supermassive black hole tagged posts

In just the right conditions, the destruction of a star in a black hole’s gravitational tide should produce an unusual flash of light. Credit: Chandra/Harvard

When astronomers and astrophysicists observe flashes of light in the dark sky, they assume they have seen a supernova. Possibly a star has burnt up its supply of nuclear fuel and collapsed, throwing off its outer layers into space; or maybe a dense white dwarf siphoned off material from a companion star until it exploded from excess weight. But a flash of light observed on June 14, 2015 did not fit any of the usual models.

For one thing, the intensity of the light was double that of the brightest supernova recorded up to that point. So astrophysicists were already asking what process could have caused it...

An artist’s depiction of a rapidly spinning supermassive black hole surrounded the rotating leftovers of a star that was ripped apart by the tidal forces of the black hole. Credit: ESO, ESA/Hubble, M. Kornmesser

Astronomers illuminate the role rapidly spinning black holes play in tidal disruption events. Back in 2015 when astronomers discovered an intense flare in a distant galaxy, they considered it the brightest supernova ever observed. Now, UC Santa Barbara astrophysicists and a group of international colleagues offer an entirely different interpretation based on new astronomical observation data from the Las Cumbres Observatory (LCO), a global robotic telescope network, and the Hubble Space Telescope.

The new information indicates that the event, called ASASSN-15lh, is actually a tidal...

Credit: Harvard-Smithsonian Center for Astrophysics

The center of the Milky Way galaxy is currently a quiet place where a supermassive black hole slumbers, only occasionally slurping small sips of hydrogen gas. But it wasn’t always this way. A new study shows that 6 million years ago, when the first human ancestors known as hominins walked the Earth, our galaxy’s core blazed forth furiously. The evidence for this active phase came from a search for the galaxy’s missing mass.

Measurements show that the Milky Way galaxy weighs about 1-2 trillion times as much as our Sun. About 5/6 of that is in the form of dark matter. The remaining 1/6 of our galaxy’s heft, or 150-300 billion solar masses, is normal matter...