Hubble finds a rare explosion in an unexpected place in the cosmos

2023-10-06 10:58:00

A NASA Hubble Space Telescope image of the Luminous Fast Blue Optical Transient (LFBOT) designated AT 2023fhn – NASA, ESA, STSCI, ASHLEY CHRIMES

MADRID, 6 Oct. (EUROPA PRESS) –

A very rare and strange burst of light extraordinarily bright in the universe became even stranger after observations by the Hubble Space Telescope.

The phenomenon, called Luminous Fast Blue Optical Transient (LFBOT for its acronym in English), appeared on the scene where it was not expected to be found, far from any host galaxy. Only Hubble could determine its location. And the results are leaving astronomers even more confused. For starters, they don’t know what LFBOTs are. The Hubble results suggest that They know even less by ruling out some possible theories.

LFBOTs are among the brightest visible light events known in the universe and fire unexpectedly like camera flashes. Only a few have been found since the first discovery in 2018, an event located about 200 million light years away that was nicknamed ‘the Cow’. Currently, LFBOTs are detected once a year.

After its initial detection, the latest LFBOT was observed by multiple telescopes across the electromagnetic spectrum, from X-rays to radio waves. Designated AT2023fhn and nicknamed ‘the Finch’, the transient event showed all the telltale characteristics of an LFBOT. It shone brightly in blue light and evolved rapidly, reaching maximum brightness and fading again in a matter of days, unlike supernovae, which takes weeks or months to attenuate.

But unlike any other LFBOT seen before, Hubble discovered that ‘the Finch’ is located between two neighboring galaxies: about 50,000 light years from a nearby spiral galaxy and about 15,000 light years from a smaller galaxy.

“The Hubble observations were really crucial. They made us realize that this was unusual compared to other similar observations, because without the Hubble data we wouldn’t have known,” Ashley Chrimes, lead author of the finding reporting, said in a statement. about the discovery in Monthly Notices of the Royal Astronomical Society (MNRAS).

The image above taken by Hubble shows three galaxies against the velvety black background of space. The largest is the white and blue spiral-shaped galaxy in the center of the image. Two smaller galaxies are whitish blobs to the left. A curious white spot near the top of the image is the bright glow of some unknown object that exploded, but it is not associated with any of the galaxies.

LFBOTs could be the result of stars torn apart by an intermediate mass black hole (between 100 and 1,000 solar masses). The high resolution and infrared sensitivity of NASA’s James Webb Space Telescope could eventually be used to discover that ‘the Finch’ exploded inside a globular star cluster in the outer halo of one of two neighboring galaxies. A globular star cluster is the most likely place to find an intermediate-mass black hole.

To explain the unusual location of ‘the Pinzón’, researchers are considering the possibility that is the result of a collision of two neutron stars, which travel very far from their host galaxy, and have been spiraling toward each other for billions of years. These collisions produce a kilonova, an explosion 1,000 times more powerful than a standard supernova. However, a highly speculative theory is that if one of the neutron stars is highly magnetized (a magnetar), it could greatly amplify the power of the explosion to even 100 times the brightness of a normal supernova.