – can resist its pull.

Astrophysicist Kavitha Arur can’t resist it either. She’s been fascinated with black holes since childhood.

Kavitha Arur sits at her desk and works on the computer in her office.
Kavitha Arur, IXPE General Observer Program lead at NASA’s Goddard Space Flight Center, ponders new science proposals using the powerful X-ray imager. The window for proposals from the science community closes Oct. 18. (Photo: NASA)

“I always enjoyed mysteries and solving puzzles, and astronomy is full of them,” said Arur, a post-doctoral researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “By ninth grade, all I wanted to study was black holes – the most extreme objects in the known universe, puzzles just waiting to be solved.”

Today, Arur leads the Imaging X-ray Polarimetry Explorer (IXPE) General Observer Program, which invites astrophysicists and other space scientists around the world to propose and take part in studies using the IXPE telescope. The program enables scientists to propose targets of study across the cosmos: black holes, neutron stars, active galactic nuclei, supernova remnants, and other high-energy X-ray sources.

Launched in late 2021, IXPE’s science activities so far have been directed by researchers at NASA and the Italian Space Agency, in conjunction with a science advisory team including more than 175 researchers from 13 countries.

When the General Observer Program commences in February 2024, as much as 80% of IXPE’s time will be made available to the broader scientific community.

“We’re excited to expand IXPE’s reach and usefulness,” Arur said. “We want to maximize science outputs as widely as possible and cover the widest possible range of targets.”

Born and raised in Chennai, India, Arur filled her high school schedule with as much general science and mathematics as possible and, upon graduation, resolved to pursue her passion wherever it led. She earned her integrated bachelor’s and master’s degree in physics and astronomy at the University of Southampton in the United Kingdom in 2013, a Master of Science in physics at Texas Tech University in Lubbock in 2015, and a doctorate in physics at Texas Tech in 2020.

Her research primarily focuses on X-ray binaries, wherein a black hole or neutron star strips a nearby companion star of material. Arur applies a fairly new analysis technique called the bispectrum – developed to study ocean waves and used to assess how brainwaves change under anesthesia – to study quasi-periodic oscillations from these X-ray binary systems. Her work is helping to decipher the geometry of regions close to the black hole, enabling researchers to create better geometric models to explain the complex timing behavior of these objects.

IXPE, which measures X-ray polarization – the average direction and intensity of the electric field of light waves – offers a similarly unique and unprecedented research opportunity, she said. And under her leadership, the General Observer Program will take full advantage of it.

“We’re working closely with IXPE mission leads at NASA’s Marshall Space Flight Center to determine how best to serve and benefit the entire research community,” she said. “We’ve also enlisted the help of NASA information technologists and data archive managers to ensure a smooth transition from the prime mission to the general observer program. Our chief goal to enable every interested party to use, analyze, and interpret IXPE data.”

The call for IXPE General Observer Program study proposals can be found here. The window for proposals closes Oct. 18.

Jonathan Deal
NASA’s Marshall Space Flight Center

Taking Full Measure of the Sky: Meet IXPE’s Italian Co-principal Investigator Luca Baldini

By Rick Smith

When Italian researcher Luca Baldini stepped down as analysis coordinator for NASA’s Fermi Gamma Ray Space Telescope in 2016 to help develop IXPE, the Imaging X-ray Polarimetry Explorer, colleagues presented him with a flamethrowing guitar. It was a spot-on gift for a musician and scientist who, in his spare time, crafts his own guitars and other stringed instruments.

Not that Baldini, the Italian co-principal investigator for IXPE, has a lot of time to spare nowadays. The IXPE mission represents the culmination of X-ray polarimetry gas pixel detector research and development he has helped to pioneer since 2001.

A photo of a white man in a black polo shirt.
Luca Baldini, IXPE Italian co-principal investigator. (Image courtesy of Luca Baldini)

“I’m an experimentalist, not an astronomer,” said Baldini, an associate professor of physics at the University of Pisa in Italy and a researcher at the National Institute of Nuclear Physics in Rome. “My passion is hardware and software development, so I tend to find the study of extended X-ray sources the most challenging: supernova remnants such as Tycho and Cassiopeia A, the Crab Nebula, even the galactic center.

“From the standpoint of analysis, these are the most interesting targets of study to me, because we’re using IXPE’s detector to its full potential, taking full measure of the sky to infer the properties and physics of each source,” he added.

