Latest news with #SgrA
Time of India
27-05-2025
- Science
- Time of India
Astronomers stunned as sleeping Black Hole roars back to life after 20 years
The night sky was once thought of as a calm, unchanging dome, but over the years, it has become a dynamic canvas for discovery. Modern telescopes like the Zwicky Transient Facility (ZTF) are now looking deep into the night sky and the cosmos in real time, capturing sudden flashes, flares, and transformations as they happen. The advancement in technology every day is giving ways to observe the universe and witness cosmic events that happen over days, weeks, or even years, events that were previously considered too rare or distant to catch in action. One such surprise came up during late 2019, when a quiet galaxy, SDSS1335+0728, suddenly lit up in the Virgo constellation, located about 300 million light-years from Earth. What followed has kept astronomers captivated for over four years, and the show isn't over yet. What is happening in the cosmos? In December 2019, astronomers spotted that the quiet core of SDSS1335+0728, a spiral galaxy in the Virgo constellation, suddenly brightened by several orders of magnitude. Located about 300 million light-years away, this galaxy had shown no signs of activity for over two decades. Now, its center home to a supermassive black hole roughly a million times the mass of the Sun was blazing to life. Astronomers immediately suspected either a tidal disruption event, where a star gets torn apart by a black hole's gravity, or the first signs of an active galactic nucleus (AGN) waking up. But what made this case unusual was the duration. More than four years later, the flare hasn't faded, far exceeding the timescale of typical star-eating episodes or supernovae. 'This behavior is unprecedented,' said Paula Sánchez Sáez, lead author of the study published in Astronomy & Astrophysics and an astronomer at the European Southern Observatory (ESO) in Germany. Instruments including ESO's X-shooter spectrograph detected a consistent rise in ultraviolet, optical, and infrared light—and in February 2024, X-ray emissions began for the first time. The spectrum now reveals broad emission lines, meaning gas moving near light-speed close to the black hole. 'Suddenly, its core starts showing dramatic changes in brightness, unlike any typical event we've seen before,' Sánchez Sáez added. Co-author Lorena Hernández García of the Millennium Institute of Astrophysics (MAS) in Chile noted, 'If so, this would be the first time that we see the activation of a massive black hole in real time.' There is a new nuclear activity in space That makes SDSS1335+0728 a cosmic rarity. It doesn't shine as brightly as classic quasars, but its persistence rules out most common flare types. It sits in a gray area, possibly marking a new category of nuclear activity. 'This could also happen to our own Sgr A*, the massive black hole at the center of our galaxy,' said Claudio Ricci of Diego Portales University in Chile. 'But it's unclear how likely that is.' Researchers are now trying to determine whether this is a very slow tidal disruption, the birth of a new accretion disk, or something never seen before. Each scenario could reshape models of how supermassive black holes evolve today. 'We expect that instruments such as MUSE on the VLT and those on the upcoming Extremely Large Telescope will be key to understanding why the galaxy is brightening,' said Sánchez Sáez.
Ammon
22-05-2025
- Science
- Ammon
Two galaxies seen in a 'joust' preceding a cosmic mega-merger
Ammon News - Astronomers have observed two distant galaxies - both possessing roughly as many stars as our Milky Way - careening toward each other before their inevitable merger at a time when the universe was about a fifth its current age, a scene resembling two knights charging in a joust. The galaxies, observed using two Chile-based telescopes, were seen as they existed about 11.4 billion years ago, approximately 2.4 billion years after the Big Bang event that initiated the universe. At the heart of one of the galaxies resides a quasar, a highly luminous object powered by gas and other material falling into a supermassive black hole. The intense radiation across the electromagnetic spectrum unleashed by the quasar is seen disrupting clouds of gas and dust, known as molecular clouds, in the other galaxy. It is molecular clouds that give rise to stars. But the effects of the quasar's radiation turned the clouds in the affected region into "only tiny dense cloudlets that are too small to form stars," said astrophysicist Sergei Balashev of the Ioffe Institute in Saint Petersburg, Russia, co-lead author of the study published on Wednesday in the journal Nature, opens new tab. This is the first time such a phenomenon has been observed, Balashev said. Stars form by the slow contraction under gravity of these clouds, with small centers taking shape that heat up and become new stars. But the galaxy affected by the quasar's radiation was left with fewer regions that could serve as such stellar nurseries, undermining its star formation rate. The interaction between the two galaxies reminded the researchers of a medieval joust. "Much like jousting knights charging toward one another, these galaxies are rapidly approaching. One of them - the quasar host - emits a powerful beam of radiation that pierces the companion galaxy, like a lance. This radiation 'wounds' its 'opponent' as it disrupts the gas," said astronomer and co-lead author Pasquier Noterdaeme of the Paris Institute of Astrophysics in France. You might think that a mummified corpse would have a fairly unpleasant stink. Supermassive black