It seems that a “rogue black hole” is wandering around our galaxy

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“Rogue black hole” is a synonym for “rogue black hole” or “nomadic black hole”, which means that Black hole In question it does not have a host galaxy. In early 2022, scientists have already discovered what appeared to be a stray black hole drifting through our galaxy Milky Way.

According to ScienceAlertThis information can be confirmed by another team of specialists who conducted Investigation separate and independent of the first. The results of this new team led by astronomers Casey L And the Jessica Low from UC Berkeley, however differ in some points The first study Posted in February 2022 and edited by Kailash Sahu: the estimated mass of the object this time indicates that it could also be a neutron star from a black hole.

Either way, this second study highlights a new ability of a phenomenon that is known but, until then, has not made it possible to locate dark, compact objects: microgravity lenses.

Astronomers use it to measure the deformation of distant stars by an object’s gravitational field as it passes in front of them. “It is the first stray black hole or neutron star to be discovered using a micro-gravitational lensJessica Lowe explains. Using it, we can examine and weigh these single and compressed objects. We have opened a new window on these dark objects, which cannot be seen otherwise.»

Black hole or neutron star?

In theory, the black holes They are the result of the collapse of massive stars, which weigh more than 30 times the mass of the Sun and have a relatively short life. So far it is believed that there are between 10 million and a billion black holes drifting through our galaxy. Only, the property of such an object is that it does not produce any light (unless the material meets it and thus generates x-rays). So it is difficult to detect.

The difficulty is not impossible, and this is where the famous note microgravity lenses. Thus, on June 2, 2011, two separate surveys recorded an event named “OB110462” that culminated on July 20. Exceptionally tall and luminous, it has attracted the attention of scientists. The team led by Kailash Sahu concluded by thanking Hubble telescopethat it was a black hole 7.1 times the mass of the Sun and located more than 5,153 light-years away.

The latest analysis of the rogue black hole led by Lamm and Lu also used data collected by Hubble, but says it would be a slightly smaller object: between 1.6 and 4.4 times the mass of the Sun. This is what puts them on the path of a file neutron star.

Neutron stars are caused by the collapse of massive stars that weigh between 8 and 30 times the mass of the Sun (therefore they are lighter than massive stars that end up in black holes). thanks to “degeneration pressure”, these stars do not completely collapse into black holes. Thus neutron stars have a lower mass: about 2.4 times the mass of the Sun … which, according to the new study, puts OB110462 outside the category of black holes.

Thus, estimates vary, but this does not mean that nothing can be learned from OB110462, on the contrary. Even Casey Lam said: “Either way, the object remains the first dark stellar remnant discovered to wander the galaxy unaccompanied by another star.”