E03: Record Breaking Black Hole Collision

INTRODUCTION

• Black holes are essentially dead stars. There can be three kinds of BH; stellar black holes, intermediate-mass black holes, and supermassive black holes. You go up the mass axis via eating other stars or merging with other black holes.
• Black holes can be seen eating gas through observations of X-ray radiation. They can also be seen merging via gravitational wave detections.
• Laser Interferometry Gravitational-wave Observatory (LIGO) first saw a black hole collision/merger in September 2015. LIGO also won the Nobel Prize in Physics in the year 2017

DISCOVERY

• In Sept 2020, LIGO reported a BH merger of two very massive BH resulting in an IMBH of 142 times the mass of our sun. This is the most massive gravitational wave detection to date.
• The two inspiralling progenitor black holes had masses of about 85 and 66 solar masses and resulted in the formation of a black hole remnant of 142 solar masses and 6 solar masses of gravitational wave emission.
• The progenitor black holes are also very massive and are very hard to produce with current theories. One possibility is that these progenitors were results of BH mergers too. However, there is no way to detect that. 
• This discovery looked different than the previous signals seen. Earlier gravitational waves have been like “chirps” but this one was more of a “bang.” So, scientists have also been wondering about other sources that can produce GW. Such as a supernova in our Galaxy or a Cosmic String just created in the early ages of the universe. The chances are very small but still interesting.

MORE RESOURCES

• Press Release
• Published Paper
• YouTube Illustration
• Audio of the collision

Links to Science Outreach Material:

• McDonald Institute
• Royal Astronomical Society
• Astronomy on Tap

Special thanks to Colin Vendromin for the music also thanks to Zac Kenny for the logo!