holes are found at the heart of many galaxies, including the Milky Way. The researchers estimated the mass of the one that serves as the engine of the quasar studied in this research at about 200 million times that of our sun. The intense gravitational strength of the supermassive black hole pulls gas and other material toward it. As this stuff spirals inward at high speed, it heats up due to friction, forming a disk that emits extremely powerful radiation in two opposite directions, called biconical beams. The ultraviolet light from one of these beams is what played havoc with the gas in the companion galaxy. This supermassive black hole is much more massive than the one at the center of the Milky Way - called Sagittarius A*, or Sgr A* - which possesses roughly 4 million times the mass of the sun and is located about 26,000 light-years from Earth. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). The researchers used the Atacama Large Millimeter/submillimeter Array, or ALMA, to characterize the two galaxies and used the European Southern Observatory's Very Large Telescope, or VLT, to probe the quasar as well as the gas in the companion galaxy. The configuration of the galaxies as viewed from the perspective of Earth enabled the researchers to observe the radiation from the quasar passing directly through the companion galaxy. Most galactic mergers that have been observed by astronomers occurred later in the history of the universe. "Galaxies are typically found in groups, and gravitational interactions naturally lead to mergers over cosmic time," Noterdaeme said. "In line with current understanding, these two galaxies will eventually coalesce into a single larger galaxy. The quasar will fade as it exhausts the available fuel." Reuters
Korea Herald
22-05-2025
- Science
- Korea Herald
Two Galaxies in 'joust' before mega-merger
WASHINGTON (Reuters) — Astronomers have observed two distant galaxies — both possessing roughly as many stars as our Milky Way — careening toward each other before their inevitable merger at a time when the universe was about a fifth its current age, a scene resembling two knights charging in a joust. The galaxies, observed using two Chile-based telescopes, were seen as they existed about 11.4 billion years ago, approximately 2.4 billion years after the Big Bang event that initiated the universe. At the heart of one of the galaxies resides a quasar, a highly luminous object powered by gas and other material falling into a supermassive black hole. The intense radiation across the electromagnetic spectrum unleashed by the quasar is seen disrupting clouds of gas and dust, known as molecular clouds, in the other galaxy. It is molecular clouds that give rise to stars. But the effects of the quasar's radiation turned the clouds in the affected region into "only tiny dense cloudlets that are too small to form stars," said astrophysicist Sergei Balashev of the Ioffe Institute in Saint Petersburg, Russia, co-lead author of the study published on Wednesday in the journal Nature. This is the first time such a phenomenon has been observed, Balashev said. Stars form by the slow contraction under gravity of these clouds, with small centers taking shape that heat up and become new stars. But the galaxy affected by the quasar's radiation was left with fewer regions that could serve as such stellar nurseries, undermining its star formation rate. The interaction between the two galaxies reminded the researchers of a medieval joust. "Much like jousting knights charging toward one another, these galaxies are rapidly approaching. One of them — the quasar host — emits a powerful beam of radiation that pierces the companion galaxy, like a lance. This radiation 'wounds' its 'opponent' as it disrupts the gas," said astronomer and co-lead author Pasquier Noterdaeme of the Paris Institute of Astrophysics in France. Supermassive black holes are found at the heart of many galaxies, including the Milky Way. The researchers estimated the mass of the one that serves as the engine of the quasar studied in this research at about 200 million times that of our sun. The intense gravitational strength of the supermassive black hole pulls gas and other material toward it. As this stuff spirals inward at high speed, it heats up due to friction, forming a disk that emits extremely powerful radiation in two opposite directions, called biconical beams. The ultraviolet light from one of these beams is what played havoc with the gas in the companion galaxy. This supermassive black hole is much more massive than the one at the center of the Milky Way — called Sagittarius A*, or Sgr A* — which possesses roughly 4 million times the mass of the sun and is located about 26,000 light-years from Earth. A light-year is the distance light travels in a year, 9.5 trillion kilometers. The researchers used the Atacama Large Millimeter/submillimeter Array, or ALMA, to characterize the two galaxies and used the European Southern Observatory's Very Large Telescope, or VLT, to probe the quasar as well as the gas in the companion galaxy. The configuration of the galaxies as viewed from the perspective of Earth enabled the researchers to observe the radiation from the quasar passing directly through the companion galaxy. Most galactic mergers that have been observed by astronomers occurred later in the history of the universe. "Galaxies are typically found in groups, and gravitational interactions naturally lead to mergers over cosmic time," Noterdaeme said. "In line with current understanding, these two galaxies will eventually coalesce into a single larger galaxy. The quasar will fade as it exhausts the available fuel."