On IXPE, Baldini was a key developer of the imager’s sophisticated detector and data acquisition system, event reconstruction software, and “Monte Carlo” simulator.

Named for the French city, a Monte Carlo simulator generates random numbers for modeling stochastic events in space – those possessing a wildly unpredictable pattern of behavior that can be analyzed statistically but never precisely forecasted, much like dice thrown or roulette wheels spun in the city famous for its casinos. And they’re critical to an astrophysics mission before the payload ever leaves the ground.

“Monte Carlo simulations are very important in the initial design of any experiment – how sensitive the detector should be, how large its field of view, what types of readouts are sought,” Baldini said. “You run the sims, optimize the detector’s requirements, and build the best hardware possible. As new data is fed into the simulator from the instrument in flight, the resulting models get better and better.”

Since 2002, Baldini also has been an integral part of the team responsible for the Large Area Telescope, the principal science instrument on NASA’s Fermi Telescope, which was launched to space in 2008 to study high-energy gamma ray emitters: pulsars, binary stars, supernova remnants, active galactic nuclei and more.

He contributed to the telescope’s development and operation, including construction of its sophisticated silicon tracker, ongoing monitoring of the instrument’s performance in orbit, and scientific analysis of the data it gathers, pursuing answers to key questions about physics, high-energy cosmic rays, and dark matter.

Baldini and the Italian team assembled the Large Area Telescope’s silicon tracker and other elements in the same laboratories where they would later build the detectors for IXPE. Testing was meticulous; the team conducted individual trials on each of the tracker’s approximately 10,000 distinct silicon strip detectors before final assembly.

Mid-scale science missions such as Fermi can be challenging, he said, but small missions such as IXPE present their own unique hurdles to overcome.

A man plays a flamethrowing guitar in a backyard.
Baldini plays the flamethrowing guitar presented to him as a gift when he stepped down as Fermi analysis coordinator in 2016. An amateur luthier in his spare time, Baldini builds working guitars as a hobby. (Image courtesy of Luca Baldini)

“On Fermi, we had a bigger budget and longer development time, and given the complexity of the instruments, our agency leads were more amenable to schedule delays,” he said. “We had just three years to deliver IXPE, so we had to find solutions to challenges that upheld the schedule. Our team was very proud, on both sides of the ocean, when we met our goals.”

Baldini, who also chairs IXPE’s Science Analysis and Simulation Working Group, holds a 2001 master’s degree in physics and a 2005 doctorate in applied physics, both from the University of Pisa. He met his wife, fellow IXPE and Fermi researcher Melissa Pesce-Rollins, as postgraduate doctoral students; they married in 2006. “We have offices next to each other and haven’t killed each other yet, so that’s nice,” he chuckled.

With IXPE now in its second year of successful space research, Baldini is already pondering what’s next. His team is supporting a planned Chinese-European mission called the enhanced X-ray Timing and Polarimetry mission (eXTP), designed to study magnetars, neutron stars, supermassive black holes, and other extreme conditions of density, gravity, and magnetism.

But after developing gamma ray and X-ray imaging software and technology for the last 15 years or more, he’s open to all the possibilities of the cosmos.

“I wouldn’t mind changing course completely, pursuing something with more immediate utility for society,” he said. “I like change – different people, different communities, different challenges.”

The cosmos awaits him.

Jonathan Deal
NASA’s Marshall Space Flight Center

From Art to Space: Meet IXPE Flight Controller Kacie Davis

By Rick Smith

If the secret to happiness is pursuing and achieving goals that bring contentment to both the heart and the intellect, then Kacie Davis, a flight controller for NASA’s Imaging X-ray Polarimetry Explorer (IXPE), is living her best life – and she took an unexpected path to get there.

LASP’s Kacie Davis, a women with long hair and glasses, is smiling and is sitting in front of computer screens
IXPE flight controller Kacie Davis discusses the academic journey that took her from earning a fine arts degree to studying astronomy at the University of Colorado-Boulder and then to her role in mission operations at LASP, supporting NASA’s innovative X-ray imaging mission. (Video still courtesy of CU-Boulder)

Initially, it wasn’t the Leawood, Kansas, native’s intent to pursue a STEM career – a path which led her to a seat on console in NASA’s partner organization, the Laboratory for Atmospheric and Space Physics (LASP) on the University of Colorado-Boulder campus.

