{"id":10002,"date":"2024-01-24T12:00:42","date_gmt":"2024-01-24T16:00:42","guid":{"rendered":"https:\/\/zobi.alcowep.com\/bourtagshdrevxnls658739\/how-nasa-chases-and-investigates-bright-cosmic-blips\/"},"modified":"2024-01-24T12:00:42","modified_gmt":"2024-01-24T16:00:42","slug":"how-nasa-chases-and-investigates-bright-cosmic-blips","status":"publish","type":"post","link":"https:\/\/zobi.alcowep.com\/bourtagshdrevxnls658739\/how-nasa-chases-and-investigates-bright-cosmic-blips\/","title":{"rendered":"How NASA Chases and Investigates Bright Cosmic Blips"},"content":{"rendered":"

How NASA Chases and Investigates Bright Cosmic Blips<\/h2>\n

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9 min read<\/p>\n

How NASA Chases and Investigates Bright Cosmic Blips<\/h1>\n<\/div>\n<\/div>\n<\/div>\n
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\"A<\/figure>
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Astronomers think a long GRB (gamma-ray burst) arises from a massive, rapidly rotating star when its core runs out of fuel and collapses, forming a black hole in the star\u2019s center. In this artist\u2019s concept, two jets emerge from the dying star and interact with surrounding gas and dust.<\/div>\n
NASA\u2019s Goddard Space Flight Center Conceptual Image Lab<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n

Stephen Lesage\u2019s phone started vibrating just after halftime on Oct. 9, 2022, while he was watching a soccer game in Atlanta with a friend. When Lesage saw the incoming messages, the match no longer seemed important. There had been a rare cosmic event, and he needed to get to his computer immediately.<\/p>\n

NASA\u2019s Fermi Gamma-Ray Satellite<\/a> and\u00a0Neil Gehrels Swift Observatory<\/a> had spotted an unusually bright signal in space, and sent automatic alerts to scientists. Lesage\u2019s team\u2019s Fermi chat channel lit up with messages as scientists coordinated their follow-up strategy.<\/p>\n

\u201cEveryone in that group was like, \u2018this thing\u2019s crazy! Who\u2019s on duty to analyze this? This is what we\u2019ve been waiting for,\u2019\u201d Lesage, a graduate student at the University of Alabama, Huntsville, recalled. \u201cTime to go!\u201d<\/p>\n

The unusual event<\/a> turned to be a cosmic burst that may have been the brightest at X-ray and gamma-ray energies since civilization began. Astronomers dubbed it the BOAT, \u201cthe brightest of all time.\u201d Lesage led an analysis of Fermi data that demonstrated just how bright the BOAT really was. More than 150 telescopes in space and on Earth followed up to get more details of the event including NASA\u2019s IXPE (Imaging X-ray Polarimetry Explorer<\/a> ), Hubble Space Telescope<\/a>, and James Webb Space Telescope<\/a>, as well as the European Space Agency\u2019s\u00a0XMM-Newton<\/a>\u00a0telescope.<\/p>\n

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The Universe is Changing<\/strong><\/h2>\n

The BOAT is an example of what astronomers call Time-Domain and Multimessenger Astronomy. The \u201cTime Domain\u201d part refers to events that happen in the universe that telescopes can observe as they unfold, such as a supernova or the merger of two neutron stars. \u201cMultimessenger Astronomy\u201d refers to the variety of \u201cmessengers\u201d that deliver information from the universe, including all forms of light, high-energy particles, and ripples in spacetime called gravitational waves.<\/p>\n

While the universe may seem like it changes extremely slowly, over millions or even billions of years, its celestial occupants do sometimes produce dramatic changes on the order of days or even fractions of seconds. Galactic centers brighten as their central black holes eat material. Black holes siphon plasma from nearby stars. Stars explode. Neutron stars collide with black holes, neutron stars collide with neutron stars, and black holes merge with black holes. Even distant crashes of celestial objects can send powerful ripples that can be detected by space- and ground-based telescopes and instruments. Many of these phenomena are unpredictable in terms of both where and when they might happen next.<\/p>\n

NASA has two \u201cwatchdog\u201d satellites with wide fields of view that send out alerts when they detect a sudden brightening of gamma rays: Fermi and Swift. Fermi\u2019s Gamma-Ray Burst Monitor and Large Area Telescope, and Swift\u2019s Burst Alert Telescope, are key instruments that might be the first to observe these events.<\/p>\n

\u201cWhen something impulsive happens, when something goes boom and explodes or something goes crunch and collapses, they trigger,\u201d said Valerie Connaughton, who leads the high-energy astrophysics portfolio and the Time-Domain and Multimessenger Astronomy Initiative within the Astrophysics Division at NASA Headquarters in Washington.<\/p>\n

Once scientists receive an alert on their computers and phones, they may be able to collaborate with other telescopes to follow up on the event. By using a variety of different space-based observatories and instruments to study these largely unpredictable flashes, scientists can piece together what, where, when, and why they observed a \u201cblip\u201d in the usual calm of space.<\/p>\n

After comparing observations of the BOAT from numerous telescopes, scientists determined that this unusually bright burst came from a supernova and specifically, the core collapse of a massive star rotating rapidly. Later, with data from NASA\u2019s NuSTAR mission, scientists found<\/a> that the jet of material shooting out from the exploding star had a more complicated shape than they originally thought.<\/p>\n

\u201c<\/strong>A giant star just exploded, and we get to study it and figure out what happened, and reverse engineer the pieces and put it back together,\u201d Lesage said.<\/p>\n

