A team of researchers, including UvA physicists and astronomers, has studied gamma rays caused by the Sagittarius Dwarf, a small neighbouring galaxy of our Milky Way. They showed that all the observed gamma radiation can be explained by millisecond pulsars, and can therefore not be interpreted as a smoking gun signature for the presence of dark matter. The results were published in Nature Astronomy this week.

The center of our galaxy is blowing a pair of colossal bubbles ...

A research team led by a physicist at the University of California, Riverside, has demonstrated a new magnetized state in a monolayer of tungsten ditelluride, or WTe2, a new quantum material. Called a magnetized or ferromagnetic quantum spin Hall insulator, this material of one-atom thickness has an insulating interior but a conducting edge, which has important implications for controlling electron flow in nanodevices.

In a typical conductor, electrical current flows evenly everywhere. Insulators, on the other hand, do not readily conduct electricity. Ordinarily, monolayer WTe2 is a special insulator with a conducting edge; magnetizing it bestows upon it more unusual properties.

“We stacked monolayer WTe2 with an insulating ferromagnet of several atomic layer thickness—of Cr2Ge2...

Japanese astronomers report the detection of a new polar ring galaxy using the data obtained with the Subaru Telescope as part of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). The discovery was detailed in a paper published August 26 on the arXiv pre-print server.

The so-called polar ring galaxies (PRGs) are systems composed of an S0-like galaxy and a polar ring, which remain separate for billions of years. In general, these outer polar rings, composed of gas and stars, are aligned roughly in a perpendicular orientation with respect to the major axis of the central host galaxy.

However, although more than 400 PRG candidates have been discovered to date, only dozens of them have been...