A large Magellan cloud star throwing stars in the Milky Way could have a super-large black hole

Hypervelocity Stars (HVSS) was first theorized to exist in the late 1980s. In 2005, the first discovery was confirmed. HVSS travels much faster than regular stars and sometimes exceeds galaxy escape speed. Astronomers estimate that the Milky Way contains about 1,000 HVS, and new research shows that some of these are derived from the large Magellan Cloud (LMC), a satellite galaxy of the Milky Way. It’s been done.

Does the LMC have a super-heavy style black hole (SMBH) that drains some HVSS into the Milky Way?

Most stars in the Milky Way travel at about 100 km/s, while HVSS travels at about 1,000 km/s quickly. Established thinking supported by existing evidence states that HVS comes from galactic centers. Astronomers believe it comes from a binary star system that is too close to SGR. a*, Milky Way smbh.

In this scenario, one of the binary stars is captured by a black hole, and the other is ejected as an HVS. This is called the Hills mechanism. In fact, some of the original evidence supporting the existence of SGR. a* was based on a fast star in the center of the galaxy by the Hills mechanism.

A new study submitted to the Astrophysical Journal shows that an astounding number of Milky Way HVS comes from LMC, not from Galactic Center. The title is “Hypervelocity Stars trace ultra-high Massive black holes into large Magellan clouds.” The lead author is Harvard University alumni Jiwon Han, Harvard University and the Smithsonian Center for Astrophysics, which studies galactic archaeology, available on the ARXIV preprint server.

In 2006, researchers published the findings of HVSS in the Milky Way. This study detected 21 HVS, a bound B type main sequence star, at halos outside the Milky Way. Their properties were consistent with stars discharged from the galactic center by Hills mechanism. In this new study, astronomers revisited these stars. They had some help that were not available in 2006: the Gaia spaceship of the ESA.

Gaia is our star measuring superhero. Located at Sun Earth L2 Point, it measures 2 billion objects, mainly stars, and tracks position and speed. Han and his colleagues revisited 21 HVS using the appropriate moves Gaia provided. Gaia is a mission that has made great progress in understanding the Milky Way and is back.

“We see that half of the unbound HVS discovered by the HVS investigation have returned to LMC rather than Galactic Center,” Han and his co-authors wrote.

It motivated them to dig deeper. The researchers have built a model based on simulated stars emitted by the SMBH of LMC. “The predicted spatial and kinematic distributions of simulated HVS are very similar to the observed distribution,” the authors write.

Is there another underlying cause of HSV? Dynamic gravitational interactions are also possible because supernova explosions can eject stars. According to the authors, they cannot explain them. “We see that the birth rate and clustering of LMC HVS cannot be explained by supernova rampage and dynamic ejection scenarios that do not include SMBH,” the author explains.

One important evidence in favour of black holes in LMC is the excess density. This area, known as the Leo-excess density, is the area that heads towards the Leo-constellation, which has a higher star density than the surrounding area. Han and his collaborators say their models also create this same excess. SMBH, which has a solar mass of about 600,000 people in its LMC, throws stars into the Milky Way, some of which are HVSS, and some of which are present in excess density.

Their model shows that almost all stars with LEO excess density came from the LMC and its SMBH. To better understand that, they dug into how the hill mechanism works.

“The main components of the hill mechanism are: (1) mass of LMC, (2) binary star mass, (3) binary separation before tide breakdown, (4) around binary orbitals around SMBH Distances of the author writes. These are inputs to the hill mechanism, with the output being the ejection probability and velocity of the individual stars.

In the case of the emitted stars, researchers merged the orbit 400 million years ago to see where it would go. “We will ultimately “observe” the population of stars obtained from the current galactic rest frame and apply a selection function to match the observational constraints of the HVS survey,” the authors write.

The implications of this study may be extensive. The current idea states that all large galaxies contain SMBH, but not small galaxies. There is some evidence that small galaxies can embrace them, but in dwarf galaxies like LMC, for example, it may not be large enough to qualify as an actual SMBHS, depending on where the cutoff is. It has sex. Furthermore, they may not be actively accumulated, making them more difficult to detect in dwarf galaxies.

This research changes things.

The presence of black holes indicates that it does not generate HVS only. The movement of the galaxy also contributes. Future research on HVS should consider galactic motion.

This study also has implications for understanding galaxy growth and evolution. If astrophysicists lack black holes in small galaxies, that means that the theory of galaxy evolution is likely to lack the consequential data.

More studies of HVSS consider these results. GAIA data may help you find more HVSS in future data releases. That means more data points, what scientists are always looking for. That data allows researchers to build more detailed models and develop more stringent theories about HVSS and how they are produced.