Yahoo
21-05-2025
- Science
- Yahoo
Two galaxies seen in a 'joust' preceding a cosmic mega-merger
By Will Dunham WASHINGTON (Reuters) - Astronomers have observed two distant galaxies - both possessing roughly as many stars as our Milky Way - careening toward each other before their inevitable merger at a time when the universe was about a fifth its current age, a scene resembling two knights charging in a joust. The galaxies, observed using two Chile-based telescopes, were seen as they existed about 11.4 billion years ago, approximately 2.4 billion years after the Big Bang event that initiated the universe. At the heart of one of the galaxies resides a quasar, a highly luminous object powered by gas and other material falling into a supermassive black hole. The intense radiation across the electromagnetic spectrum unleashed by the quasar is seen disrupting clouds of gas and dust, known as molecular clouds, in the other galaxy. It is molecular clouds that give rise to stars. But the effects of the quasar's radiation turned the clouds in the affected region into "only tiny dense cloudlets that are too small to form stars," said astrophysicist Sergei Balashev of the Ioffe Institute in Saint Petersburg, Russia, co-lead author of the study published on Wednesday in the journal Nature. This is the first time such a phenomenon has been observed, Balashev said. Stars form by the slow contraction under gravity of these clouds, with small centers taking shape that heat up and become new stars. But the galaxy affected by the quasar's radiation was left with fewer regions that could serve as such stellar nurseries, undermining its star formation rate. The interaction between the two galaxies reminded the researchers of a medieval joust. "Much like jousting knights charging toward one another, these galaxies are rapidly approaching. One of them - the quasar host - emits a powerful beam of radiation that pierces the companion galaxy, like a lance. This radiation 'wounds' its 'opponent' as it disrupts the gas," said astronomer and co-lead author Pasquier Noterdaeme of the Paris Institute of Astrophysics in France. Supermassive black holes are found at the heart of many galaxies, including the Milky Way. The researchers estimated the mass of the one that serves as the engine of the quasar studied in this research at about 200 million times that of our sun. The intense gravitational strength of the supermassive black hole pulls gas and other material toward it. As this stuff spirals inward at high speed, it heats up due to friction, forming a disk that emits extremely powerful radiation in two opposite directions, called biconical beams. The ultraviolet light from one of these beams is what played havoc with the gas in the companion galaxy. This supermassive black hole is much more massive than the one at the center of the Milky Way - called Sagittarius A*, or Sgr A* - which possesses roughly 4 million times the mass of the sun and is located about 26,000 light-years from Earth. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). The researchers used the Atacama Large Millimeter/submillimeter Array, or ALMA, to characterize the two galaxies and used the European Southern Observatory's Very Large Telescope, or VLT, to probe the quasar as well as the gas in the companion galaxy. The configuration of the galaxies as viewed from the perspective of Earth enabled the researchers to observe the radiation from the quasar passing directly through the companion galaxy. Most galactic mergers that have been observed by astronomers occurred later in the history of the universe. "Galaxies are typically found in groups, and gravitational interactions naturally lead to mergers over cosmic time," Noterdaeme said. "In line with current understanding, these two galaxies will eventually coalesce into a single larger galaxy. The quasar will fade as it exhausts the available fuel."
Yahoo
25-03-2025
- Science
- Yahoo
Scientists Intrigued by "Star Grinder" Pulverizing Entire Star Systems in Our Galaxy
Astronomers suggest there's a giant "star grinder" lurking at the center of the Milky Way, churning up potentially tens of thousands of star systems that are unfortunate enough to get too close. As detailed in a new paper to be published in the journal Astronomy & Astrophysics and first spotted by Universe Today, astronomers in the Czech Republic and Germany suggest that B-type stars, which are only a few times the mass of the Sun, as well as much heavier O-type stars, are being blended up with tens of thousands of smaller black holes near Sagittarius A*, the supermassive black hole at the center of our galaxy. According to the theory, only the smaller and older B-type stars can survive this ordeal, with the much more massive O-type stars succumbing to their early demise less than five million years into their lifespan — and turning into more small black holes in the maelstrom instead. The research could force us to reconsider what we know about the violent events happening at the center of our galaxy — a brutal cycle of life and death, right at the core of the Milky Way. The research could also explain an observation that has puzzled astronomers for years. Within less than a tenth of a light-year from Sagittarius*, O-type stars are nowhere to be found. B-type stars, however, are the predominant type so close to the giant black hole, many of which have been observed to be ejected from the center at extremely fast speeds. "The smaller B-stars can survive much longer, in fact for some 50 million years," said lead author and Charles University, Czechia, astronomy PhD Jaroslav Haas in a statement. "This explains why the heavy O-type stars are missing at distances smaller than about one-tenth of a light year from SgrA*, with only B-stars surviving there." "These results give us an entirely new understanding of the immediate surroundings of the central super-massive black hole," explained coauthor and Charles University astrophysicist Pavel Kroupa. Haas and his colleagues found that the density of black holes actually increases as you move away from the galactic center, before dropping again at a certain distance. Such a density profile is a "result of the complicated dynamical processes near the central super-massive black hole and our results will allow us to perform new computer simulations to better understand these," explained coauthor and head of the Charles University Astronomical Institute Ladislav Šubr. The researchers are now excited to better understand the "violent pack of thousands of black holes at the center of our Galaxy that is continuously destroying the stars down there," according to coauthor and Charles University astronomer Myank Singhal. More on Sagittarius A*: Scientists Capture Amazing Image of Black Hole at Center of Our Galaxy