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Time-domain astronomy lets us get fundamental answers on the properties of the universe, of fundamental physics itself, and the origin of the elements.\u201d<\/span><\/h2>\n<\/div>\n
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ERIC BURNS<\/p>\n

Astrophysicist, Louisiana State University<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

New Bright Signals <\/strong><\/h2>\n

Just five months after the BOAT, scientists received an alert from Fermi about the second-brightest gamma-ray burst seen in the last 50 years. This newer signal, GRB 230307A<\/a>, which happened in March 2023, joined the BOAT in the category of \u201clong\u201d gamma-ray bursts, lasting 200 seconds, compared to 600 for the BOAT. Thanks to infrared data from NASA\u2019s James Webb Space Telescope, scientists determined that GRB 230307A may have had a very different origin: the merger of two neutron stars about a billion light-years away from Earth. What\u2019s more, Webb detected the rare element tellurium, suggesting that neutron star mergers create heavy elements like this.<\/p>\n

This result still puzzles astronomers such as Eric Burns, a co-author of the GRB 230307A paper and member of the Fermi team at Louisiana State University. Merging neutron stars shouldn\u2019t produce such long gamma-ray bursts, and current models of atomic physics do not entirely explain the mid-infrared wavelengths that Webb detected. He hopes Webb will help us learn more about these kinds of events in the next few years.<\/p>\n

\u201cTime-domain astronomy lets us get fundamental answers on the properties of the universe, of fundamental physics itself, and the origin of the elements,\u201d Burns said.<\/p>\n

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This image from NASA\u2019s James Webb Space Telescope NIRCam (Near-Infrared Camera) instrument highlights Gamma-Ray Burst (GRB) 230307A and its associated kilonova, as well as its former home galaxy, among their local environment of other galaxies and foreground stars. The GRB likely was powered by the merger of two neutron stars. The neutron stars were kicked out of their home galaxy and traveled the distance of about 120,000 light-years, approximately the diameter of the Milky Way galaxy, before finally merging several hundred million years later.<\/div>\n
NASA, ESA, CSA, STScI, A. Levan (Radboud University and University of Warwick)<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n

A Multitude of Messengers<\/strong><\/strong><\/h2>\n

Cosmic \u201cmessengers\u201d associated with fleeting cosmic blips also help scientists reconstruct their origins. The initial 2015 discovery of gravitational waves by LIGO, the Laser Interferometer Gravitational-Wave Observatory, showed that the universe could be observed in a brand new way, and began a new era of possibility for using multiple messengers to study sudden blips in the universe.<\/p>\n

In 2017, scientists demonstrated that potential by combining gravitational wave observations with data from many different ground and space-based observatories to study a kilonova, or neutron star merger, called GW170817. Among the insights from the extensive study of this kilonova, Burns and colleagues used it to make the first precise measurement of the speed of gravity, \u201cthe last major confirmation of a prediction from Einstein,\u201d he said. \u00a0<\/p>\n

Today, the network of the U.S. NSF (National Science Foundation)-supported LIGO, Europe\u2019s VIRGO, and Japan\u2019s KAGRA looks out for gravitational wave events.<\/p>\n

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This animation captures phenomena observed over the course of nine days following the neutron star merger known as GW170817, detected on Aug. 17, 2017. They include gravitational waves (pale arcs), a near-light-speed jet that produced gamma rays (magenta), expanding debris from a kilonova that produced ultraviolet (violet), optical and infrared (blue-white to red) emission, and, once the jet directed toward us expanded into our view from Earth, X-rays (blue).<\/div>\n
NASA\u2019s Goddard Space Flight Center\/Conceptual Image Lab<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n

Light is the only kind of \u201cmessenger\u201d from the universe that has been detected for both the BOAT and the gamma-ray burst that seems to have produced tellurium. An experiment near the South Pole called IceCube, supported by the NSF, looked for high-energy neutrinos coming from the same area of the sky as each event, but did not find any. However, the lack of neutrinos observed helps scientists constrain the possibilities for how these events unfolded.<\/p>\n

\u201cThis multimessenger approach is important, even when you don\u2019t have a detection,\u201d said Michela Negro, astrophysicist and assistant professor at Louisiana State University. \u201cIt really helps rule out some scenarios, on top of telling us something new when we have detections.\u201d<\/p>\n

A Bright Future<\/h2>\n

For Lesage, who is writing his dissertation about the BOAT, time-domain and multimessenger astronomy is an exciting area of study. The BOAT itself is still keeping him and other astronomers busy as they look at all of the processes revealed by the exceptionally bright light from this extreme event. But more transient events are sure to come, and will keep scientists on their toes as they chase after them with a wide variety of telescopes and instruments.<\/p>\n

\u201cThat\u2019s just transient events \u2014 look now or you\u2019re going to miss it,\u201d Lesage said. \u201cLook as quickly as you possibly can.\u201d<\/p>\n

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Doomed neutron stars whirl toward their demise in this illustration. Gravitational waves bleed away orbital energy, causing the stars to move closer together and merge. As they collide, some of the debris blasts away in particle jets moving at nearly the speed of light, producing a brief burst of gamma rays.<\/div>\n
NASA\u2019s Goddard Space Flight Center\/Conceptual Image Lab<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n

Further Reading: Telescopes on the Case<\/h2>\n

In the next few years NASA will be launching new \u201cwatcher\u201d satellites to help look out for sudden transient events like these. They include several CubeSats<\/a>, which are a class of miniaturized spacecraft built in standardized units of cubes around 4 inches (10 cm) on a side:<\/p>\n