Davis originally went to school to refine her art skills, earning undergraduate degrees in drawing and photography from Kansas State University in Manhattan, Kansas, and a master’s in studio art from the University of Connecticut in Storrs. Along the way she jockeyed a register at a videogame chain store to pay her rent, taught drawing and multimedia courses at U-Conn, and earned a first-degree black belt in taekwondo.

But some elusive question kept her searching for her professional niche. She had always created “abstract expressionist art that had a tendency to echo what space images look like,” she said. “I kept hearing that in my art critiques – and it slowly piqued my interest in outer space and the universe.” That led her to pursue an astronomy degree at CU-Boulder.

“It felt like this is a place where people get stuff done, and keep getting things done,” she said. “It was inspiring.”

It wasn’t an easy path for an artist whose last mathematics courses had been at least a decade earlier. “I’d never taken physics!” she said. “At first, I wasn’t following a lot of what my classmates and professors were talking about.”

But the science spurred her on – along with the growing desire to help answer some of the oldest universal questions known to humanity, to aid in unlocking secrets of the most powerful and mysterious space phenomena: black holes, quasars, and more. She earned a bachelor’s degree in astronomy in 2020, and became an IXPE flight controller in 2021.

Today, Davis spends much of her time as a flight controller monitoring and directing IXPE’s work as the spacecraft observes and tracks polarized X-rays emitted by powerful celestial objects. Imaging in space is often a one-dimensional process, snapping a photograph and observing the results, but IXPE delves deeper, she said. IXPE measures X-ray polarization, a property of light related to the orientation of the waves’ vibrations.

“Polarimetry is two-dimensional, measuring the direction of X-ray photons flowing away from their source, aiding us in determining brightness and the path of travel, where an object came from and where it might be heading,” she said. “IXPE can even help us measure the spin of black holes – something we’ve never directly measured before. How exciting is that!”

She also regularly works with undergraduate student trainees in the LASP, helping them hone the mission-ops skills that will, in time, enable them to chair a flight controller’s post of their own.

Both aspects of the work, she said, “make me feel like I’m contributing to finding answers to the unknown – which is what I’d been searching for in art. That is quite rewarding.”

In the first months of 2022, Davis was thrilled to be part of the team that helped IXPE acquire its first target of study, Cassiopeia A – the remains of a star that exploded in the 17th century. Ten light-years in diameter, “Cas-A” is a bright ball of superheated gas and glowing cosmic ray particles some 11,000 light-years from Earth.

“We’ve looked at Cas-A a million times, but IXPE showed us more than we’d ever seen before,” Davis said. “It’s a brand-new set of eyes, looking at the universe in a completely new way.”

Not a bad way to describe Davis herself.

IXPE Mission Team Profile: The Laboratory for Atmospheric and Space Physics University of Colorado-Boulder

By Rick Smith

As NASA’s Imaging X-ray Polarimetry Explorer mission explores black holes, neutron stars, and other cosmic phenomena – helping to answer fundamental questions about extreme space environments – it relies on the mission operations team at the Laboratory for Atmospheric and Space Physics, or LASP.

Some 700 people – engineers, scientists, mission-operations personnel and data specialists – staff the Laboratory for Atmospheric and Space Physics, housed on the campus of the University of Colorado-Boulder.

College students sit as computers lined in a row to work on IXPE.
Student command controllers – and aerospace engineering science majors – Adrian Bryant, left, and Rithik Gangopadhyay, center, work with IXPE flight controller Kacie Davis, monitoring NASA’s Imaging X-ray Polarimetry Explorer spacecraft from the mission operations center at the Laboratory for Atmospheric and Space Physics on the campus of the University of Colorado-Boulder. Between 100-150 undergraduate and graduate students help maintain around-the-clock LASP operations. (NASA/CU-Boulder)

For the IXPE mission, LASP flight controllers and support teams monitor and maintain all command and control functions for the spacecraft, as well as planning and scheduling, data integrity, and spacecraft health and safety.

“I get very excited about IXPE science results,” said LASP flight controller Kacie Davis. “IXPE is unique and groundbreaking because it measures polarized X-ray imagery – tracing light back to its source by precisely measuring its brightness and the direction in which photons flow from the source.”

