Hubble Space Telescope observes unexplained brightness in a distant galaxy

A few months ago, the Hubble Space Telescope and other scientific tools worldwide focused on an enormous burst of gamma rays originating far across the universe. The massive gamma-ray burst released more energy in half a second than our Sun will produce over its entire 10-billion-year lifetime. Over the eons, the light from that enormous burst traveled to Earth and was seen from Earth in May 2020.

The NASA's Neil Gehrels Swift Observatory first detected the burst. After it was detected, NASA used the Hubble Space Telescope to perform observations of the source. Other scientists worldwide viewed the phenomenon with instruments including the Very Large Array Radio Observatory, the W.M. Keck Observatory, and the Las Cumbres Observatory Global Telescope network. The goal was to study the explosions aftermath and the host galaxy.

Hubble's unique viewing position enabled it to be the first to discover that the near-infrared emission was ten times brighter than expected. The results challenged conventional theories of what happens in the aftermath of a short gamma-ray burst. Scientists believe there is a possibility the observations point to the birth of a massive, highly magnetized neutron star called a magnetar.

Without observations from Hubble, the gamma-ray burst would have appeared similar to many others. However, researchers investigating the phenomena say that the puzzle pieces of this gamma-ray burst don't fit together because the near-infrared emission was too bright. Intense gamma-ray bursts appear to come from jets of material moving extremely close to the speed of light. However, these jets of material don't contain a lot of mass; it's their speed that causes them to release tremendous amounts of energy across all wavelengths of light.

One unique aspect of this particular gamma-ray burst was that it was a rare instance where scientists could detect light across the entire electromagnetic spectrum. Scientists say that as more data comes in, they form a picture of the mechanism that produced the light observed from Earth. The team says they were forced to discard conventional thinking and realized a new phenomenon was occurring, forcing them to redetermine the physics behind extremely energetic explosions. Researchers believe that most gamma-ray bursts likely result in a black hole, but in this instance, two neutron stars that merged may have combined to form a magnetar.