(ORDO NEWS) — Galaxies come in all shapes and sizes, but the basic constituents seem to be fairly constant.
There is usually a large black hole in the center, a bunch of stars and gas, and a lot of dark matter, which helps to glue it all together.
Although dark matter is, well, dark, stars, gas, and a rotating core of heated material stand out with the radiant beauty of a city at night.
However, one newly discovered dwarf galaxy, located just 94 million light-years away, defies expectations. It is called FAST J0139+4328 and does not emit optical light. In fact, it emits almost no light at all.
FAST J0139+4328 appears to be a so-called dark galaxy. Apart from a small number of stars, the galaxy appears to be composed almost entirely of dark matter.
“These findings provide evidence that FAST J0139+4328 is an isolated dark dwarf galaxy,” writes a team of astronomers led by Jin-Long Xu of the Chinese Academy of Sciences in Beijing.
“This is the first time that an isolated dark galaxy has been discovered in a neighboring universe.”
Dark matter is currently the leading explanation for the strange discrepancy between the amount of normal, or baryonic, matter observed in the universe the corners of the universe and the force of gravity needed to hold it together.
Simply put, there is not enough baryonic matter to explain all of gravity. The galaxies are spinning so fast that they should fly apart unless something else binds them together.
Whatever is responsible for this additional gravity remains unclear. It doesn’t seem to interact with ordinary matter in any way except through gravity; nor does it emit any form of radiation that we can currently detect.
We simply cannot see the source of this extra mass. However, reserving space for some unknown material goes a long way towards solving the problems we are seeing.
However, the theory of dark matter is also not perfect. One problem is the discrepancy between modeling the distribution of dark matter in the universe and the number of dwarf galaxies we see out there orbiting larger galaxies.
There are far fewer dwarf galaxies than the simulations suggested. This is known as the dwarf galaxy problem.
We may simply not be able to detect certain types of dwarf galaxies, for example, those with very few stars that are mostly gas and dark matter.
Finding enough of these galaxies would help solve the whole problem of the shortage of dwarf galaxies.
Several candidates for dark galaxies have been identified, but they are very close to other structures, so they are difficult to distinguish from debris clumps torn free. stronger gravitational forces.
The ideal candidate for a dark galaxy should drift by itself, isolated in space where its identity cannot be mistaken.
To search for such a galaxy, Xu and his colleagues used the 500m Aperture Spherical Radio Telescope (FAST) in China.
They used the telescope during breaks in its observing schedule as a “filler” to search for radio emission from large clouds of neutral atomic hydrogen (HI) in intergalactic space, looking for features consistent with the galaxy.
And they were successful: the radio waves emitted by the HI cloud 94 million light-years away corresponded to the rotating disk of the galaxy without the optical emission expected from it.
Subsequent observations in the infrared and ultraviolet ranges revealed a weak scattering of stars.
Together, these data allowed the researchers to determine the properties of the galaxy, which they named FAST J0139+4328.
According to the team’s calculations, the galaxy has an upper limit of 690,000 solar mass stars and contains 83 million solar masses of HI. The total baryonic mass of the galaxy is about 110 million solar masses.
However, this is just a drop in the ocean of the total mass of the galaxy.
The team was able to calculate FAST J0139+4328’s rotational speed and, from that, its total mass, which was 5.1 billion solar masses. This means that the galaxy is about 98 percent dark matter.
Other scientists are expected to attempt to confirm the object’s nature. In this case, things may turn out differently, as happened with a galaxy called Dragonfly 44.
In 2016, it was discovered that the galaxy is 99.99% dark matter. However, four years later, astronomers determined that Dragonfly 44 was not all that anomalous.
But if it is confirmed as a dark galaxy, FAST J0139+4328 will tell us something very interesting about the Universe. around us.
“For the first time, a gas-rich, isolated dark galaxy has been discovered in a neighboring universe,” the researchers write.
“Also, the galaxy is thought to be formed from gas that cools and turns into stars at the center of the halo.
FAST J0139+4328 has a rotating disk of gas and is dominated by dark matter, but it has no stars, which means that this dark The galaxy may be in the earliest stage of galaxy formation.”
—
Online:
Contact us: [email protected]
Our Standards, Terms of Use: Standard Terms And Conditions.