Research leads in the IXPE Science Operations Center at NASA’s Marshall Space Flight Center in Huntsville, Alabama, identify targets and instruct LASP flight controllers to point at them for specific intervals, fine-tune calibrations, and collect the resulting data. All raw-data findings are processed and delivered to the primary IXPE science team within seven days of each completed observation.

Most of the cosmic objects IXPE observes are part of a carefully managed, year-long science operations plan, but the LASP team also may get alerted to reposition the spacecraft to observe unique targets of opportunity, known as “TOOs” in mission-ops vernacular. Such phenomena – a new supernova, perhaps, or an overstuffed black hole trying to digest a neutron star – are rare, but the LASP team is quick to respond, at any hour.

“It’s a lot of work and a quick turnaround, like having a child,” said researcher Stephanie Ruswick, who in late 2022 will succeed LASP’s current flight director, Darren Osborne. “The other night, my 1-year-old slept through the night… but IXPE did not! Our team is always ready to step up and meet those unanticipated requests.”

Trained students on console
The LASP team includes a cadre of CU-Boulder undergraduates, Osborne said – a big advantage for career-minded engineering and science students.

A college aded young woman sits at a computer.
Researcher Stephanie Ruswick, front, LASP’s incoming flight director, oversees IXPE flight operations alongside student lead Alexander Pichler, center, and Rithik Gangopadhyay, both aerospace engineering students at the University of Colorado-Boulder. IXPE – orbiting some 370 miles from Earth – enables researchers to study polarized X-ray emissions from black holes, neutron stars, pulsars, and other sources. (NASA/CU-Boulder)

The summer prior to their junior year, students can enroll in an intensive, 12-week training program to join the team. They train side-by-side with certified LASP command controllers, learning all they can about executing flight operations, monitoring the health of spacecraft in flight, and troubleshooting issues in real time. Each student must complete a checklist of 300 mission-critical tasks on console and pass three written exams.

The paid positions don’t earn the undergrads course credit at the university, “but it gives them a definite leg up on their career goals,” Osborne said. “It’s a big commitment.”

Among those undergraduates now on console is Alexander Pichler, an aerospace engineering senior and the student lead for IXPE. He said there’s no substitute for learning in a practical environment like this one, which complements and informs every facet of his classroom education.

“It really has been an extraordinary opportunity,” said Pichler, now midway through his second year on the LASP team. “Now and then, I step back and think ‘I’m sending commands to a spacecraft that’s up there right now, helping to expand our understanding of the universe.’ It’s a truly horizon-widening experience.”

Davis, who graduated from CU-Boulder in 2020 with a degree in astronomy before joining the mission operations team, agrees.

“We’re doing brand new things that have never been done before, poking at big questions a lot of people shy away from: How is this possible? How can this exist?” she said. “It’s so exciting to be a part of it – helping to further a larger scientific conversation.”

More about LASP
Founded in 1948 on the campus of the University of Colorado-Boulder, LASP initially was known as the Upper Air Laboratory, where scientists studied the upper atmosphere using instruments, stabilizing technologies and pointing platforms of their own design. When researchers spun off in 1956 to form Ball Aerospace & Technologies Corporation in Boulder, the university expanded its own program and renamed the facility.

A team of people of LASP sit at computer desks lined against the wall to work on IXPE.
Credits: LASP

Since then, LASP has sent an instrument to every planet in the solar system and beyond, contributing imaging and sensing data to a variety of high-profile NASA missions, including Galileo, Mariner, Viking, and LADEE. LADEE, flown in 2013 and 2014, helped NASA better understand electrostatically charged dust on the Moon – a crucial need for Artemis-era human exploration of the lunar surface. The LASP team also led mission operations for NASA’s Kepler spacecraft – which identified more than 2,500 verified planets orbiting distant stars from 2009 to 2018.

And the work continues. LASP will participate in the upcoming Near-Earth Object Surveyor mission to spot and track large asteroids and comets that could pose a risk to Earth – and Libera, tracking climate change by documenting energy dispersal from Earth’s atmosphere. Both missions are scheduled to launch later in this decade.

More about IXPE
Managed by Marshall, IXPE is a collaborative effort with LASP; Ball Aerospace; the Italian Space Agency; McGill University in Montreal; Massachusetts Institute of Technology in Cambridge, Massachusetts; Roma Tre University in Rome; Stanford University in Stanford, California; and OHB Italia in Milan, Italy.

