The object believed to be a “star in the Milky Way” turned out to be the brightest quasar in history! | sorae universe portal website

「Quasar“At its center is a massive black hole (supermassive black hole), which shines so brightly that it can be observed even from more than 10 billion light-years away. Nearly a million quasars have been discovered so far, but only a small number of stars have been discovered.” Pseudomonas is very bright.

A research team led by Christian Wolff from the Australian National University said:J0529-4351“It's a quasar, and…The brightest quasar ever observed, about 500 trillion times brighter than the Sun and 200 times brighter than a typical quasar.I discovered that it is. J0529-4351 isIn the Astronomical Catalog, it is incorrectly classified as “99.98%, a star in the Milky Way”.Therefore, Wolf and his colleagues believe that there are many other very bright quasars that have already been observed but have not yet been observed.

■ Very bright quasars are difficult to find

Among the various celestial bodies in the universe,Quasar” Wow. At its center is a supermassive black hole, which is thought to be emitting energy because it absorbs large amounts of matter. It is trillions of times brighter than the Sun and thousands of times brighter than a typical galaxy. Quasars are often found in the distant universe, but seeing the distant universe It's the same view as the ancient universe, so quasars are objects that exist in the young universe.For this reason, quasars are thought to represent the early form of galaxies.

Astronomers have discovered about a million quasars since they were first identified in 1963. However, most of them have not been discovered by pointing a telescope at each one of them. In current astronomy, the common method is to find the celestial body you are looking for through a huge amount of observational data obtained by observing a wide area of ​​the night sky. Since there are as many celestial objects as there are stars in the observation data, the celestial objects are automatically classified using machine learning.

Although this method is useful for organizing vast catalogs of astronomical objects, it also has its problems. The machine learning that is the basis of the classification is trained based on the general characteristics of the celestial body that is the source of the classification. For this reason, if a celestial body shows very extreme characteristics, it can be difficult to identify the correct type and end up being labeled incorrectly. Although such errors are generally a small number, they can be an obstacle to finding objects with extreme properties.

■The object believed to be a “star in the Milky Way” turned out to be the brightest quasar in history!

The research team led by Wolfe et al.J0529-4351We conducted research focusing on the celestial body called “”. This celestial body is listed in the astronomical catalog “Gaia DR3” created using observational data from the “Gaia” space telescope launched by the European Space Agency (ESA), but in the catalog it is written “99.98% probability that it is a star in the Milky Way Galaxy“She was flagged.

However, looking at the spectroscopic data for J0529-4351, Wolff and his colleagues believed that it was not a star, but rather a quasar with a strong redshift. It was so special that Wolf and others wrote in their paper: “An astronomer familiar with Gaia's spectrum would be able to tell it is a quasar at a glance.” As a result of observations using the 2.3-meter telescope installed at Siding Spring Observatory (Coonabarabran, Australia), J0529-4351 is located about 23.8 billion light-years from Earth, about 12.2 billion years from now. We have confirmed that it is a quasar that existed in the previous era (redshift z = 3.962).(※). In addition, additional observational data from the Very Large Telescope (VLT) (Paranal Observatory, Chile) revealed the precise nature of J0529-4351 as a quasar.

*…This distance is the “transmission distance” value, taking into account that the space in which light travels has expanded due to the expansion of the universe. On the other hand, the simple multiplication of the time the light travels is called the “light travel distance” (or optical path distance).

J0529-4351 is an unusually bright object even as a quasar. Its brightness is 2×10 to 41 watts (20 watts positive),It is about 500 trillion times brighter than the Sun, about 40,000 times brighter than the Milky Way, and about 200 times brighter than a typical quasar.it will be. This is the brightest quasar known. It cannot be overcome that the automatic classification of Gaia is incorrect, as it is too bright to be recognized as a very distant object. Similar errors have occurred for several decades, and although the object was seen in a post-survey (SSS) record created in 1980, the oldest record, it has been overlooked until now.

This brightening is thought to be caused by the activity of the supermassive black hole J0529-4351, which heats the accretion disk, a disk of matter being created around it. Accretion disk J0529-4351 is thought to be about 7 light-years across, making it the largest accretion disk known. The supermassive black hole at its center is said to have a mass of about 17 billion times the mass of the Sun, which places it at the top of the black hole mass classification. In order to explain this brightness, the source of energy isWe breathe in a substance roughly equivalent to the mass of one sun every day.It is considered. It also has the highest amount of material (accretion rate) of any known quasar.

■Could there be other unusually bright quasars?

From this study, J0529-4351 holds the title of “brightest quasar in the history of observation,” but it may only hold the top spot for a short period of time. That's because, based on this discovery, along with J0529-4351,Many quasars may be dormant, misclassified because they are unusually bright.It's from. There are many comet hunting observation catalogs that record a large number of celestial objects. These catalogs
If we search for exoobjects like J0529-4351, we may find many bright quasars.

J0529-4351 has already been listed in the Astronomical Catalog of Data, and since it has unusual properties even when seen with the human eye, research has begun to confirm that it is a quasar. When this research is referred to in the future, we may realize that it was not just the discovery of a particularly bright quasar, but that it led to the discovery of many bright quasars.

source

• Christian Wolff, et al. “Daily accretion of solar mass by a black hole with a mass of 17 billion solar masses.” (natural astronomy)
• Christian Wolff, et al. “Brightest and fastest growing: Astronomers identify record-breaking quasar”. (ESO)

Written by Riri Aya