Free-floating stars in the Milky Way's bulge

The path of a light beam is bent by the presence of mass, as explained by General Relativity. A massive body can therefore act like a lens—a so called "gravitational lens"—to distort the image of an object seen behind ...

How to weigh stars with gravitational lensing

Astronomy & Astrophysics publishes the predictions of the passages of foreground stars in front of background stars. A team of astronomers, using ultra-precise measurements from the Gaia satellite, have accurately forecast ...

Is dark matter made of primordial black holes?

Astronomers studying the motions of galaxies and the character of the cosmic microwave background radiation came to realize in the last century that most of the matter in the universe was not visible. About 84 percent of ...

Stars born in winds from supermassive black holes

Observations using ESO's Very Large Telescope have revealed stars forming within powerful outflows of material blasted out from supermassive black holes at the cores of galaxies. These are the first confirmed observations ...

Space telescopes pinpoint elusive brown dwarf

In a first-of-its-kind collaboration, NASA's Spitzer and Swift space telescopes joined forces to observe a microlensing event, when a distant star brightens due to the gravitational field of at least one foreground cosmic ...

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