For decades, astronomers have searched without much success for signs of a “missing link” black hole — a black hole with a mass intermediate between “stellar-mass” and “supermassive” black holes. The former have been observed scattered throughout the universe, while the latter are cosmic giants that occupy the centers of galaxies. But scientists have only seen evidence of a dozen or so intermediate-mass black holes.
Reports say Early this monthThe scientists Hubble Space Telescope Reveals best evidence yet of intermediate-mass black holes Omega Centauri, Remnants of a Devoured Galaxy milky wayAnd, well, it seems to be searching Intermediate-mass black hole It’s a lot like waiting for a bus in London: if you wait too long for one bus, two buses will come at the same time.
Another research team has found evidence of another medium-sized black hole, this time lurking near a supermassive black hole. Sagittarius A* (Sgr A*) It is located in the centre of the Milky Way galaxy, about 27,000 light years from Earth.
A research team led by Florian Peisker of the University of Cologne discovered the intermediate-mass black hole while studying the star cluster IRS 13, about 0.1 light-years away from Sagittarius A*.
Related: Over the past 25 years, black hole physicists have discovered the unimaginable.
“IRS 13 appears to be an essential component in the growth of the central black hole Sgr A*,” says Peisker, “This fascinating cluster has continued to astonish the scientific community since its discovery almost 20 years ago. It was originally thought to be an unusually massive star, but our high-resolution data have allowed us to see a component composition with an intermediate-mass black hole at its center.”
Exploring the lost spaces of the universe
Stellar-mass black holes, with masses between 5 and 100 times that of the Sun, Star Collapse They have a mass at least eight times that of a star, but supermassive black holes must have a different origin, since no stars are massive enough to collapse and leave behind debris. Millions or Billions It has many times the mass of the sun.
From this information, scientists theorized: Supermassive black hole Must be born Merger Chain An ever-growing collection of black holes. These cosmic giants are thought to grow by voraciously eating the material around them, including any unlucky stars that get too close and are shattered into pieces, becoming packed into these so-called “black holes.” “Tidal Disruption Event” or “TDE”.
This is because the population Black hole “seeds” The universe contains a vast mass gap between stellar mass and supermassive black holes, which are too large to have formed from collapsing stars but not yet reached the “supermassive state.” Finding these intermediate-mass black holes has been frustratingly difficult.
Like other black holes, intermediate-mass black holes are surrounded by a “surface” that traps light. Event HorizonThis boundary between the observable universe and what’s inside a black hole not only means that no signals can travel from inside the black hole to the wider universe, but it also makes it virtually impossible to “see” a black hole — unless it destroys stars with a luminous TDE, or eats the material around it, heating it up and making it glow brightly.
But because intermediate-mass black holes aren’t surrounded by an abundance of material to feed on, they can’t reach supermassive sizes, don’t radiate bright light into their surroundings, and are almost completely dark. That’s why scientists have to use clever techniques to detect intermediate-mass black holes that aren’t feeding. For example, they can observe the behavior of visible material around the black hole, such as stars, to see if the black hole is being affected in any way. The effects of gravity. If so, those effects could be caused by a nearby black hole.
While observing IRS 13, Peisker and his colleagues observed that the stars in this cluster at the center of the Milky Way galaxy move in regular patterns, which was surprising because the team had expected the stars to be aligned randomly.
There are two possible explanations for this observation. Sagittarius A*This suggests that the stars move in an orderly fashion, or that there is a large gravitational influence in the cluster that keeps it in order.
Using equipment such as Very Large Telescope (VLT), Atacama Large Millimeter/submillimeter Array (ALMA) And that Chandra X-ray Space TelescopeScientists have determined that IRS 13’s tidy, compact shape may be due to the presence of an intermediate-mass black hole located at its center.
This discovery is supported by x-rays the astronomers observed from the cluster, which show ionized gas rotating at speeds of hundreds of thousands of miles per hour. This hot, ionized gas may be swirling around the mouth of this newly discovered intermediate-mass black hole.
Not only does this provide astronomers with another link to the “lost” black hole, it may also solve the lingering mystery surrounding IRS 13. The cluster appeared to be much denser than other similar clusters in the galaxy, which would be natural if an intermediate-mass black hole were to exist.
The research team now plans to follow up this study by examining IRS 13. James Webb Space Telescope (JWST) And that Extremely Large Telescope (ELT) It is currently under construction on the summit of Cerro Almazones in the Atacama Desert in northern Chile.
The research team’s study was published on July 18th. Astrophysical Journal.
