Gamma-ray bursts are the brightest surges in the cosmos, discharging intense gamma rays for quick periods of time. These bursts are categorized as either short or long, with long gamma-ray bursts being produced by the death of huge stars. Gamma-ray bursts launch not just gamma rays, but also radio waves, optical light, and X-rays. When the performance of transforming surge energy to released energy is high, the total energy of the surge can be figured out by summing up all the produced energy. When the conversion effectiveness is uncertain or low, measuring only the produced energy is not enough to determine the overall explosion energy.
An artists impression of the gamma-ray burst GRB191221B. Credit: Urata et al./ Yu-Sin Huang/MITOS Science CO., LTD
. Gamma-ray bursts are the brightest surges in the cosmos, producing extreme gamma rays for short durations of time. These bursts are categorized as either short or long, with long gamma-ray bursts being produced by the death of huge stars. Why they supply surprise ideas about the advancement of the universe.
Gamma-ray bursts launch not only gamma rays, but likewise radio waves, optical light, and X-rays. When the performance of converting surge energy to produced energy is high, the overall energy of the explosion can be determined by summing up all the emitted energy. Nevertheless, when the conversion efficiency is low or unsure, determining only the released energy is not enough to calculate the overall surge energy.
Now, a team of astrophysicists has prospered in measuring a gamma-ray bursts surprise energy by utilizing light polarization. The team was led by Dr. Yuji Urata from the National Central University in Taiwan and MITOS Science CO., LTD, and Professor Kenji Toma from Tohoku Universitys Frontier Research Institute for Interdisciplinary Sciences (FRIS).
Information of their findings were recently published in the journal Nature Astronomy.
When an electro-magnetic wave is polarized, it implies that the oscillation of that wave flows in one direction. While light produced from stars is not polarized, the reflection of that light is. Many everyday products such as sunglasses and light guards make use of polarization to shut out the glare of lights taking a trip in a consistent direction.
Measuring the degree of polarization is referred to as polarimetry. In astrophysical observations, determining a celestial items polarimetry is not as simple as determining its brightness. It offers valuable info on the physical conditions of items.
The team looked at a gamma-ray burst that took place on December 21, 2019 (GRB191221B). Using the Very Large Telescope of the European Southern Observatory and Atacama Large Millimeter/submillimeter Array– a few of the worlds most innovative optical and radio telescopes– they calculated the polarimetry of fast-fading emissions from GRB191221B. They then effectively measured the optical and radio polarizations simultaneously, finding the radio polarization degree to be significantly lower than the optical one.
” This difference in polarization at the 2 wavelengths reveals in-depth physical conditions of the gamma-ray bursts emission area,” stated Toma. “In particular, it allowed us to measure the formerly unmeasurable concealed energy.”.
When accounting for the concealed energy, the team revealed that the total energy was about 3.5 times larger than previous quotes.
With the explosion energy representing the gravitational energy of the progenitor star, being able to determine this figure has essential implications for determining stars masses.
” Knowing the measurements of the progenitor stars true masses will help in understanding the evolutionary history of the universe,” included Toma. “The first stars in the universe could be found if we can identify their long gamma-ray bursts.”.
Recommendation: “Simultaneous radio and optical polarimetry of GRB 191221B afterglow” by Yuji Urata, Kenji Toma, Stefano Covino, Klaas Wiersema, Kuiyun Huang, Jiro Shimoda, Asuka Kuwata, Sota Nagao, Keiichi Asada, Hiroshi Nagai, Satoko Takahashi, Chao-En Chung, Glen Petitpas, Kazutaka Yamaoka, Luca Izzo, Johan Fynbo, Antonio de Ugarte Postigo, Maryam Arabsalmani, and Makoto Tashiro, 8 December 2022, Nature Astronomy.DOI: 10.1038/ s41550-022-01832-7.