A rare and bizarre cosmic event involving three massive black holes has led to the discovery of an unprecedented phenomenon: a supermassive black hole moving at incredible speeds, leaving a 200,000-light-year-long trail of newborn stars in its wake. Captured accidentally by NASA’s Hubble Space Telescope, this extraordinary contrail of star formation is the result of the black hole barreling through intergalactic space and triggering new star formation as it impacts gas ahead of it. The event, described as a game of galactic billiards, is likely the outcome of multiple collisions among supermassive black holes, leaving astronomers eager to investigate further with the James Webb Space Telescope and the Chandra X-ray Observatory.
A Bizarre 200,000-Light-Year-Long Bridge Links a Galaxy to Its Escaping Black Hole
The universe is so capricious that even the slightest things that might go unnoticed could have profound implications. That’s what happened to Yale astronomer Pieter van Dokkum when he was looking through Hubble Space TelescopeThe Hubble Space Telescope (often referred to as Hubble or HST) is one of NASA's Great Observatories and was launched into low Earth orbit in 1990. It is one of the largest and most versatile space telescopes in use and features a 2.4-meter mirror and four main instruments that observe in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. It was named after astronomer Edwin Hubble.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Hubble Space Telescope images and noticed a suspected blemish that looked like a scratch on photographic film. For Hubble’s electronic cameras, cosmic rays skimming along the detector look like “scratches.” But once spectroscopy was done on the oddball streak van Dokkum realized it was really a 200,000-light-yearA light year is the distance that a particle of light (photon) will travel in a year—about 10 trillion kilometers (6 trillion miles). It is a useful unit for measuring distances between stars.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>light-year-long chain of young blue stars located over halfway across the universe! van Dokkum and his colleagues believe that it stretches between a runaway monster back hole and the galaxy it was ejected from. The black holeA black hole is a place in space where the gravitational field is so strong that not even light can escape it. Astronomers classify black holes into three categories by size: miniature, stellar, and supermassive black holes. Miniature black holes could have a mass smaller than our Sun and supermassive black holes could have a mass equivalent to billions of our Sun.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>black hole must be compressing gas along its wake, which condenses to form stars. Nothing like it has ever been seen anywhere else in the universe before.
This is an artist’s impression of a runaway supermassive black hole that was ejected from its host galaxy as a result of a tussle between it and two other black holes. As the black hole plows through intergalactic space it compresses tenuous gas in front to it. This precipitates the birth of hot blue stars. This illustration is based on Hubble Space Telescope observations of a 200,000-light-year-long “contrail” of stars behind an escaping black hole. Credit: NASA, ESA, Leah Hustak (STScI)
Hubble Space Telescope Sees Possible Runaway Black Hole Creating a Trail of Stars
There’s an invisible monster on the loose, barreling through intergalactic space so fast that if it were in our solar system, it could travel from Earth to the Moon in 14 minutes. This supermassive black hole, weighing as much as 20 million Suns, has left behind a never-before-seen 200,000-light-year-long “contrail” of newborn stars, twice the diameter of our Milky WayThe Milky Way is the galaxy that contains our Solar System and is part of the Local Group of galaxies. It is a barred spiral galaxy that contains an estimated 100-400 billion stars and has a diameter between 150,000 and 200,000 light-years. The name "Milky Way" comes from the appearance of the galaxy from Earth as a faint band of light that stretches across the night sky, resembling spilled milk.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Milky Way galaxy. It’s likely the result of a rare, bizarre game of galactic billiards among three massive black holes.
Rather than gobbling up stars ahead of it, like a cosmic Pac-Man, the speedy black hole is plowing into gas in front of it to trigger new star formation along a narrow corridor. The black hole is streaking too fast to take time for a snack. Nothing like it has ever been seen before, but it was captured accidentally by NASAEstablished in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. Its vision is "To discover and expand knowledge for the benefit of humanity." Its core values are "safety, integrity, teamwork, excellence, and inclusion." NASA conducts research, develops technology and launches missions to explore and study Earth, the solar system, and the universe beyond. It also works to advance the state of knowledge in a wide range of scientific fields, including Earth and space science, planetary science, astrophysics, and heliophysics, and it collaborates with private companies and international partners to achieve its goals.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>NASA’s Hubble Space Telescope.
“We think we’re seeing a wake behind the black hole where the gas cools and is able to form stars. So, we’re looking at star formation trailing the black hole,” said Pieter van Dokkum of Yale UniversityEstablished in 1701, Yale University is a private Ivy League research university in New Haven, Connecticut. It is the third-oldest institution of higher education in the United States and is organized into fourteen constituent schools: the original undergraduate college, the Yale Graduate School of Arts and Sciences and twelve professional schools. It is named after British East India Company governor Elihu Yale.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Yale University in New Haven, Connecticut. “What we’re seeing is the aftermath. Like the wake behind a ship we’re seeing the wake behind the black hole.” The trail must have lots of new stars, given that it is almost half as bright as the host galaxy it is linked to.
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The black hole lies at one end of the column, which stretches back to its parent galaxy. There is a remarkably bright knot of ionized oxygen at the outermost tip of the column. Researchers believe gas is probably being shocked and heated from the motion of the black hole hitting the gas, or it could be radiation from an accretion disk around the black hole. “Gas in front of it gets shocked because of this supersonic, very high-velocity impact of the black hole moving through the gas. How it works exactly is not really known,” said van Dokkum.
