Thursday , October 28 2021

Cosmological rules: how giant cosmic distances were measured by studying gamma brightness



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The measurement of large cosmic distances is aided by several “rules” – phenomena known for features such as light. Then, by comparing the known properties or known properties of some functions with the observed properties, we can determine how far the phenomenon is from us.

© ESO / L. Espaloia (CC BY 4.0) |  commons.wikimedia.org
© ESO / L. Espaloia (CC BY 4.0) | commons.wikimedia.org

One of the best rules for determining the distances of distant galaxies is type I supernovae, whose maximum brightness is almost always the same. Rulers can also be converted to gamma-ray flares, but there is a greater variety of their properties and types, which makes it difficult to find the right relationship for measuring distance. In a new study, it was conducted by examining the largest sets of gamma rays that occurred at known distances.

The brightness of the gamma rays also emits radiation from other sections, and initially the X-rays have a plateau phase – they have remained virtually unchanged for some time. For all gamma flashes, there is a relationship between three parameters: the maximum light of gamma radiation, the light of X-rays in the plateau phase, and the duration of the plateau phase.

The relation can be represented as a plane in a three-dimensional space composed of these parameters. However, not all individual brightness is in this plane – their X-ray plains are sometimes ten times different from the predicted relationship.

Examining the sample in detail, the researchers found three subpopulations, the members of which are very far from the plane, making them more suitable for dominance of cosmic distance. The best set is short gamma glows that occur with kilowatt explosions. One such event occurred in August 2017 and was also the first fusion of neutron stars trapped between gravitational waves. All of these flashes are smaller than what the overall relationship predicts in the X-ray range, but using them alone can predict the actual X-ray plain light of the flash to be better than 1%.

This finding may help to better understand the nature of different types of gamma flashes.

The results of the study are “arXiv”.

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