Molly Porter
NASA’s Marshall Space Flight Center

IXPE Quickly Observes Aftermath of Exceptional Cosmic Blast

On Oct. 9, 2022, NASA’s Fermi Gamma-ray Space Telescope and Neil Gehrels Swift Observatory detected a high-energy blast of light from deep space. The light came from a powerful explosion called a gamma-ray burst dubbed GRB 221009A that ranks among the most luminous known. Scientists around the world trained their telescopes on the aftermath.

Michela Negro, a postdoctoral research assistant at the University of Maryland Baltimore County and NASA’s Goddard Space Flight Center in Greenbelt, Maryland, could not have been in a better place. She was attending the 10th Fermi Symposium, a gathering of gamma-ray astronomers, in Johannesburg, South Africa. She grabbed two colleagues and started doing the math to see if it might be possible to catch polarized X-rays with the Imaging X-ray Polarimetry Explorer (IXPE).

On a black background, thousands of tiny, blood-red and orange dots encircle a larger, brighter, yellow dot.
The aftermath of GRB 221009A, as seen by NASA’s Imaging X-ray Polarimetry Explorer (IXPE). (Credits: IXPE)

Gamma-ray bursts (GRBs) are unpredictable and fleeting. The IXPE science team had not planned to observe one, but this burst created a unique opportunity. And a quick turnaround was essential.

“We got some promising numbers, so we submitted a target of opportunity request,” said Negro, who led IXPE observation of the burst. This process allows the team to interrupt its long-term plan to retarget for high-interest, time-critical sources.

“In the request you have to justify why you want to point the telescope that way and why so quickly,” Negro continued, “so we just said, ‘This is now or never.’”

For space-based telescopes like IXPE, observing an unplanned target is not as simple as it might sound. It takes a lot of coordination between the IXPE science operations team at NASA’s Marshall Space Flight Center in Alabama, the mission operations manager at Ball Aerospace in Colorado, and the mission operations team at the University of Colorado Boulder’s Laboratory for Atmospheric and Space Physics.

“From the time we got the request until we were observing the target was roughly 36 hours,” said Amy Walden, IXPE’s project manager at Marshall. “The team really did an amazing job. They recognized the incredible opportunity this was, so everyone was working as quickly as they could.”

Stephen Lesage also dropped everything when he learned about the event. Lesage is a graduate research assistant at the University of Alabama in Huntsville and Fermi Gamma-ray Burst Monitor (GBM) team member.

“I was in Atlanta for a Major League Soccer game, but my phone was constantly vibrating with notifications, so I knew it was something big,” Lesage said. “I went back to my hotel room and sat at the desk in the corner until 3 a.m. working on it. But even when the work was done, I couldn’t sleep, I was too excited.”

The signal, originating from the direction of the constellation Sagitta, had traveled an estimated 1.9 billion light years to reach Earth. Astronomers think it could be the birth cry of a new black hole, one that formed in the heart of a massive star collapsing under its own gravity. In these circumstances, a nascent black hole drives powerful jets of particles traveling near the speed of light. The jets pierce through the star, emitting X-rays and gamma rays as they stream into space.

The light from this ancient explosion brings with it new insights into stellar collapse, the birth of a black hole, the behavior and interaction of matter near the speed of light, the conditions in a distant galaxy, and much more. Another GRB this bright may not appear for decades.

“I believe that an event like this won’t happen again in my lifetime,” Negro said.

“It was at least 10 times brighter than the previous record-holder, GRB 130427A,” said GBM Principal Investigator Colleen Wilson-Hodge at Marshall. She also noted that scientists observed an unusually bright and long-lasting afterglow from the burst.

Scientists are still analyzing this data and forming conclusions about what the observations mean. For Walden, it was exciting to see IXPE play a role.

“That’s what IXPE is for: we’re uniquely qualified to search for X-ray polarization,” she said. “GRB 221009A was likely the only chance in our mission lifetime to view one.”

IXPE is a partnership between NASA and the Italian Space Agency.

By Hannah Maginot

IXPE Celebrates 1 Year of Exploring the Cosmos

One year ago, NASA’s Imaging X-ray Polarimetry Explorer (IXPE) lit up the early morning sky as it started its journey into space. The satellite was launched on a Falcon 9 rocket from NASA’s Kennedy Space Center in Florida on Dec. 9, 2021.

