Measuring the Natal Kick of a Black Hole

For the first time in the history of space, scientists have captured the recoil velocity of a catastrophic collision into a newborn black hole. A remarkable step in the mysterious universe, this breakthrough will uncover new insights into black hole emergence and behaviour. With the discovery of ‘Natal Kick’, it will be a new revolution in astrophysics. Read the article further to get to know about the natal kick and how it is shaping the structures of the universe.

ALSO READ- Great Nicobar Island Project

What is Natal Kick?

Scientists observed a powerful collision and measured the speed and direction of the natal kick that leads to the formation of a newborn compact object in space.

Natal kick is an astrophysical phenomenon at the time of the merging of two black holes to form a newborn black hole. If the new black hole differs in size or spin, it is removed from its birthplace at high speed. The phenomenon emerged as a result of an unequal mass ratio and a spin difference. This creates a merger and collision imbalance, leading to expulsion of the new object.

Details on New Measurement-

• Scientists have for the first time measured a natal kick, which is a sudden recoil of two black holes that flings the newborn blackhole from its origin due to differences in mass, energy and spin.
• This discovery was first detected in April 2019 by LIGO and Virgo observatories and named GW490412.
• The lead scientist, Juan Caldron Bustillo, from the Galician Institute of High Energy Physics in Spain (GIHEP), with teammates from institutions associated with LIGO/Virgo, including Kaustav Chandra (a PhD researcher from Pennsylvania State University) and Samson H.W. Leong (Chinese University of Hong Kong).
• According to reports, one black hole has 29.7 times the sun’s mass and the other 8.4 times, which was merged; however, this imbalance pushed the new black hole away from its birthplace.
• The scientists have carefully interpreted the gravitational waves and calculated the velocity (speed and direction) of the collision.
• The movement of the cataclysmic collision was about 50 km per second, which is enough to fling it away from star clusters and travel freely in space.

How were the measurements carried out?

By balancing both theoretical concepts and practical implementations, scientists were able to determine the first natal kick. 

• In 2018, theoretically, researchers found a method to infer recoil from gravitational wave signals. With the help of this data, they were able to collect necessary information about the masses, spins and asymmetries of the merging black holes.
• A gravitational wave signal, GW490412, was found in 2019 that originated from the merger of two black holes having unequal mass ratios. This inequality caused the repulsion of a new black hole, and is hence called the natal kick, which means expelled out from its source.
• Researchers carried out an analysis from various Earth angles through gravitational waves to determine the velocity of the event. 
• All this information was collected to reconstruct the 3D model of the newly formed black hole.
• The measurement was possible with high-order codes, providing additional orientation details. The discovery has enabled scientists to not only determine the direction but also the speed of this event.

Importance of the Natal Kick-

The discovery of the natal kick will open new doors to the secrets of the universe and help in determining the movement of black holes. It is important as:

• Mapping and Structure: Detection of the natal kick using the gravitational waves technique will allow researchers to track the distribution of black holes and speculate on their importance in galaxy evolution. The revelation will assist in reconstructing the origin and evolution of black holes.
• Evolution and Growth: Natal kick propels newborn black holes from their host place, forcing them out of the star clusters. This prevents them from merging with other stars and turning into a massive black hole, explaining the theories behind why some galaxies have large black holes while others do not.
• Fostering Gravitational Wave Astronomy: With the measurement of the natal kick, the scientists will be able to examine the 3D motion and recoil of black holes through space. This will open new avenues for gravitational wave astronomy, combining the data with traditional light-based astronomy to throw a clear picture of cosmic events.
• Theoretical Knowledge of Supernova Physics and Asymmetric Collision: The research on natal kick will unveil the pathway to supernova explosion, a powerful explosion of a massive star that can light up the entire universe and an asymmetric collision that expels the newborn blackhole from its origin. It will clarify the science behind the phenomenon, mainly caused by inconsistent spins, differences in masses and energy clashes.  
• Advancing Future Space Research: The new findings will help in fostering the future research prospects and encouraging observations of black hole kicks, their role in galactic evolution and transforming neutron stars into cosmic giants.

Difference between Natal Kicks in Neutron Stars and Black Holes-

Cause of Natal Kick:

• In neutron stars, asymmetries in the supernova explosion, including uneven mass and neutrinos, are present. The collapse can be violent and illuminate the universe for some time.
• In black holes, natal kicks are received in two ways: (1) Direct Collapse, the collapse of a massive star with little asymmetry. (2) Fallback Supernova, black holes formed after a supernova that leaves a neutron star to collapse. The collision can be similar to a supernova explosion.

Natal Kick Velocities:

• The velocity of a neutron star can be in the range of 100-1000 km/s or more than that.
• Whereas, in black holes, the velocity is up to 50 km/seconds.

Observation Methods:

• The neutron star kicks are easier to measure and are observed as pulsars with detectable proper motion.
• It’s difficult to detect the kicks in black holes as they are dark in colour. According to research, the velocities can be estimated based on the position and motion of X-ray binaries.

Typical Mass Range:

• The solar mass range of a neutron star is 1.1-2.5.
• While the black holes have 5-30+ solar masses. 

Binary System Impact:

• The collision can disrupt the binary system and high-speed neutron stars as runaways.
• It may or may not disrupt binaries, but with lower velocity, binaries can survive.

ALSO READ- What is Nano Banana?

FAQs-