Latest news with #TDEs
Yahoo
06-06-2025
- Science
- Yahoo
Astronomers Just Discovered The Biggest Explosions Since The Big Bang
A never-before-seen type of giant space explosion – the biggest bangs since the Big Bang – has been accidentally captured by the Gaia space telescope. From the hearts of distant galaxies, the mapping telescope recorded sudden, extreme increases in brightness – colossal flares of light that lingered far longer than any such flares had been known to previously. These blasts were calculated to release as much energy as 100 Suns would over the course of their combined lifetimes. Analysis of that light revealed something that was both new and familiar at the same time: stars being torn apart by black holes, but on a scale we hadn't observed before. Each star was a large one, at least three times as massive as the Sun; and each black hole was a supermassive beast lurking in the center of the star's host galaxy. Such events are usually known as tidal disruption events, or TDEs. Astrophysicists are calling these new ones 'extreme nuclear transients' – ENTs for short. "We've observed stars getting ripped apart as tidal disruption events for over a decade, but these ENTs are different beasts, reaching brightnesses nearly 10 times more than what we typically see," says astrophysicist Jason Hinkle of the University of Hawaiʻi's Institute for Astronomy (IfA). "Not only are ENTs far brighter than normal tidal disruption events, but they remain luminous for years, far surpassing the energy output of even the brightest known supernova explosions." The rather tame term 'tidal disruption' is used to describe what gravitational forces do to an object that gets too close to a black hole. At a certain point, the power of the external gravitational field surpasses the gravity holding an object together, and it comes apart in a wild scream of light before at least partially falling into the great unknown beyond the black hole's event horizon. There are telescopes trained on the sky to catch these screams, applying a wide field of view to take in as much of the sky as possible, waiting for those unpredictable flares that denote the death throes of an unlucky star. Astronomers have managed to observe a good number of TDEs, and know roughly how they should play out. There's a sudden brightening in a distant galaxy, with a light curve that rises to a rapid peak before gradually fading over the course of weeks to months. Astronomers can then analyze that light to determine properties such as the relative masses of the objects involved. Gaia was a space telescope whose mission was to map the Milky Way in three dimensions. It spent a great deal of time staring at the sky to capture precise parallax measurements of the stars in the Milky Way. On occasion, however, it managed to exceed its mission parameters. When combing through Gaia data, Hinkle and his colleagues found two strange events: Gaia16aaw, a flare recorded in 2016; and Gaia18cdj, which the telescope caught in 2018. Both events bore a strong similarity to an event recorded by the Zwicky Transient Facility in 2020. Because that event was so insanely powerful, and because it was given the designation ZTF20abrbeie, astronomers nicknamed it "Scary Barbie". Hinkle and his team determined that Gaia16aaw and Gaia18cdj are the same kind of event as Scary Barbie, and set about trying to figure out what caused them. They ruled out supernova explosions – the events were at least twice as powerful as any other known transients, and supernovae have an upper brightness limit. A supernova, the team explained, typically releases as much light as the Sun will in its entire, 10-billion-year lifespan. The output of an ENT, however, is comparable to the lifetime output of 100 Suns all rolled together. Rather, the properties of the ENT events, the researchers found, were consistent with TDEs – just massively scaled up. That includes how much energy is expended, and the shape of the light curve as the event brightens and fades. ENTs are incredibly rare – the team calculated that they are around 10 million times less frequent than supernovae – but they represent a fascinating piece of the black hole puzzle. Supermassive black holes are millions to billions of times the mass of the Sun, and we don't have a clear idea of how they grow. ENTs represent one mechanism whereby these giant objects can pack on mass. "ENTs provide a valuable new tool for studying massive black holes in distant galaxies. Because they're so bright, we can see them across vast cosmic distances – and in astronomy, looking far away means looking back in time," says astrophysicist Benjamin Shappee of IfA. "By observing these prolonged flares, we gain insights into black hole growth during a key era known as cosmic noon, when the universe was half its current age [and] when galaxies were happening places – forming stars and feeding their supermassive black holes 10 times more vigorously than they do today." The research has been published in Science Advances. Titan's Atmosphere 'Wobbles Like a Gyroscope' – And No One Knows Why A 'Crazy Idea' About Pluto Was Just Confirmed in a Scientific First A Giant Mouth Has Opened on The Sun And Even It Looks Surprised
Yahoo
31-05-2025
- General
- Yahoo
Astronomers discover black hole ripping a star apart inside a galactic collision. 'It is a peculiar event'
When you buy through links on our articles, Future and its syndication partners may earn a commission. Astronomers have taken a detailed look at a rare and incredibly violent cosmic event resulting from an unfortunate star venturing too close to a supermassive black hole. The team behind the research hopes it could reveal more about how such events, dubbed "tidal disruption events" or "TDEs," influence the evolution of their host brutal battles between stellar bodies and the immense gravity of black holes with masses millions or even billions of times that of the sun result in stars being shredded and fed to the black holes. This cosmic cannibalism causes blasts of light that can outshine the combined light of every star in the host galaxy of the TDE, alerting scientists to a gory stellar death. This particular TDE has been designated AT 2022wtn, and occurred in a galaxy located around 700 million light-years away. This galaxy is in the early stages of merging with one of its galactic neighbors. The galaxy that hosts the TDE is known as SDSSJ232323.79+104107.7, and it is the smaller of the two colliding galaxies. The other galaxy mixed up in this merger is at least ten times larger than SDSSJ232323.79+104107.7. It is thought that the two galaxies in this merging system have already made a close pass to one other. This represents just the second time that a TDE has been detected in interacting galaxies. That's despite a prevailing theory that the early stages of mergers create the kind of conditions that favor these brutal occurrences. AT 2022wtn was first brought to the attention of astronomers at the Zwicky Transient Facility (ZTF), with further investigation in wavelengths