NASA Missions Study What May Be a 1-In-10,000-Year Gamma-ray Burst

Mar 29 2023

On Sunday, Oct. 9, 2022, a pulse of intense radiation swept through the solar system so exceptional that astronomers quickly dubbed it the BOAT – the brightest of all time.

The source was a gamma-ray burst (GRB), the most powerful class of explosions in the universe.

The burst triggered detectors on numerous spacecraft, and observatories around the globe followed up. After combing through all of this data, astronomers can now characterize just how bright it was and better understand its scientific impact.

“GRB 221009A was likely the brightest burst at X-ray and gamma-ray energies to occur since human civilization began,” said Eric Burns, an assistant professor of physics and astronomy at Louisiana State University in Baton Rouge. He led an analysis of some 7,000 GRBs – mostly detected by NASA’s Fermi Gamma-ray Space Telescope and the Russian Konus instrument on NASA’s Wind spacecraft – to establish how frequently events this bright may occur. Their answer: once in every 10,000 years.

The burst was so bright it effectively blinded most gamma-ray instruments in space, which means they could not directly record the real intensity of the emission. U.S. scientists were able to reconstruct this information from the Fermi data. They then compared the results with those from the Russian team working on Konus data and Chinese teams analyzing observations from the GECAM-C detector on their SATech-01 satellite and instruments on their Insight-HXMT observatory. Together, they prove the burst was 70 times brighter than any yet seen.

Burns and other scientists presented new findings about the BOAT at the High Energy Astrophysics Division meeting of the American Astronomical Society in Waikoloa, Hawaii. Observations of the burst span the spectrum, from radio waves to gamma rays, and include data from many NASA and partner missions, including the NICER X-ray telescope on the International Space Station, NASA’s NuSTAR observatory, and even Voyager 1 in interstellar space. Papers describing the results presented appear in a focus issue of The Astrophysical Journal Letters.

The signal from GRB 221009A had been traveling for about 1.9 billion years before it reached Earth, making it among the closest-known “long” GRBs, whose initial, or prompt, emission lasts more than two seconds. Astronomers think these bursts represent the birth cries of black holes formed when the cores of massive stars collapse under their own weight. As it quickly ingests the surrounding matter, the black hole blasts out jets in opposite directions containing particles accelerated to near the speed of light. These jets pierce through the star, emitting X-rays and gamma rays as they stream into space.

With this type of GRB, astronomers expect to find a brightening supernova a few weeks later, but so far it has proven elusive. One reason is that the GRB appeared in a part of the sky that’s just a few degrees above the plane of our own galaxy, where thick dust clouds can greatly dim incoming light.

“We cannot say conclusively that there is a supernova, which is surprising given the burst’s brightness,” said Andrew Levan, a professor of astrophysics at Radboud University in Nijmegen, Netherlands. Since dust clouds become more transparent at infrared wavelengths, Levan led near- and mid-infrared observations using NASA’s James Webb Space Telescope – its first use for this kind of study – as well as the Hubble Space Telescope to spot the supernova. “If it’s there, it’s very faint. We plan to keep looking,” he added, “but it’s possible the entire star collapsed straight into the black hole instead of exploding.” Additional Webb and Hubble observations are planned over the next few months.

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As the jets continue to expand into material surrounding the doomed star, they produce a multiwavelength afterglow that gradually fades away.

“Being so close and so bright, this burst offered us an unprecedented opportunity to gather observations of the afterglow across the electromagnetic spectrum and to test how well our models reflect what’s really happening in GRB jets,” said Kate Alexander, an assistant professor in the department of astronomy at the University of Arizona in Tucson. “Twenty-five years of afterglow models that have worked very well cannot completely explain this jet,” she said. “In particular, we found a new radio component we don’t fully understand. This may indicate additional structure within the jet or suggest the need to revise our models of how GRB jets interact with their surroundings.”

