Object Discovered in Mass Gap Between Black Holes and Neutron Stars
takyon writes:
When the most massive stars die, they collapse under their own gravity and leave behind black holes; when stars that are a bit less massive than this die, they explode and leave behind dense, dead remnants of stars called neutron stars. For decades, astronomers have been puzzled by a gap in mass that lies between neutron stars and black holes: the heaviest known neutron star is no more than 2.5 times the mass of our sun, or 2.5 solar masses, and the lightest known black hole is about 5 solar masses. The question remained: Does anything lie in this so-called mass gap?
Now, in a new study from the National Science Foundation's Laser Interferometer Gravitational-Wave Observatory (LIGO) and the European Virgo detector, scientists have announced the discovery of an object of 2.6 solar masses, placing it firmly in the mass gap. The object was found on Aug. 14, 2019, as it merged with a black hole of 23 solar masses, generating a splash of gravitational waves detected back on Earth by LIGO and Virgo. A paper about the detection is available in The Astrophysical Journal Letters.
"We've been waiting decades to solve this mystery," said Vicky Kalogera, a professor at Northwestern University. "We don't know if this object is the heaviest known neutron star, or the lightest known black hole, but either way it breaks a record."
More details: The Curious Case of GW190814: The Coalescence of a Stellar-Mass Black Hole and a Mystery Compact Object
The lighter component of the GW190814 merger could have been an intermediate object such as a quark star or Q-star.
Also at BBC.
Journal References:
GW190814: Gravitational Waves from the Coalescence of a 23 M Black Hole with a 2.6 M Compact Object (open, DOI: 10.3847/2041-8213/ab960f) (DX)
GW190814: Gravitational Waves from the Coalescence of a 23 Solar Mass Black Hole with a 2.6 Solar Mass Compact Object - IOPscience, The Astrophysical Journal Letters (DOI: 10.3847/2041-8213/ab960f)
LIGO-P190814-v10: GW190814: Gravitational Waves from the Coalescence of a 23 Msun Black Hole with a 2.6 Msun Compact Object, (DOI: https://dcc.ligo.org/P190814/public)
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