An international group of astrophysicists led by Radboud University in the Netherlands discovered an unique mechanism that ruins stars and generates a gamma-ray burst (GRB). (Artistic illustration of a gamma-ray burst.) Credit: International Gemini Observatory/NOIRLab/NSF/ AURA/M. Garlick/M. Zamani
Astrophysicists have discovered a new system for star damage and gamma-ray burst generation, originating from excellent collisions in the dense environments near supermassive great voids in ancient galaxies. This finding, released in Nature Astronomy, boosts our understanding of star deaths and might point to formerly unknown sources of gravitational waves.
While looking for the origins of an effective gamma-ray burst (GRB), a worldwide group of astrophysicists might have come across a brand-new way to ruin a star.
Many GRBs originate from taking off neutron-star mergers or enormous stars, the researchers concluded that GRB 191019A instead came from the accident of stars or stellar remnants in the loaded environment surrounding a supermassive black hole at the core of an ancient galaxy. The demolition derby-like environment points to a long-hypothesized– but never-before-seen– way to destroy a star and generate a GRB.
The research study was released on June 22 in the journal Nature Astronomy. Led by Radboud University in the Netherlands, the research study team consisted of astronomers from Northwestern University.
” For every hundred events that fit into the conventional category plan of gamma-ray bursts, there is at least one oddball that throws us for a loop,” said Northwestern astrophysicist and study co-author Wen-fai Fong, “However, it is these oddballs that tell us the most about the amazing variety of explosions that deep space is capable of.”
” The discovery of these remarkable phenomena within thick outstanding systems, especially those surrounding supermassive black holes at the cores of galaxies, is undoubtedly exciting,” stated Northwestern astrophysicist and research study co-author Giacomo Fragione. “This impressive discovery grants us an alluring look into the intricate characteristics at work within these cosmic environments, establishing them as factories of occasions that would otherwise be deemed difficult.”
This artists impression illustrates how astronomers studying an effective gamma-ray burst (GRB) with the Gemini South telescope, run by NSFs NOIRLab, might have discovered a never-before-seen way to destroy a star. Unlike a lot of GRBs, which are brought on by taking off massive stars or the possibility mergers of neutron stars, astronomers have actually concluded that this GRB came instead from the collision of stars or stellar residues in the packed environment surrounding a supermassive great void at the core of an ancient galaxy.
Fong is an assistant teacher of physics and astronomy at Northwesterns Weinberg College of Arts and Sciences and a member of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). Fragione is a research study assistant professor in CIERA. Other Northwestern co-authors consist of Anya Nugent and Jillian Rastinejad– both Ph.D. students in astronomy and members of Fongs research study group.
When relatively low-mass stars like our sun reach old age, they shed their external layers, eventually fading to become white dwarf stars. More huge stars, on the other hand, burn brighter and take off quicker in cataclysmic supernovae explosions, producing ultra-dense items like neutron stars and black holes.
The brand-new study finds there may be a fourth choice.
” Our outcomes reveal that stars can meet their demise in some of the densest regions of deep space, where they can be driven to clash,” said lead author Andrew Levan, an astronomer with Radboud University. “This is amazing for understanding how stars die and for addressing other concerns, such as what unexpected sources might produce gravitational waves that we could spot in the world.”
Long past their star-forming prime, ancient galaxies have few, if any, staying massive stars. Their cores, however, teem with stars and a menagerie of ultra-dense outstanding residues, such as white overshadows, neutron stars, and great voids. Astronomers have long believed that in the turbulent beehive of activity surrounding a supermassive great void, it only would be a matter of time before two stellar things clashed to produce a GRB. However proof for that kind of merger has actually stayed elusive.
On Oct. 19, 2019, astronomers glimpsed the very first hints of such an occasion when NASAs Neil Gehrels Swift Observatory discovered a bright flash of gamma rays that lasted a little over one minute. Any GRB lasting longer than two seconds is considered “long.” Such bursts normally originate from the collapse of stars a minimum of 10 times the mass of our sun.
The scientists then used the Gemini South telescope in Chile– part of the International Gemini Observatory operated by the National Science Foundations NOIRLab– to make long-term observations of the GRBs fading afterglow.
