Two galaxies seen in a 'joust' preceding a cosmic mega-merger
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."
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
CNA
16-07-2025
- CNA
Astronomers witness birth of solar system for first time
PARIS: Astronomers have, for the first time, observed the earliest stage of planet formation around a distant star, offering fresh insight into how our own solar system may have begun. (Wednesday, July 16) The planetary system is taking shape around HOPS 315, a young star located some 1,300 light years from Earth in the Orion Nebula. HOPS 315 is believed to resemble the Sun in its infancy. PLANETS BORN FROM GAS AND DUST Young stars are typically surrounded by vast rings of gas and dust known as protoplanetary discs, the breeding grounds for new planets. Within these discs, crystalline minerals containing silicon monoxide can clump together, eventually snowballing into kilometre-sized planetesimals. These can go on to become full-fledged planets. In our own solar system, such minerals, the "starter dough" for planets like Earth and Jupiter, are believed to have been trapped inside ancient meteorites. Now, researchers have found similar signs of early planet formation in the disc surrounding HOPS 315. The findings were published in the journal Nature. MINERALS IDENTIFIED BY SPACE AND GROUND TELESCOPES "For the first time, we have identified the earliest moment when planet formation is initiated around a star other than our Sun," said lead study author Melissa McClure of Leiden University in the Netherlands. The James Webb Space Telescope first detected the presence of the minerals. Astronomers then used the European Southern Observatory's ALMA telescope in Chile to pinpoint their location. They found the crystalline minerals clustered in a narrow region of the disc, which bears similarities to the asteroid belt in our own solar system. This discovery could allow scientists to monitor a process that once shaped Earth and its neighbouring planets. "We are seeing a system that looks like what our solar system looked like when it was just beginning to form," said study co-author Merel van 't Hoff of Purdue University in the United States.
CNA
09-07-2025
- CNA
Warming climate, volcanos raise risk of ice falls on Chile's glaciers
SANTIAGO :Chile's glaciers are facing a higher risk of collapse and landslides due to rising temperatures and the country's seismic and volcanic activity, according to an academic study. The study, published in the Journal of South American Earth Sciences in late May, modeled variables such as the possible sudden emptying of glacial lakes, mud and debris flows, avalanches, landslides, or abrupt glacial advances beyond normal speeds. "The study determined that around 10 glaciers ... would be highly susceptible" to one or more of those main destabilizing factors, said geologist Felipe Ugalde of the University of Chile, one of the study's authors. That included some glaciers at risk of ice avalanches, others that had steep overhangs, and some that could be affected by declining glacial lakes. Others faced risk from volcanic eruptions in the nation that sits on the Pacific "Ring of Fire," a belt of volcanos and earthquakes. "Three highly susceptible glaciers are those closest to the main emission centers of the San José volcano, highly susceptible to lahars," Ugalde said, referring to volcanic mud flows that are usually a mix of water, volcanic ash, and rock debris. The geologist added that glaciers globally were retreating amid warming temperatures, causing them to lose mass and become less stable over time. "When temperatures are high, water infiltrates either through rain or through rapid melting of the snowpack. This water percolates into the base of the glacier and acts as a lubricant," Ugalde said, adding this could cause ice to fall off more rapidly in a natural process called calving. "This is ultimately a response to the imbalance that glaciers are experiencing as a result of increasingly higher average air temperatures, even in high mountain environments," he said.
CNA
07-07-2025
- CNA
Alien planet lashed by huge flares from its 'angry beast' star
WASHINGTON :Scientists are tracking a large gas planet experiencing quite a quandary as it orbits extremely close to a young star - a predicament never previously observed. This exoplanet, as planets beyond our solar system are called, orbits its star so tightly that it appears to trigger flares from the stellar surface - larger than any observed from the sun - reaching several million miles (km) into space that over time may strip much of this unlucky world's atmosphere. The phenomenon appears to be caused by the planet's interaction with the star's magnetic field, according to the researchers. And this star is a kind known to flare, especially when young. "A young star of this type is an angry beast, especially if you're sitting as close up as this planet does," said Netherlands Institute for Radio Astronomy astrophysicist Ekaterina Ilin, lead author of the study published in the journal Nature. The star, called HIP 67522, is slightly more massive than the sun and is located about 407 light-years from Earth in the constellation Centaurus. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). This star and planet, as well as a second smaller gas planet also detected in this planetary system, are practically newborns. Whereas the sun and our solar system's planets are roughly 4.5 billion years old, this star is about 17 million years old, with its planets slightly younger. The planet, named HIP 67522 b, has a diameter almost the size of Jupiter, our solar system's largest planet, but with only 5 per cent of Jupiter's mass. That makes it one of the puffiest exoplanets known, with a consistency reminiscent of cotton candy (candy floss). It orbits five times closer to its star than our solar system's innermost planet Mercury orbits the sun, needing only seven days to complete an orbit. A flare is an intense eruption of electromagnetic radiation emanating from the outermost part of a star's atmosphere, called the corona. So how does HIP 67522 b elicit huge flares from the star? As it orbits, it apparently interacts with the star's magnetic field - either through its own magnetic field or perhaps through the presence of conducting material such as iron in the planet's composition. "We don't know for sure what the mechanism is. We think it is plausible that the planet moves within the star's magnetic field and whips up a wave that travels along magnetic field lines to the star. When the wave reaches the stellar corona, it triggers flares in large magnetic field loops that store energy, which is released by the wave," Ilin said. "As it moves through the field like a boat on a lake, it creates waves in its wake," Ilin added. "The flares these waves trigger when they crash into the star are a new phenomenon. This is important because it had never been observed before, especially at the intensity detected." The researchers believe it is a specific type of wave called an Alfvén wave, named for 20th century Swedish physicist and Nobel Prize laureate Hannes Alfvén, that propagates due to the interaction of magnetic fields. The flares may heat up and inflate the planet's atmosphere, which is dominated by hydrogen and helium. Being lashed by these flares could blast away lighter elements from the atmosphere and reduce the planet's mass over perhaps hundreds of millions of years. "At that time, it will have lost most if not all the light elements, and become what's called a sub-Neptune - a gas planet smaller than Neptune," Ilin said, referring to the smallest of our solar system's gas planets. The researchers used observations by two space telescopes: NASA's TESS, short for Transiting Exoplanet Survey Satellite, and the European Space Agency's CHEOPS, short for CHaracterising ExOPlanet Satellite. The plight of HIP 67522 b illustrates the many circumstances under which exoplanets exist. "It is certainly no sheltered youth for this planet. But I am not sad about it. I enjoy diversity in all things nature, and what this planet will eventually become - perhaps a sub-Neptune rich in heavy elements that did not evaporate - is no less fascinating than what we observe today."
