wandering. Lonely. isolated. These are the definitions of stellar black holes detected in the Milky Way.
Drift, to be exact, 5,000 light-years from Earth, floating in the spiral arms of Carina-Sagittarius at 160,000 kilometers per hour. And, like him, about 100 million nomadic objects of this type — without any star companions — may be “traveling” through our galaxy.
The discovery of the first isolated black hole is the result of a six-year analysis of data captured by the Hubble Space Telescope by two research teams, according to NASA.
One of the groups was led by Kailash Sahu of the Space Telescope Science Institute in Baltimore, with participation from Brazil.
Another group was led by Casey Lam of the University of California. Both use gravitational microlensing technology.
The technique involves observing the magnification of the brightness of a background star (called a source) due to the passage of an object (called a lens) between the observer and the source. The lens deforms the space-time around it, and the light from the light source is then deflected, increasing its brightness for the observer.
“In this case, the black hole passing between the observer and the background star acts like a lens that, in addition to increasing the brightness of the source over 200+ days (the time period in which the event was monitored), also changes its position. Astrometry”, explains astrophysicist Leonardo Almeida.
“I remember this microlens well. It became so bright that it could be observed with a small telescope at the Pico dos Dias Observatory in Brazopolis, Minas Gerais. That same year, we already suspected that The curves of the microlenses, said Almeida, a professor at the Universidad Federal de Rio Grande do Norte:
While the Berkeley team knew it could still be a neutron star, the unique fingerprint in the star’s dimming could eliminate other potential gravitational lensing candidates, according to a NASA statement.
The research led by Sahu shows that as the lens passes in front of the star, the deflection caused by the lens points to an object seven times the mass of the sun.
“The deduced mass and the lack of detection of glare from the lens hint at a possible lensing object, a black hole of stellar origin. The mass of the black hole is a good confirmation of the stellar evolution model of an isolated object. However, this black hole was not seen before it became our Before a lone nomad in the Milky Way, it could also be part of a binary system, so it is impossible to determine what the history of this object is. However, it is certain that this event not only proves again that Albert Ein Stein’s theory is correct, but it also opens an important window for us to begin to better understand the composition of these objects and our galaxy,” said Leonardo Almeida.
stellar black hole
According to NASA, stellar-mass black holes have been known since the early 1970s, but all their mass measurements—until now—have been made in binary star systems. The companion star’s gas falls into the black hole and is heated so high that it emits X-rays.