A rocket launches, trailed by bright blue and warm white flames that leave a pile of billowy smoke clouds on the ground.
A SpaceX Falcon 9 rocket launches with NASA’s Imaging X-ray Polarimetry Explorer (IXPE) spacecraft onboard from Launch Complex 39A on Dec. 9, 2021, at NASA’s Kennedy Space Center in Florida. (Credits: NASA/Joel Kowsky)

IXPE is the first satellite dedicated to measuring the polarization of X-rays from a variety of cosmic sources, such as black holes and neutron stars. Polarization is a property of light that gives scientists important information about cosmic objects. Before IXPE, X-ray polarization was rarely measured in space. In just one year, IXPE has conducted measurements no telescope has ever been able to make before.

Here’s a look at some of IXPE’s accomplishments in the first year of its mission:

IXPE is just getting started. Its baseline mission duration is two years, so with at least one more year of exploration to go, the satellite is poised to make more exciting discoveries about the intricacies of X-ray polarization. Happy first anniversary, IXPE!

By Hannah Maginot

Meet IXPE Scientist Abel Lawrence Peirson

Artificial intelligence (AI) has led Abel Lawrence Peirson to all kinds of interesting places. He’s used AI techniques to examine brain activity in flies and other neuroscience applications. With the help of AI, he’s even trained a neural network to create internet memes, displaying phrases on images in a way that looks like a human made them to be funny — at least some of the time.

Abel Lawrence Peirson
Abel Lawrence Peirson

Now, Peirson, a doctoral student at Stanford University, is using his AI skills to help solve some the universe’s mysteries through NASA’s Imaging X-Ray Polarimetry Explorer (IXPE) mission. It’s a spacecraft that looks at the polarization of X-rays from extreme objects like supernova remnants, neutron stars, and black holes. Polarization describes how the X-ray light is oriented as it travels through space, offering clues to the physics going on in these extreme objects.

To help scientists analyze and interpret IXPE data, Peirson applies a technique called “supervised machine learning.” That means he trains computer models to reconstruct previous events – in this case, the polarization that led to the patterns of X-ray light detection that IXPE sees. It’s kind of like if you see a dented car next to a pole and could reconstruct exactly how fast, and at what angle, the car hit the pole. “We take a really good simulator of the telescope, and then teach the model to reverse” to figure out what kind of polarization leads to IXPE’s detection’s, Peirson explains.

One of the objects he’s interested in is called a “blazar.” A blazar is a special case of an “active galactic nucleus,” composed of a central supermassive black hole that’s actively feeding off material from a surrounding disk, making it appear very bright in the sky. Jets of high-energy particles spew out, and when the jets are oriented towards us, that makes the object a blazar.

A big mystery about these blazars is whether protons, which are some of the subatomic particles that make up the stuff of the world as we know it, contribute significantly to the energy emission from these jets. Protons are examples of “hadrons,” a type of particle that is made of two or more smaller particles called quarks (you may have heard of the Large Hadron Collider, for example). Hadrons may be colliding with particles of light, called photons, and those clashes would produce particles and light in the jets. “So, if we could measure the polarization, this is a really good probe as to whether there are hadronic processes happening,” Peirson said.

Before he got to work on a space mission, Peirson thought that being a professional scientist would mean more doing math and building computer models. While those skills are important, software programming has turned out to be a huge part of his work. “In the end, if you want to be really impactful nowadays, I think that is sort of reality,” he said. “You need to build usable tools or things that people can build on, and that is, like 99% of the time, software.”

One of the biggest challenges of his work is coordinating with a big collaboration. With lots of team members in multiple countries working on IXPE, Peirson quickly realized that science on this mission is not a solitary endeavor. “You’re part of a team and you need to work within the confines of that team,” he said. “Overall, I’m very happy with how it’s turned out.”’

Peirson is multinational — he grew up in London, but his dad is American, and his mom is Spanish. As a child he loved watching Star Trek and reading Isaac Asimov’s novels, both of which sparked his imagination about space and what might be beyond Earth. After earning his undergraduate degree in physics at the University of Oxford, he pursued a Ph.D. at Stanford in Palo Alto, California, where he’s currently finishing up his dissertation.

