NASA, JAXA XRISM Spots Iron Fingerprints in Nearby Active Galaxy

After starting science operations in February, Japan-led XRISM (X-ray Imaging and Spectroscopy Mission) studied the monster black hole at the center of galaxy NGC 4151.

“XRISM’s Resolve instrument captured a detailed spectrum of the area around the black hole,” said Brian Williams, NASA’s project scientist for the mission at the agency’s Goddard Space Flight Center in Greenbelt, Maryland. “The peaks and dips are like chemical fingerprints that can tell us what elements are present and reveal clues about the fate of matter as it nears the black hole.”

XRISM (pronounced “crism”) is led by JAXA (Japan Aerospace Exploration Agency) in collaboration with NASA, along with contributions from ESA (European Space Agency). It launched Sept. 6, 2023. NASA and JAXA developed Resolve, the mission’s microcalorimeter spectrometer.

NGC 4151 is a spiral galaxy around 43 million light-years away in the northern constellation Canes Venatici. The supermassive black hole at its center holds more than 20 million times the Sun’s mass.

The galaxy is also active, which means its center is unusually bright and variable. Gas and dust swirling toward the black hole form an accretion disk around it and heat up through gravitational and frictional forces, creating the variability. Some of the matter on the brink of the black hole forms twin jets of particles that blast out from each side of the disk at nearly the speed of light. A puffy donut-shaped cloud of material called a torus surrounds the accretion disk.

In fact, NGC 4151 is one of the closest-known active galaxies. Other missions, including NASA’s Chandra X-ray Observatory and Hubble Space Telescope, have studied it to learn more about the interaction between black holes and their surroundings, which can tell scientists how supermassive black holes in galactic centers grow over cosmic time.

The galaxy is uncommonly bright in X-rays, which made it an ideal early target for XRISM.

Resolve’s spectrum of NGC 4151 reveals a sharp peak at energies just under 6.5 keV (kiloelectron volts) — an emission line of iron. Astronomers think that much of the power of active galaxies comes from X-rays originating in hot, flaring regions close to the black hole. X-rays bouncing off cooler gas in the disk causes iron there to fluoresce, producing a specific X-ray peak. This allows astronomers to paint a better picture of both the disk and erupting regions much closer to the black hole.

The spectrum also shows several dips around 7 keV. Iron located in the torus caused these dips as well, although through absorption of X-rays, rather than emission, because the material there is much cooler than in the disk. All this radiation is some 2,500 times more energetic than the light we can see with our eyes.

Iron is just one element XRISM can detect. The telescope can also spot sulfur, calcium, argon, and others, depending on the source. Each tells astrophysicists something different about the cosmic phenomena scattered across the X-ray sky.

XRISM is a collaborative mission between JAXA and NASA, with participation by ESA. NASA’s contribution includes science participation from CSA (Canadian Space Agency).

By Jeanette Kazmierczak
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.

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1942: Engine Roars to Life in First Test at Future NASA Glenn

In a crowded control room on May 8, 1942, National Advisory Committee for Aeronautics (NACA) leaders George Lewis and John Victory pushed a button and spun a crank that activated a massive piston engine in the adjacent test cell of the Engine Propeller Research Building (EPRB). This commenced the first test conducted at the NACA’s Aircraft Engine Research Laboratory (today, NASA’s Glenn Research Center) in Cleveland.

The event was a key milestone for the United States during the otherwise troublesome period that followed the Pearl Harbor attack. Japan’s rapid seizure of large swaths of the Pacific and its capture of 15,000 U.S. troops increased pressure on the NACA to complete its new laboratory. The military needed the new laboratory, whose construction was behind schedule, to improve engine cooling, turbo-supercharging, and fuels for its aircraft, including the revolutionary new Boeing B–29 Superfortress. Besides the EPRB, the hangar was the only other building completed in the 15 months since ground was first broken at the Cleveland site.

Guests coming from Washington, D.C., to witness the first test arrived at the hangar shortly after 9 a.m. that day. They were soon joined by local officials and invited members of the press. Just before 10 a.m., they piled into cars and were driven through the mud to the EPRB, where engineer Arnold Biermann and head mechanic Melvin Harrison had a Wright R-2600 Cyclone engine ready to run. Local politicians and other NACA officials looked on as Lewis and Victory initiated the test, an evaluation of lubricating fuels. Once activated, the engine roared, and banks of instrumentation began capturing the test data for the research engineers.   

Afterward, construction manager Raymond Sharp gave the group a tour of other construction sites at the lab. They then departed to the Union Club downtown for a luncheon, where Victory noted, “We are losing this war at present, and the steel we need for this laboratory is also needed for destroyers in the Atlantic and boats in the Pacific. If the powers that be decide that the steel is more valuable elsewhere in the war effort, we may never finish it.”

Just days later, however, Henry “Hap” Arnold, Commander of the U.S. Army Air Forces, recommended that completion of the laboratory should be prioritized. Congress allocated additional funding, the military provided the necessary supplies, and contractors were pressured to meet their deadlines.

These measures spurred significant progress at the new laboratory. Over the following year, additional facilities were completed, and large groups of employees transferred to Cleveland from Langley Memorial Aeronautical Laboratory (today, NASA’s Langley Research Center in Hampton, Virginia). The effort paid off and, in the end, the NACA met its original deadlines. A formal dedication of the new laboratory took place on May 20, 1943.

