We begin to discover wandering black holes whizzing through the Milky Way

That stars over 8 masses will not end with white dwarf but explodes supernovae SNII. Those with masses greater than 20/30 solar masses should not shed enough fabric in the explosion so thatcollapse gravity most often gives one neutron star, but rather a star-sized hole. The observed masses have between 5 and 15 solar masses. They signal themselves in The Milky Way due to the material they tear from a companion star and which forms one accretion disk where forces of viscous friction between currents of matter, spirals downwardstar compact, heat it to the point where it emits X-rays.

But according to astrophysicists theorists studying the birth of neutron stars and the black holes of the starsit may happen that the explosion is asymmetric and that the final compact body is consequently propelled as if it were one rocket. It is easy to calculate as shown byhe course in astrophysics from the famous William Pressthan just by its explosion in one binary system with a large mass loss, the laws of mechanics also imply that one neutron star or a newly formed star-black hole is thrown in high course velocitysometimes to the point that they are able to free themselves from the attraction of gravity The Milky Way.

Astrophysicists therefore believe that there must be a large population of solitary black star holes that roam or strike through our planet. Galaxy. The number of these objects can be estimated at approx 100 million but there are several uncertainties as to the models describing their birth, so in fact it is a little more accurate to say that this number is probably somewhere between 10 million and one billion. Vise versawould a determination of this number make it possible to sort these models from and also to have information about the stars and therefore chemical evolution of galaxies, because they are enriched with new heavy elements with each explosion of the type supernovae NS II.

But how do you detect these isolated black holes, since they do not accumulate matter and therefore do not indirectly generate radiation?

Astronomers may have discovered the first free-floating black hole in the Milky Way, thanks to a technique called a gravitational micro-lens. To get a fairly accurate French translation, click on the white rectangle at the bottom right. The English subtitles were then to appear. Then click on the nut to the right of the rectangle, then on “Subtitles” and finally on “Automatically translate”. Select “French”. © NASA’s Goddard Space Flight Center

A black hole that makes the stars shine

That general theory of relativity gives the answer. It predicts the field of gravity which may end up deflecting a light beam which would be sent from a point very close to the surface of the events in a black hole to the point that it falls in the direction of this black hole is also capable of deflecting the stars of the rays in front of which this object can be inserted for an observer to the point that the environment close to the black hole behaves like a gravitational lenswhich may temporarily increase brightness of the star in front of which the black hole passes.

Astrophysicists have therefore undertaken to chase events that manifest this phenomenon by gravitational microlensing with various instruments, and two teams have just announced, via a release in The Astrophysical Journal Letters and another in The Astrophysical Journalthat they had finally found a candidate for an isolated star-sized hole in the Milky Way.

The two teams were initially based on observation campaigns with photometric data, which on the one hand come fromOptical gravity lens experiment (OGLE) and on the other hand experience Microlensic observations in astrophysics (MOA). OGLE uses one telescope 1.3 meter telescope in Chile powered by the University of Warsaw, and MOA uses a 1.8 meter telescope in New Zealand powered by the University of Osaka. Since both microlens studies captured the same object, it is gate two names: MOA-2011-BLG-191 and OGLE-2011-BLG-0462, or in short OB110462.

The team led by Casey Lam and Jessica Lu byUC Berkeley estimated the star-shaped black hole behind the event to be between 2,280 and 6,260 light years towards the center of the Milky Way, in Carina-Sagittarius spiral arm of our galaxy. She also estimates that the mass of the invisible compact object is between 1.6 and 4.4 times the mass of Sun (the more massive the object, the stronger the lens effect so we can measure its mass). Astrophysicists are therefore cautious because it can be either a neutron star or a black hole.

But the members of the other team, led by Kailash Sahu from Space Telescope Science Institute in Baltimore (Maryland) based on the same data but also on observations from the Hubble Telescope, is more certain of its claims. For its members, the compact object is about 5,153 light-years away, and above all, it would have a mass of about 7.1 times the mass of the Sun. This time, the object is too heavy to be a neutron star according to the theory of these objects, and the most likely hypothesis is that it is actually a black hole and not a another exotic star that is still unknown.

Sahu’s team estimates that the isolated black hole moves through the galaxy at a staggering speed of 160,000 kilometers per hour, which is fast enough to travel from Earth to Earth. Moon in less than three hours.

This discovery allows astronomers statistically to estimate that the closest isolated black hole with stellar mass to Earth could be as close as 80 light-years away.

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