These observations enabled the astronomers to pinpoint the location of the GRB to an area less than 100 light-years from the nucleus of an ancient galaxy– extremely near the galaxys supermassive black hole. Oddly, the researchers also discovered no proof of a corresponding supernova, which would leave its imprint on the light caught by Gemini South.
” The lack of a supernova accompanying the long GRB 191019A informs us that this burst is not a common huge star collapse,” stated Rastinejad, who performed estimations to ensure a supernova was not hiding within the information. “The location of GRB 191019A, embedded in the nucleus of the host galaxy, teases an anticipated however not yet evidenced theory for how gravitational-wave giving off sources might form.”
In typical stellar environments, the production of long GRBs from colliding stellar residues, such as neutron stars and black holes, is extremely rare. The cores of ancient galaxies, nevertheless, are anything but normal, and there might be a million or more stars packed into a region just a few light-years throughout. Such extreme population density might be terrific sufficient that occasional outstanding accidents can occur, particularly under the titanic gravitational influence of a supermassive black hole, which would trouble the motions of stars and send them careening in random instructions. Ultimately, these wayward stars would intersect and merge, setting off a titanic explosion that could be observed from huge cosmic ranges.
” The discovery of this occasion in the core of its old, quiescent galaxy unlocks to promising brand-new opportunities for the formation of binary systems that have rarely been observed before.”– Anya Nugent, Ph.D. trainee in astronomy
” This event confuses nearly every expectation we have for the environments of short and long GRBs,” said Nugent, who carried out crucial modeling of the host galaxy. “While long GRBs are never ever found in galaxies as dead and old as GRB 191019As host, brief GRBs, with their merger origins, have not been observed to be so linked to their hosts nuclei. The discovery of this event in the core of its old, quiescent galaxy unlocks to promising new avenues for the formation of binary systems that have actually seldom been observed before.”
It is possible that such events take place routinely in similarly crowded regions across deep space but have gone undetected up until this point. A possible reason for their obscurity is that galactic centers are brimming with dust and gas, which might obscure both the initial flash of the GRB and the resulting afterglow. GRB 191019A may be an unusual exception, enabling astronomers to find the burst and study its consequences.
” While this event is the very first of its kind to be discovered, its possible there are more out there that are concealed by the large amounts of dust close to their galaxies,” Fong said. “Indeed, if this long-duration event originated from combining compact things, it contributes to the growing population of GRBs that defies our conventional classifications.”
By working to find more of these events, the researchers wish to match a GRB detection with a matching gravitational-wave detection, which would expose more about their real nature and validate their origins– even in the murkiest of environments. The Vera C. Rubin Observatory, when it comes online in 2025, will be important in this kind of research.
Referral: “A long-duration gamma-ray burst of dynamical origin from the nucleus of an ancient galaxy” by Andrew J. Levan, Daniele B. Malesani, Benjamin P. Gompertz, Anya E. Nugent, Matt Nicholl, Samantha R. Oates, Daniel A. Perley, Jillian Rastinejad, Brian D. Metzger, Steve Schulze, Elizabeth R. Stanway, Anne Inkenhaag, Tayyaba Zafar, J. Feliciano Agüí Fernández, Ashley A. Chrimes, Kornpob Bhirombhakdi, Antonio de Ugarte Postigo, Wen-fai Fong, Andrew S. Fruchter, Giacomo Fragione, Johan P. U. Fynbo, Nicola Gaspari, Kasper E. Heintz, Jens Hjorth, Pall Jakobsson, Peter G. Jonker, Gavin P. Lamb, Ilya Mandel, Soheb Mandhai, Maria E. Ravasio, Jesper Sollerman and Nial R. Tanvir, 22 June 2023, Nature Astronomy.DOI: 10.1038/ s41550-023-01998-8.
An international group of astrophysicists led by Radboud University in the Netherlands found an unique mechanism that destroys stars and produces a gamma-ray burst (GRB). When fairly low-mass stars like our sun reach old age, they shed their outer layers, eventually fading to become white dwarf stars. More huge stars, on the other hand, burn brighter and take off faster in cataclysmic supernovae explosions, producing ultra-dense items like neutron stars and black holes. Their cores, nevertheless, teem with stars and a menagerie of ultra-dense excellent remnants, such as white overshadows, neutron stars, and black holes. In typical galactic environments, the production of long GRBs from colliding excellent remnants, such as neutron stars and black holes, is incredibly rare.
