Image Credit: LIGO/Caltech/MIT/R. Hurt (IPAC)

In August of 2019, the LIGO-Virgo gravitational-wave network witnessed the merger of a black hole with 23 times the mass of our sun and a mystery object 2.6 times the mass of the sun. Scientists do not know if the mystery object was a neutron star or black hole, but either way it set a record as being either the heaviest known neutron star or the lightest known black hole.

There was strong CIERA involvement in this work. The paper was led by Director Vicky Kalogera. Also on the paper team was Marie Curie Postdoctoral Fellow Mario Spera, who led the discussion of the astrophysical implications. Graduate student Michael Zevin helped put together a first draft. Graduate student Chase Kimball calculated the merger rates (one of the most important pieces of information for interpreting the results); he is now the go-to person in the LIGO-Virgo Collaboration for these calculations, having led the work for multiple papers. Board of Visitors Research Assistant Professor Christopher Berry served as the lead of the Editorial Board for this paper.

Congratulations, everyone!

Learn More

• Northwestern News story, “LIGO-Virgo Finds Mystery Astronomical Object in Mass Gap“
• LIGO News Release, “LIGO-Virgo Finds Mystery Object in ‘Mass Gap’“
• The paper: GW190814: Gravitational Waves from the Coalescence of a 23 Solar Mass Black Hole with a 2.6 Solar Mass Compact Object
• The science summary: THE CURIOUS CASE OF GW190814: THE COALESCENCE OF A STELLAR-MASS BLACK HOLE AND A MYSTERY COMPACT OBJECT
• Interactive visualization by Frank Elavsky and Aaron Geller: Masses in the Stellar Graveyard
• Blog post by Christopher Berry: GW190814—The mystery of a 2.6 solar mass compact object
• Vimeo visualization by Alex Andrix: GW190814 Artistic Interpretation

Media Mentions of Northwestern/CIERA

• New York Times, “A Black Hole’s Lunch Provides a Treat for Astronomers” by Dennie Overbye

• CNN, “Gravitational waves reveal merger between black hole and mystery ‘mass gap’ object” by Ashley Strickland

• Fox News, “‘Mystery object’ spotted by astronomers changes talk of black holes, neutron stars” by James Rogers
• Scientific American, “Mystery Object Blurs Line between Neutron Stars and Black Holes” by Charlie Wood
• Smithsonian, “Distant Black Hole Collides With a Mysterious Object” by Alex Fox
• Inverse, “Is it a neutron star or black hole? Astronomers are confused by this mysterious object“
• International Business Times, “Black Hole’s Merger With Mysterious Object Stuns Scientists” by Athena Chan
• Science Magazine, “Gravitational waves reveal lightest black hole ever observed” by Adrian Cho
• France 24, “‘Mystery object’ in space may be smallest black hole“
• National Geographic, “Mysterious cosmic object swallowed by black hole baffles astronomers” by Nadia Drake
• ScienceNews, “LIGO and Virgo detected a collision between a black hole and a mystery object” by Maria Temming
• The Independent, “ASTRONOMERS SEE ‘MYSTERY OBJECT’ IN SPACE THAT COULD SOLVE BLACK HOLE PUZZLE” by Andrew Griffin
• Gizmodo, “A Black Hole Collided With Something That Shouldn’t Exist” by George Dvorsky
• Space.com, “Scientists just found the biggest neutron star (or smallest black hole) yet in a strange cosmic collision” by Meghan Bartels
• Tech Times, “Space Mysteries: Astronomers Discover Space Secrets that Could Solve Pluto, Black Hole Puzzle” by Tiziana Celine
• Futurism, “Astronomers May Have Discovered First-Ever ‘Black Neutron Star’” by Victor Tangermann
• Astronomy Magazine Online, “How astronomers learned to ‘listen’ to gravitational waves” by Caitlyn Buongiorno