Summary

An international team including astronomers at the National Astronomical Observatory of Japan (NAOJ) discovered an interaction between astrophysical jets and intracluster magnetic fields. This result provides a new window to explore the hidden side of the magnetized Universe.
Astronomers used MeerKAT telescope, the state-of-the-art radio interferometer located in South Africa, to unveil the origin of unusual jets in the merging galaxy cluster Abell 3376.

In April 2019, scientists released the first image of a black hole in the galaxy M87 using the Event Horizon Telescope (EHT). However, that remarkable achievement was just the beginning of the science story to be told.

Data from 19 observatories are being released that promise to give unparalleled insight into this black hole and the system it powers, and to improve tests of Einstein’s General Theory of Relativity.

Astronomers have played a game of guess-the-numbers with cosmological implications. Working from a mock catalog of galaxies prepared by a Japanese team, two American teams correctly guessed the cosmological parameters used to generate the catalog to within 1% accuracy. This gives us confidence that their methods will be able to determine the correct parameters of the real Universe when applied to observational data.

Astronomers have tested a method for reconstructing the state of the early Universe by applying it to 4000 simulated universes using the ATERUI II supercomputer at the National Astronomical Observatory of Japan (NAOJ). They found that together with new observations the method can set better constraints on inflation, one of the most enigmatic events in the history of the Universe. The method can shorten the observation time required to distinguish between various inflation theories.

These results appeared as Masato Shirasaki et. al. “Constraining Primordial Non-Gaussianity with Post-reconstructed Galaxy Bispectrum in Redshift Space,” in Physical Review D on January 4, 2021.

(February 16, 2021)

New simulations carried out in part on the ATERUI II supercomputer in Japan have found that the reason ions exist at higher temperatures than electrons in space plasma is because they are better able to absorb energy from compressive turbulent fluctuations in the plasma. These finding have important implications for understanding observations of various astronomical objects such as the images of the accretion disk and shadow of the M87 supermassive black hole captured by the Event Horizon Telescope.

Researchers from Kobe University and the National Institute of Technology, Oshima College discovered that ancient tectonic troughs on Ganymede are concentrically distributed across almost the entire surface. This global distribution indicates that these troughs may actually be part of one giant crater covering Ganymede. Based on a computer simulation, it is speculated that this giant crater could have resulted from the impact of an asteroid with a radius of 150 km. If so, this is the largest impact structure identified in the Solar System so far.

Computer simulations conducted by astrophysicists at Tohoku University in Japan, have revealed a new theory for the origin of supermassive black holes. In this theory, the precursors of supermassive black holes grow by swallowing up not only interstellar gas, but also smaller stars as well. This helps to explain the large number of supermassive black holes observed today.

Numerical simulations showed that the temperature gradient in the disk of gas around a young gas giant planet could play a critical role in the development of a satellite system dominated by a single large moon, similar to Titan around Saturn. Researchers found that dust in the circumplanetary disk can create a “safety zone,” which keeps the moon from falling into the planet as the system evolves.

The origin of how the Universe created its voids and filaments can now be studied within seconds after researchers developed an artificial intelligence tool called Dark Emulator.

"I have seen the dark universe yawning,
Where the black planets roll without aim;
Where they roll in their horror unheeding, without knowledge or lustre or name."
--H.P. Lovecraft, Nemesis

Theoreticians in two different fields defied the common knowledge that planets orbit stars like the Sun. They proposed the possibility of thousands of planets around a supermassive black hole.