The jets themselves were not unusually powerful, but they were exceptionally narrow – much like the jet setting of a garden hose – and one was pointed directly at us, Alexander explained. The closer to head-on we view a jet, the brighter it appears. Although the afterglow was unexpectedly dim at radio energies, it’s likely that GRB 221009A will remain detectable for years, providing a novel opportunity to track the full life cycle of a powerful jet.

The burst also enabled astronomers to probe distant dust clouds in our own galaxy. As the prompt X-rays traveled toward us, some of them reflected off of dust layers, creating extended “light echoes” of the initial blast in the form of X-ray rings expanding from the burst’s location. The X-ray Telescope on NASA’s Neil Gehrels Swift Observatory discovered the presence of a series of echoes. Detailed follow-up by ESA’s (the European Space Agency’s) XMM-Newton telescope, together with Swift data, revealed these extraordinary rings were produced by 21 distinct dust clouds.

“How dust clouds scatter X-rays depends on their distances, the sizes of the dust grains, and the X-ray energies,” explained Sergio Campana, research director at Brera Observatory and the National Institute for Astrophysics in Merate, Italy. “We were able to use the rings to reconstruct part of the burst’s prompt X-ray emission and to determine where in our galaxy the dust clouds are located.”

GRB 221009A is only the seventh gamma-ray burst to display X-ray rings, and it triples the number previously seen around one. The echoes came from dust located between 700 and 61,000 light-years away. The most distant echoes – clear on the other side of our Milky Way galaxy – were also 4,600 light-years above the galaxy’s central plane, where the solar system resides.

Lastly, the burst offers an opportunity to explore a big cosmic question. “We think of black holes as all-consuming things, but do they also return power back to the universe?” asked Michela Negro, an astrophysicist at the University of Maryland, Baltimore County, and NASA’s Goddard Space Flight Center in Greenbelt.

Her team was able to probe the dust rings with NASA’s Imaging X-ray Polarimetry Explorer to glimpse how the prompt emission was organized, which can give insights into how the jets form. In addition, a small degree of polarization observed in the afterglow phase confirms that we viewed the jet almost directly head-on.

Together with similar measurements now being studied by a team using data from ESA’s INTEGRAL observatory, scientists say it may be possible to prove that the BOAT’s jets were powered by tapping into the energy of a magnetic field amplified by the black hole’s spin. Predictions based on such models have already successfully explained other aspects of this burst.

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https://www.nasa.gov/feature/goddard/2023/nasa-missions-study-what-may-be-a-1-in-10000-year-gamma-ray-burst

NASA Receives Top Honor of Best Place to Work in Federal Government

Mar 29, 2023

NASA is taking home the honor of the Best Place to Work in the Federal Government among large agencies for 11 years in a row, as ranked by the Partnership for Public Service.

The rankings, announced Wednesday, reflect the agency’s dedication to pursue missions of discovery and exploration, including sending humans farther into space than ever before for the benefit of humanity.

“In 2022, NASA unfolded the universe with the James Webb Space Telescope, achieved a watershed moment for planetary protection with DART impact, and took a giant leap in our journey back to the Moon and onward to Mars with launch and recovery of the Artemis I flight test. These missions — and every NASA mission — are an achievement made possible by our unrivaled team,” said NASA Administrator Bill Nelson. “The passion and precision of our workforce makes NASA the best place to work in the federal government. Together, we are poised to accomplish more daring feats with new advancements, more scientific contributions on Earth and in the heavens, and more incredible technological breakthroughs that will help shape the 21st century.”

The Best Places to Work in the Federal Government rankings are based on responses to the Office of Personnel Management’s annual Federal Employee Viewpoint Survey from almost 557,778 federal workers and an additional 326,300 employees at 14 agencies that conducted separate surveys at the same time and had a response rate of more than 50%. The Partnership for Public Service began publishing the rankings in 2003.

