Light coming from a galaxy in the distance can be greatly bent by another galaxy in front of it.This phenomenon is called the "gravitational lens effect" and rarely occurs, usually only one galaxy in the background is affected by the galaxy in the foreground.It is no wonder in theory that multiple background galaxies are subject to the lens effect, but they have not been discovered in practice.
International research teams such as the University of Tokyo Graduate School of Science and the National Astronomical Observatory of Japan have reported that two distant galaxies are simultaneously affected by the gravitational lens effect from data taken by Hyper Supreme Cam (HSC), an ultra-wide-field primary focus camera of the Subaru Telescope. I found an extremely rare celestial body.It happened when the lecturer, Yoshiyuki Tanaka, a specially appointed assistant professor at the National Astronomical Observatory of Japan, was examining the images of the students and HSC at the time of the "School of Subaru" held by the National Astronomical Observatory of Japan Hawaii in September 2. It is said that it was discovered in.
A closer look at this object reveals that in addition to multiple points, there are two galaxies, a reddish arc and a bluish ring, and the galaxy that causes the gravitational lens in the center bends the light of the two objects. Has arrived.In other words, it suggests that there are two background galaxies that have been affected by the gravitational lens effect.The research team named it the "Eye of Horus" because the shape of this galaxy resembles the eye of God, known as the symbol of ancient Egypt.
We also knew that the distance to the central lens galaxy, which causes the gravitational lensing effect, was 70 billion light-years, but this time, the research team observed the distance between the two background galaxies with the Magellan telescope in Chile, South America. It was also revealed that they are at distances of 2 billion light-years and 90 billion light-years.
The Subaru Telescope is currently implementing a large-scale project "Strategic Frame Program" to observe a wide area of the sky with HSC, and the "Eye of Horus" was found based on the data obtained from this observation.The program is ongoing, and it is believed that if multiple gravitational lens objects are discovered from future data, it will be possible to explore the basic physics of the galaxy and the process by which the universe has expanded.
The results of this research were published in the Astrophysical Journal Letters of the Astronomical Society of America.
* The icon image is an enlarged image of only the "Eye of Horus".Quoted from National Astronomical Observatory of Japan
