Astronomers observe a luminous fast blue optical transient (LFBOT) known as the Tasmanian devil, which has been flashing at peak brightness multiple times, months after the initial explosion.
Astronomers have been left perplexed by a recent observation of an explosion in space that has been flashing at peak brightness more than a dozen times, long after the initial event. This enigmatic phenomenon, known as a luminous fast blue optical transient (LFBOT), has raised new questions while potentially offering insights into the causes behind such explosions. LFBOTs, which have been observed across the Universe, have defied explanation thus far. This latest observation, named the Tasmanian devil, adds to the growing body of evidence surrounding these mysterious occurrences.
The Curious Case of Luminous Fast Blue Optical Transients (LFBOTs):
LFBOTs first caught the attention of astronomers with the discovery of the Cow, designated AT2018cow, in 2018. The Cow, located 200 million light years away from Earth, stood out due to its brightness, which was up to 100 times greater than that of a supernova. Unlike a supernova, which takes weeks to dim, the Cow’s brightness faded over a span of just a few days.
Since then, over half a dozen LFBOTs have been identified, including the Koala, the Camel, and the Finch, which was discovered earlier this year. However, the cause behind these explosions remains uncertain. The leading theories suggest that LFBOTs are either failed supernovae, intermediate-mass black holes consuming other stars, or the result of interactions with Wolf-Rayet stars, which are hot and bright.
The Tasmanian Devil Sheds Light on LFBOTs:
In a study published in Nature on November 15th, a team of astronomers led by Anna Ho from Cornell University in New York describes their observations of the Tasmanian devil, formally known as AT2022tsd. Located approximately 1 billion parsecs away, this LFBOT exhibited repeated flashes at its peak brightness, starting in December 2022. The researchers recorded a total of 14 flaring events, each lasting only minutes.
These unexpected flares, each as powerful as the original LFBOT, have astounded experts. Raffaella Margutti, an astrophysicist at the University of California, Berkeley, describes the observation as unprecedented and believes it raises numerous questions.
Unraveling the Mystery:
Anna Ho suggests that the flaring observed in the Tasmanian devil could support the theory of a failed supernova. According to this hypothesis, a massive star, about 20 times the mass of the Sun, runs out of fuel and collapses, leaving behind a dense neutron star or black hole within the remnants of the surrounding star. Ho proposes that the flashes may originate from either a neutron star or a black hole formed during the initial LFBOT event.
If the LFBOT’s central neutron star or black hole possesses powerful jets of energy emanating from its poles, these jets could explain the observed flaring. As the object rotates, the jets would project into space, and if they repeatedly align with Earth, they could produce the flashes of light witnessed from the Tasmanian devil.
Brian Metzger, an astrophysicist at Columbia University, finds the observation striking and believes it confirms previous conclusions that LFBOTs involve high-speed electrons being heated or accelerated in an outflow. Further observations could help determine the mass of the object, providing definitive insights into its origin. Ho explains that by measuring the speed at which the signal varies, astronomers can estimate the size of the object emitting the signal. A high-speed variation would suggest rapid rotation, indicating a lower mass.
Conclusion:
The repeated flaring of the Tasmanian devil LFBOT has shed new light on the mysterious nature of these explosions in space. While the exact cause remains elusive, the observation supports the theory of failed supernovae and the presence of neutron stars or black holes at the heart of LFBOTs. As astronomers eagerly await the completion of the Vera C. Rubin Observatory, which will conduct a wide survey of the universe, they hope to discover and study more of these objects soon after their initial explosion. This will be crucial in unraveling the mysteries surrounding LFBOTs and narrowing down their potential causes.
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