His advice to future astrophysicists? Learn statistics and programming as soon as you can. “You’re getting data from the sky, in very weird forms that are very unique and difficult to understand, and then trying use models to understand them,” he said. “And that is essentially data science.”


Elizabeth Landau
NASA Headquarters

IXPE Checks Out X-rays from Extreme Objects

NASA’s Imaging X-ray Polarimetry Explorer (IXPE) mission, a joint effort with the Italian Space Agency, has returned data that no other spacecraft has obtained before from a few extreme cosmic objects.

NASA’s Imaging X-ray Polarimetry Explorer (IXPE)
NASA’s Imaging X-ray Polarimetry Explorer (IXPE)

Launched in December 2021, IXPE has detected polarized X-rays from three of its first six targets. Polarized X-rays carry unique details about where the light comes from and what it passes through. By combining these details with measurements of X-rays’ energy and how they change over time, we get a fuller picture of an object and how it works.

Prior to IXPE, the only cosmic object with polarized X-ray measurements was the Crab Nebula, the wreckage of a massive, exploded star whose light swept past Earth nearly 1,000 years ago. In these new observations, IXPE has confirmed the previous Crab Nebula measurements and detected X-ray polarization from a neutron star and a magnetar. A magnetar is a highly magnetic neutron star, a dense object left in the wake of a stellar explosion.

Scientists are now analyzing these preliminary data to better understand what they mean and how they fit in with other observations of these objects.

“Now in its third month of science operations, IXPE is performing as anticipated and is measuring the X-ray polarization of cosmic sources in the high-energy universe,” said Steve O’Dell, IXPE’s project scientist at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “We are excited to see these new results, about a half-century after the pioneering work of IXPE’s principal investigator Martin Weisskopf and look forward to using this new tool to understand better the workings of neutron stars, black holes, and more.”

Weisskopf was part of a team from Columbia University that first detected polarized X-rays from the Crab Nebula in 1971 using a sounding rocket experiment. About five years later, in 1976 and 1977, the Columbia team used NASA’s eighth Orbiting Solar Observatory (OSO-8) to confirm that X-rays from the Crab Nebula are polarized by a degree of almost 20 percent. IXPE measures the polarization of X-rays with higher precision, but its preliminary results agree with observations from OSO-8 and more recent measurements taken by a small satellite called PolarLight.

Composite image of the Crab Nebula
Composite image of the Crab Nebula with X-rays from NASA’s Chandra X-ray Observatory (blue and white), optical light from NASA’s Hubble Space Telescope (purple), and infrared light from NASA’s Spitzer Space Telescope (pink).
Credits: X-ray: NASA/CXC/SAO; Optical: NASA/STScI; Infrared: NASA-JPL-Caltech

Another object IXPE has looked at recently is the magnetar 4U 0142+61 in the constellation Cassiopeia. The third object that IXPE detected polarized X-rays is the binary accreting neutron star system Hercules X-1, which consists of a low-mass star and a neutron star that is pulling material off it.

The other targets for IXPE’s first science observations were the supernova remnant Cassiopeia A and the active galaxy Centaurus A, as well as the Sagittarius A Complex at the center of the Milky Way, a region that includes the black hole Sagittarius A*. Preliminary analyses have not detected X-ray polarization from these objects so far, but more detailed analyses are underway.

IXPE’s first datasets are now publicly available through NASA’s High Energy Astrophysics Science Archive Research Center, managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland.

IXPE Begins Science Operations

This week, after having spent just over a month in space, IXPE began science operations. The observatory’s boom was deployed successfully on Dec. 15, and the team then spent three weeks checking out the observatory’s maneuvering and pointing abilities and aligning the telescopes. On Jan. 11, IXPE began observing its first official scientific target: Cassiopeia A. Those observations will last about three weeks. Learn more.

Cassiopeia A supernova remnant

IXPE’s first official scientific target is Cassiopeia A, or Cas A, the remains of a massive star that blew itself apart in a supernova around 350 years ago in our own Milky Way galaxy. Supernovae are filled with magnetic energy and accelerate particles to near light-speed, making them laboratories for studying extreme physics in space.

This image shows Cas A as seen by NASA’s Chandra X-ray Observatory. IXPE will provide details about Cas A’s magnetic field structure that can’t be observed in other ways. By studying the X-ray polarization, scientists can work out the detailed structure of its magnetic field and the sites where these particles pick up speed.