This year, the Partnership for Public Service and Boston Consulting Group, in collaboration with The Washington Post, released an advanced look at a portion of the 2022 Best Places to Work in the Federal Government rankings and data. This special edition featured the rankings of the top 10 agencies in four categories — large, midsize, and small agencies as well their subcomponents.

https://www.nasa.gov/press-release/nasa-receives-top-honor-of-best-place-to-work-in-federal-government

NASA Releases Agency Climate Strategy

March 29, 2023

NASA has been working to better understand our home planet from the unique vantage point of space since the first TIROS satellites launched in the 1960s. Today, with more than two dozen Earth-observing satellites and instruments, it’s clearer than ever that our planet is an interconnected system. Local events can have global impacts and global events impact local communities. Recognizing that the challenges of today and tomorrow require an agency-wide effort, NASA’s Office of the Chief Scientist established a cross-agency working group and released “Advancing NASA’s Climate Strategy.”

“The last nine years have been the hottest ever recorded. That is simply an indisputable fact, underscoring the need for bold action to protect our planet,” said Administrator Bill Nelson. “NASA’s climate strategy is a declaration of our continued commitment to lead on climate – and how we intend to do so.”

A PDF version of the full “Advancing NASA’s Climate Strategy” document is available here.

The strategy assesses NASA’s climate portfolio across the agency for the first time, extending beyond science and exploration efforts to include every mission directorate and NASA facility.

“The climate and Earth system are changing, and this impacts not only what science we need, but also how we think about our operations and mission safety,” said Kate Calvin, NASA’s chief scientist and senior climate advisor. “This strategy will help NASA integrate our understanding of climate across the agency and in our partnerships to better serve the public.”

The strategy lays out four key priorities for the agency to aide with the integration of climate across NASA: innovate, inform, inspire, and partner. The first priority of innovation relies on continuing NASA’s 60+ years of Earth science studied not only from space – but also through airborne research, direct measurements and field campaigns. With new missions coming online in 2023 to observe air pollution (TEMPO), Earth’s water to help improve climate models (SWOT), and the increasing intensity of storms (TROPICS), NASA-powered observations of our planet are at the core of how we study the effects of climate change.

NASA’s innovation efforts also extend to aeronautics engineering, as NASA seeks to advance the development of greener aerospace technology. Such advances in science and engineering can also lay a foundation for future innovation as NASA technologies and know-how are shared with the world, including agency collaborations to develop remote sensing technology, combat wildfires, and develop space power systems that could advance power alternatives on Earth. Finally, we are working to ensure the sustainability of NASA centers and facilities, including reducing agency greenhouse gas emissions and increasing resiliency to climate variability and change.

The strategy also lays out our commitment to inform the public and decision-makers around the world. NASA is focused on improving the accessibility and usability of climate and Earth science information. From seaside towns who wish to know more about their changing coastlines, to those in wildfire-vulnerable areas, to city-dwellers looking to track smog in their neighborhoods, communities around the world can benefit from NASA’s observations and models to help plan for the future. Providing resources that draw on NASA observations and models can help support everyone in preparing for and responding to climate change.

More than just providing information, one of NASA’s goals is always to inspire and to educate. As we make our observations about Earth accessible to the world, we are also seeking to encourage and train the next generation of climate researchers.

Finally, the strategy discusses the key role that partnering across agencies, institutions, and industries plays in understanding and responding to climate change. NASA will continue and enhance coordination and partnerships with other federal agencies, international entities, and state, local, and tribal governments to deliver actionable climate information to stakeholders – and ensure the broadest applicability of NASA climate information and technologies.

“NASA’s decades-long and vast array of Earth, atmospheric, and solar data have long been one of the foundations of how we understand climate and the Earth system,” said Karen St. Germain, director of NASA’s Earth Science Division. “By studying Earth as a system – from a variety of viewpoints and through many different instruments and scientific fields – NASA’s integrated approach is key for better understanding our home planet. And understanding it gives us the means to better protect it.”

https://climate.nasa.gov/news/3260/nasa-releases-agency-climate-strategy/

https://www.nasa.gov/sites/default/files/atoms/files/advancing_nasas_climate_strategy_2023.pdf