of light ranging from radio to infrared and even X-rays, which revealed its nature as a TDE. The astronomers were able to determine that the black hole involved in this TDE has a mass equal to around 1 million suns, while its stellar meal is a low-mass star. However, despite clearly presenting itself as an example of a supermassive black hole ripping apart a star, there are some unusual aspects of AT 2022wtn that set it apart from other TDEs. "It is a peculiar event. Its light curve is characterized by a plateau in the phase of maximum brightness, lasting about 30 days, accompanied by a sharp drop in temperature and a spectral sequence that shows the development of two emission lines corresponding to the wavelengths of helium and nitrogen," team leader and National Institute for Astrophysics (INAF) Francesca Onori said in a statement. "Something that we had never observed with such clarity." Like all TDEs, AT 2022wtn would have begun when a doomed star's orbit brought it too close to the central supermassive black hole at the heart of its host galaxy. This results in the immense gravitational influence of the black hole generating immense tidal forces within the star. These forces squash the star horizontally while stretching it vertically, a process colorfully known as "spaghettification."Some of the resulting stellar wreckage winds around the destructive supermassive black hole like actual spaghetti around a fork, forming a whirling flattened cloud of plasma called an accretion disk. Not all of the material from the wrecked star falls around the black hole and eventually into its maw, however. A great deal of stellar matter is blasted out as powerful, high-speed outflows or jets. In the case of AT 2022wtn, these outflows created a short, bright radio emission from the TDE and extreme changes in the velocity of light-emitting elements around the also indicated that the star was completely destroyed as a result of this TDE and that, in addition to an accretion disk, the cosmic cannibalistic event created an expanding spherical "bubble" of expelled gas. Related Stories: — Black hole announces itself to astronomers by violently ripping apart a star — Massive star's gory 'death by black hole' is the biggest and brightest event of its kind — Star escapes ravenous supermassive black hole, leaving behind its stellar partner "We found clear traces of the dynamics of the surrounding material also in some emission lines which show characteristics compatible with a fast propagation towards the outside," Onori said. "Thanks to our monitoring campaign, we were able to propose an interpretation of the origin of the observed radiation: AT2022wtn gave rise to a rapid formation of the disk around the black hole and the subsequent expulsion of part of the stellar matter. "This result is particularly relevant, since the source of visible light and the physical conditions of the region from which it comes, in TDEs, are still under study."The team's research was published on May 23 in the journal Monthly Notices of the Royal Astronomical Society.
Yahoo
13-05-2025
- Science
- Yahoo
Hubble Telescope sees wandering black hole slurping up stellar spaghetti
When you buy through links on our articles, Future and its syndication partners may earn a commission. Astronomers have caught a black hole far from the center of its home galaxy ripping a star to shreds — providing, for the first time, direct evidence of a rogue supermassive black hole in action. The event, named AT2024tvd, took place approximately 600 million light-years from Earth. Despite weighing about a million times the mass of our sun, the black hole wasn't found at the center of its host galaxy, where such giants typically reside. It marks the first known instance of an "off-center" tidal disruption event (TDE), a phenomenon where a star is stretched and torn apart — or spaghettified — by a black hole's immense gravity. Astronomers say the find opens the door for tracking down other rogue TDEs. "I think this discovery will motivate scientists to look for more examples of this type of event," Yuhan Yao, a postdoctoral fellow in the department of astronomy at the University of California, Berkeley, who led the study, said in a NASA statement. The sudden, bright flare from the event was picked up by the Zwicky Transient Facility, a sky-surveying optical camera mounted on a telescope at the Palomar Observatory near San Diego. Follow-up observations by the Hubble Space Telescope revealed that this black hole lies 2,600 light-years from the galaxy's core, where a much larger black hole resides — a behemoth 100 million times the mass of the sun. The presence of two massive black holes in a single galaxy isn't unexpected, astronomers say. Most large galaxies contain at least one supermassive black hole at their center. Because galaxies frequently collide and merge over cosmic timescales, astronomers have long speculated that some galaxies might harbor multiple black holes, at least until they eventually collide and merge into an even larger black hole. These hidden giants typically remain quiet, only revealing themselves when they consume nearby stars or gas clouds, producing a brief burst of light. But catching these black holes in action is incredibly rare. Astronomers estimate that a massive black hole consumes a star approximately once every 30,000 years. These events "hold great promise for illuminating the presence of massive black holes that we would otherwise not be able to detect," Ryan Chornock, a professor of astronomy at the University of California, Berkeley, said in the same statement. "Theorists have predicted that a population of massive black holes located away from the centers of galaxies must exist, but now we can use TDEs to find them." RELATED STORIES: — Star escapes ravenous supermassive black hole, leaving behind its stellar partner — Astronomers witness 18 ravenous black holes ripping up and devouring stars — Mystery solved? Runaway black hole chased by tail of stars may be galaxy in disguise While the presence of two supermassive black holes in a single galaxy isn't surprising, the fact that this one is not gravitationally bound to the galaxy's core raises intriguing questions about its history. For one, astronomers are uncertain how this "rogue" black hole ended up so far from the center. One theory is that it was ejected during a violent cosmic interaction involving multiple black holes. Another possibility is that it came from a smaller galaxy that merged with the larger one over a billion years ago. If this rogue black hole was indeed a remnant of a past merger, it may eventually drift inward and merge with the larger black hole at the galaxy's center, according to the statement. Such a merger would release powerful gravitational waves, ripples in spacetime that could one day be detected by future space-based observatories such as the Laser Interferometer Space Antenna (LISA), scheduled for launch in 2035. This research is described in a paper accepted for publication in The Astrophysical Journal Letters.