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Robert S. Arrighi

International SWOT Mission Can Improve Flood Prediction 

6 Min Read

International SWOT Mission Can Improve Flood Prediction 

A partnership between NASA and the French space agency, the satellite is poised to help improve forecasts of where and when flooding will occur in Earth’s rivers, lakes, and reservoirs.

Rivers, lakes, and reservoirs are like our planet’s arteries, carrying life-sustaining water in interconnected networks. When Earth’s water cycle runs too fast, flooding can result, threatening lives and property. That risk is increasing as climate change alters precipitation patterns and more people are living in flood-prone areas worldwide.

Scientists and water managers use many types of data to predict flooding. This year they have a new tool at their disposal: freshwater data from the Surface Water and Ocean Topography (SWOT) satellite. The observatory, a collaboration between NASA and the French space agency, CNES (Centre National d’Études Spatiales), is measuring the height of nearly all water surfaces on Earth. SWOT was designed to measure every major river wider than about 300 feet (100 meters), and preliminary results suggest it may be able to observe much smaller rivers.

Stream gauges can accurately measure water levels in rivers, but only at individual locations, often spaced far apart. Many rivers have no stream gauges at all, particularly in countries without resources to maintain and monitor them. Gauges can also be disabled by floods and are unreliable when water overtops the riverbank and flows into areas they cannot measure.

SWOT provides a more comprehensive, 3D look at floods, measuring their height, width, and slope. Scientists can use this data to better track how floodwaters pulse across a landscape, improving predictions of where flooding will occur and how often.

Building a Better Flood Model

One effort to incorporate SWOT data into flood models is led by J. Toby Minear of the Cooperative Institute for Research in Environmental Sciences (CIRES) in Boulder, Colorado. Minear is investigating how to incorporate SWOT data into the National Oceanic and Atmospheric Administration’s National Water Model, which predicts the potential for flooding and its timing along U.S. rivers. SWOT freshwater data will fill in spatial gaps between gauges and help scientists like Minear determine the water levels (heights) at which flooding occurs at specific locations along rivers.

He expects SWOT to improve National Water Model data in multiple ways. For example, it will provide more accurate estimates of river slopes and how they change with streamflow. Generally speaking, the steeper a river’s slope, the faster its water flows. Hydrologic modelers use slope data to predict the speed water moves through a river and off a landscape.

SWOT will also help scientists and water managers quantify how much water lakes and reservoirs can store. While there are about 90,000 relatively large U.S. reservoirs, only a few thousand of them have water-level data that’s incorporated into the National Water Model. This limits scientists’ ability to know how reservoir levels relate to surrounding land elevations and potential flooding. SWOT is measuring tens of thousands of U.S. reservoirs, along with nearly all natural U.S. lakes larger than about two football fields combined.

Some countries, including the U.S., have made significant investments in river gauging networks and detailed local flood models. But in Africa, South Asia, parts of South America, and the Arctic, there’s little data for lakes and rivers. In such places, flood risk assessments often rely on rough estimates. Part of SWOT’s potential is that it will allow hydrologists to fill these gaps, providing information on where water is stored on landscapes and how much is flowing through rivers.

Tamlin Pavelsky, NASA’s SWOT freshwater science lead and a researcher at the University of North Carolina at Chapel Hill, says SWOT can help address the growing threat of flooding from extreme storms fueled by climate change. “Think about Houston and Hurricane Harvey in 2017,” he said. “It’s very unlikely we would have seen 60 inches of rain from one storm without climate change. Societies will need to update engineering design standards and floodplain maps as intense precipitation events become more common.”

Pavelsky says these changes in Earth’s water cycle are altering society’s assumptions about floods and what a floodplain is. “Hundreds of millions of people worldwide will be at increased risk of flooding in the future as rainfall events become increasingly intense and population growth occurs in flood-prone areas,” he added.

SWOT flood data will have other practical applications. For example, insurers can use models informed by SWOT data to improve flood hazard maps to better estimate an area’s potential damage and loss risks. A major reinsurance company, FM Global, is among SWOT’s 40 current early adopters — a global community of organizations working to incorporate SWOT data into their decision-making activities.

“Companies like FM Global and government agencies like the U.S. Federal Emergency Management Agency can fine tune their flood models by comparing them to SWOT data,” Pavelsky said. “Those better models will give us a more accurate picture of where and how often floods are likely to happen.”

More About the Mission

Launched on Dec. 16, 2022, from Vandenberg Space Force Base in central California, SWOT is now in its operations phase, collecting data that will be used for research and other purposes.

SWOT was jointly developed by NASA and CNES, with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. NASA’s Jet Propulsion Laboratory, managed for the agency by Caltech in Pasadena, California, leads the project’s U.S. component. For the flight system payload, NASA provided the KaRIn instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. CNES provided the Doppler Orbitography and Radioposition Integrated by Satellite (DORIS) system, dual frequency Poseidon altimeter (developed by Thales Alenia Space), KaRIn radio-frequency subsystem (together with Thales Alenia Space and with support from the UK Space Agency), the satellite platform, and ground operations. CSA provided the KaRIn high-power transmitter assembly. NASA provided the launch vehicle and the agency’s Launch Services Program, based at Kennedy Space Center, and managed the associated launch services.

For more on SWOT, visit:

https://swot.jpl.nasa.gov/

News Media Contact

Jane J. Lee / Andrew Wang

Jet Propulsion Laboratory, Pasadena, Calif.

818-354-0307 / 626-379-6874

jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov

Written by Alan Buis

2024-060

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