NASA has a long tradition of unexpected discoveries, and the space program’s TESS mission is no different. The SMU astrophysicist and her team discovered a particularly bright gamma-ray burst using a NASA telescope designed to find exoplanets – those that occur outside our solar system – especially those that could be able to support life.
This is the first time that a gamma-ray burst has been detected in this way.
Gamma-ray bursts are the brightest explosions in the universe, usually associated with the collapse of a massive star and the birth of a black hole. They can produce as much radioactive energy as the sun will emit during its 10 billion years of existence.
Krista Lynne Smith, assistant professor of physics at Southern Methodist University, and her team confirmed that the explosion – called GRB 191016A – occurred on October 16 and also determined its location and duration. A study on the discovery was published in The astrophysical journal.
“Our results prove that this TESS telescope is useful not only for finding new planets, but also for high-energy astrophysics,” said Smith, who specializes in using satellites like TESS (Transiting Exoplanet Survey Satellite). to study supermassive black holes and the gases that surround them. them. Such studies shed light on the behavior of deeply distorted space-time matter around black holes and the processes by which black holes emit powerful jets into their host galaxies.
Smith calculated that GRB 191016A had a maximum magnitude of 15.1, meaning it was 10,000 times fainter than the faintest stars we can see with the naked eye.
It might sound pretty gloomy, but the weakness is related to how far away the burst occurred. Galaxy light from GRB 191016A is estimated to have traveled 11.7 billion years before becoming visible in the TESS telescope.
Most gamma-ray bursts are weaker – closer to 160,000 times weaker than fainter stars.
The burst reached its maximum brightness between 1000 and 2600 seconds, then gradually faded until it fell below the ability of the TESS to detect it approximately 7000 seconds after its initial firing.
This gamma-ray burst was first detected by a NASA satellite called Swift-BAT, which was built to find these bursts. But since GRB 191016A occurred too close to the moon, the Swift-BAT was unable to do the necessary follow-up, it would normally know more until hours later.
NASA’s TESS was looking at this same part of the sky. It was pure luck, as TESS turns to a new band from heaven every month.
While the exoplanet researchers on an Earth base for TESS could tell right away that a gamma-ray burst had occurred, it would take them months to get data from the TESS satellite. But as they focused on the new planets, these researchers asked if other scientists at a TESS conference in Sydney, Australia, wanted to dig further into the explosion.
Smith was one of the few specialists in high-energy astrophysics at the time and quickly volunteered.
“The TESS satellite has a lot of potential for high energy applications, and it was too good an example to pass up,” she said. High-energy astrophysics studies the behavior of matter and energy in extreme environments, including regions around black holes, powerful relativistic jets, and explosions like gamma-ray bursts.
TESS is an optical telescope that collects light curves on everything in its field of view, every half hour. Light curves are a graph of the light intensity of an object or celestial region over time. Smith analyzed three of these light curves to be able to determine the brightness of the burst.
She also used data from ground observatories and the Swift gamma satellite to determine the distance of the burst and other qualities about it.
“Because the burst reached its peak brightness later and had a peak brightness that was higher than most bursts, it allowed the TESS telescope to make multiple observations before the burst disappeared below the limit. telescope detection, ”Smith said. “We provided the only spatial optical tracking of this exceptional explosion.