“This is pure serendipity that we stumbled across it,” van Dokkum added. He was looking for globular star clusters in a nearby dwarf galaxy. “I was just scanning through the Hubble image and then I noticed that we have a little streak. I immediately thought, ‘oh, a cosmic ray hitting the camera detector and causing a linear imaging artifact.’ When we eliminated cosmic rays we realized it was still there. It didn’t look like anything we’ve seen before.”
This Hubble Space Telescope archival photo captures a curious linear feature that is so unusual it was first dismissed as an imaging artifact from Hubble’s cameras. But follow-up spectroscopic observations reveal it is a 200,000-light-year-long chain of young blue stars. A supermassive black hole lies at the tip of the bridge at lower left. The black hole was ejected from the galaxy at upper right. It compressed gas in its wake to leave a long trail of young blue stars. Nothing like this has ever been seen before in the universe. This unusual event happened when the universe was approximately half its current age. Credit: Science: NASA, ESA, Pieter van Dokkum (Yale), Image Processing: Joseph DePasquale (STScI)
Because it was so weird, van Dokkum and his team did follow-up spectroscopy with the W. M. Keck Observatories in Hawaii. He describes the star trail as “quite astonishing, very, very bright and very unusual.” This led to the conclusion that he was looking at the aftermath of a black hole flying through a halo of gas surrounding the host galaxy.
This intergalactic skyrocket is likely the result of multiple collisions of supermassive black holes. Astronomers suspect the first two galaxies merged perhaps 50 million years ago. That brought together two supermassive black holes at their centers. They whirled around each other as a binary black hole.
Then another galaxy came along with its own supermassive black hole. This follows the old idiom: “two’s company and three’s a crowd.” The three black holes mixing it up led to a chaotic and unstable configuration. One of the black holes robbed momentum from the other two black holes and got thrown out of the host galaxy. The original binary may have remained intact, or the new interloper black hole may have replaced one of the two that were in the original binary, and kicked out the previous companion.
When the single black hole took off in one direction, the binary black holes shot off in the opposite direction. There is a feature seen on the opposite side of the host galaxy that might be the runaway binary black hole. Circumstantial evidence for this is that there is no sign of an active black hole remaining at the galaxy’s core. The next step is to do follow-up observations with NASA’s James Webb Space TelescopeThe James Webb Space Telescope (JWST or Webb) is an orbiting infrared observatory that will complement and extend the discoveries of the Hubble Space Telescope. It covers longer wavelengths of light, with greatly improved sensitivity, allowing it to see inside dust clouds where stars and planetary systems are forming today as well as looking further back in time to observe the first galaxies that formed in the early universe.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>James Webb Space Telescope and the Chandra X-ray Observatory to confirm the black hole explanation.
NASA’s upcoming Nancy Grace Roman Space TelescopeThe Nancy Grace Roman Space Telescope (previously known as the Wide Field Infrared Survey Telescope, or WFIRST) is a space telescope that is being developed by NASA. It is named in honor of Nancy Grace Roman, a pioneering astrophysicist who was instrumental in the development of the Hubble Space Telescope. The Roman Space Telescope is designed to study a wide range of cosmic phenomena, including the expansion of the universe, the formation and evolution of galaxies, and the search for exoplanets. It will be equipped with a wide-field camera that will allow it to survey a large portion of the sky and study objects in the infrared part of the electromagnetic spectrum. The Roman Space Telescope is scheduled to be launched in the mid-2020s.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Roman Space Telescope will have a wide-angle view of the universe with Hubble’s exquisite resolution. As a survey telescope, the Roman observations might find more of these rare and improbable “star streaks” elsewhere in the universe. This may require machine learningMachine learning is a subset of artificial intelligence (AI) that deals with the development of algorithms and statistical models that enable computers to learn from data and make predictions or decisions without being explicitly programmed to do so. Machine learning is used to identify patterns in data, classify data into different categories, or make predictions about future events. It can be categorized into three main types of learning: supervised, unsupervised and reinforcement learning.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>machine learning using algorithms that are very good at finding specific weird shapes in a sea of other astronomical data, according to van Dokkum.
The research paper was published on April 6 in The Astrophysical Journal LettersThe Astrophysical Journal Letters (ApJL) is a peer-reviewed scientific journal that focuses on the rapid publication of short, significant letters and papers on all aspects of astronomy and astrophysics. It is one of the journals published by the American Astronomical Society (AAS), and is considered one of the most prestigious journals in the field.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Astrophysical Journal Letters.
Reference: “A Candidate Runaway Supermassive Black Hole Identified by Shocks and Star Formation in its Wake” by Pieter van Dokkum, Imad Pasha, Maria Luisa Buzzo, Stephanie LaMassa, Zili Shen, Michael A. Keim, Roberto Abraham, Charlie Conroy, Shany Danieli, Kaustav Mitra, Daisuke Nagai, Priyamvada Natarajan, Aaron J. Romanowsky, Grant Tremblay, C. Megan Urry and Frank C. van den Bosch, 6 April 2023, The Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/acba86
The Hubble Space Telescope is a project of international cooperation between NASA and ESA. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.
Source: SciTechDaily
