All posts tagged: binary black holes

The Universe is creating black holes in many different ways

The Universe is creating black holes in many different ways

Published by Jenni Sidey

When black holes collide, they do not all seem to follow the same cosmic script. A sweeping new analysis of the latest gravitational-wave catalog suggests the universe is producing merging black hole pairs through several distinct channels, not one. Some of those systems appear to come from ordinary stellar evolution, while others carry signs of stranger histories, including black holes that may already be the remnants of earlier mergers. The study draws on GWTC-5.0, the newest release from the LIGO-Virgo-KAGRA Collaboration, which includes data through the second part of the fourth observing run. In the population analysis, researchers examined 267 compact binary merger candidates, up from 161 in the previous catalog update. Of those, 259 were classified as binary black hole candidates for black-hole-only population studies. That expanding sample is changing the field’s focus. Instead of treating each signal as a one-off curiosity, researchers can now look for patterns across the population. This newest version of the “Masses in the Stellar Graveyard” plot compares the numbers and masses of black holes and neutron stars discovered …

Astronomers discover three distinct groups of merging black holes

Astronomers discover three distinct groups of merging black holes

Published by Jenni Sidey

Black hole collisions do not appear to come from one simple cosmic recipe. After studying more than 150 mergers detected through gravitational waves, astronomers say the growing catalog points instead to three distinct groups of merging black holes. Each group seems to carry its own signature in mass, spin, and how often the mergers happened across cosmic time. Taken together, the pattern suggests that these violent collisions are being built in more than one kind of environment. Their analysis focuses on the fourth gravitational-wave transient catalog from the LIGO-Virgo-KAGRA Collaboration, known as GWTC-4. That catalog includes more than 150 detected black hole mergers, enough for researchers to stop treating these events as a single blended population and start asking whether different families are hiding inside the data. Artist’s impression of a pair of black holes merging, involving one with unusual spin. (CREDIT: Carl Knox, OzGrav, Swinburne University of Technology) Not one family, but three One clue came from the masses. When the researchers looked across the full sample, they did not see a smooth spread. …