On 9 January, the journal Nature published the discovery of a black hole of a million solar masses in Henize 2-10, a dwarf galaxy whose size is about 30 times smaller than the diameter of the Milky Way. This result suggests that the supermassive black hole formation precedes the formation of galaxies, pointing to a possible solution to a problem of the "chicken and egg" of concern to astronomers for decades.
A dwarf galaxy ...
Located about 30 million light-years from Earth, Henize 2-10 is a small irregular galaxy that has always puzzled astronomers. The galaxy is populated by large superclusters of young massive stars, indicating a highly active star formation, but the causes of this rampant activity were unknown.
With a size of only about 3,000 light-years, this dwarf galaxy has a projected area that is about 1,000 times lower than the main plane of the Milky Way. The mass of Henize 2-10 is similar to that of the Large Magellanic Cloud, this is about a tenth of that of our galaxy. However, the rate of star formation in Henize 2-10 is 10 times higher than that of the Large Magellanic Cloud.
... and a supermassive black hole
For his doctoral thesis, the Amy Reines young researcher at the University of Virginia, made observations of Henize 2-10 with several telescopes for an understanding as complete as possible of this mysterious galaxy. With Hubble, obtained a detailed image in the optical stellar population. Large interferometer with an image obtained VLA radio waves showed an intense emission from the central region (areas colored in yellow in the picture that heads this article.) Finally, with the Chandra space telescope noted that the same central region also appears very bright in X-rays Other intense X-ray sources, supernovae or active binary stars appear in blue in the header image.
The intense radiation of radio waves and X rays from the galactic core can only originate from the extremely energetic phenomena (accretion and ejection of jets at high speeds) that occur near a black hole. Therefore, these emissions prove the presence of a black hole of a million solar masses. This hole is so similar to those found in other much larger galaxies: the Milky Way has one of about 3 to 4 million solar masses. The supermassive black hole Henize 2-10 could have a large influence amazing fueling of star formation observed in the galaxy.
The presence of a supermassive black hole at the heart of most (if not all) large galaxies in our environment is well established by observation. In the local Universe, the masses of black holes are directly related to the masses of their host galaxies (the ratio of the mass of the hole in the galaxy is constant), a relationship that is not observed in our galaxy dwarf Henize 2-10.
Does chicken or the egg?
The association of supermassive black holes with large galaxies suggests that both objects evolve together. But this partnership immediately raises the question of what was first formed, if the black hole or the galaxy. For years it has implicitly admitted that the galaxy is formed first and the black hole results from the gravitational contraction of its central regions. Recently, however, has emerged the idea that a single black hole, in the initial stages of the evolution of the universe, could bring matters to be supermassive (perhaps as a result of the merger of smaller holes) and then build a galaxy around yours. We are therefore faced with a dilemma of the type "What came first, the chicken or the egg?".
A study conducted a few years ago showed that black holes of very young galaxies (observed at great distances, corresponding to early times of evolution of the Universe) are comparatively more massive than the galaxies in the local universe evolved. This study therefore seems to indicate that black holes are formed before the galaxies that surround end.
According to Amy Reines and collaborators, Henize 2-10 could be similar to these early galaxies. A black hole has been able to form without the presence of a large galaxy, this suggests that the hole formation precedes the formation of galaxies. However
this persuasive suggestion, based only on observation of a galaxy, in no way be taken as a demonstration. You need to continue to observe the relationship between galaxies and their holes in different types of galaxies (possibly in objects that represent different stages of evolution.) Particularly informative is the detailed observation of very distant galaxies and young people including the mysterious quasars. Also interesting
- The galaxy Henize 2-10 is named as the object number 10 of the second of the catalogs compiled by Karl Henize (1926-1993) in the 1950's. Karl Henize can be considered the prototype of the science astronauts. Besides being an excellent observer who worked in several astronomical observatories U.S., South Africa and Australia, Henize, while NASA astronaut was part of the crew of Apollo 15, the Skylab 2, 3 and 4 of the Spacelab-2 and the space shuttle Challenger. In 1974, he received the NASA Medal for outstanding scientific work.
- Henize 2-10 does not even have the large central cluster of stars that is present in almost all galaxies, which astronomers call the "galactic bulge."
- The results of Reiner and colleagues were published last January 9 in the online version of the prestigious journal Nature.
A dwarf galaxy ...
Located about 30 million light-years from Earth, Henize 2-10 is a small irregular galaxy that has always puzzled astronomers. The galaxy is populated by large superclusters of young massive stars, indicating a highly active star formation, but the causes of this rampant activity were unknown.
With a size of only about 3,000 light-years, this dwarf galaxy has a projected area that is about 1,000 times lower than the main plane of the Milky Way. The mass of Henize 2-10 is similar to that of the Large Magellanic Cloud, this is about a tenth of that of our galaxy. However, the rate of star formation in Henize 2-10 is 10 times higher than that of the Large Magellanic Cloud.
... and a supermassive black hole
For his doctoral thesis, the Amy Reines young researcher at the University of Virginia, made observations of Henize 2-10 with several telescopes for an understanding as complete as possible of this mysterious galaxy. With Hubble, obtained a detailed image in the optical stellar population. Large interferometer with an image obtained VLA radio waves showed an intense emission from the central region (areas colored in yellow in the picture that heads this article.) Finally, with the Chandra space telescope noted that the same central region also appears very bright in X-rays Other intense X-ray sources, supernovae or active binary stars appear in blue in the header image.
The intense radiation of radio waves and X rays from the galactic core can only originate from the extremely energetic phenomena (accretion and ejection of jets at high speeds) that occur near a black hole. Therefore, these emissions prove the presence of a black hole of a million solar masses. This hole is so similar to those found in other much larger galaxies: the Milky Way has one of about 3 to 4 million solar masses. The supermassive black hole Henize 2-10 could have a large influence amazing fueling of star formation observed in the galaxy.
The presence of a supermassive black hole at the heart of most (if not all) large galaxies in our environment is well established by observation. In the local Universe, the masses of black holes are directly related to the masses of their host galaxies (the ratio of the mass of the hole in the galaxy is constant), a relationship that is not observed in our galaxy dwarf Henize 2-10.
Does chicken or the egg?
The association of supermassive black holes with large galaxies suggests that both objects evolve together. But this partnership immediately raises the question of what was first formed, if the black hole or the galaxy. For years it has implicitly admitted that the galaxy is formed first and the black hole results from the gravitational contraction of its central regions. Recently, however, has emerged the idea that a single black hole, in the initial stages of the evolution of the universe, could bring matters to be supermassive (perhaps as a result of the merger of smaller holes) and then build a galaxy around yours. We are therefore faced with a dilemma of the type "What came first, the chicken or the egg?".
A study conducted a few years ago showed that black holes of very young galaxies (observed at great distances, corresponding to early times of evolution of the Universe) are comparatively more massive than the galaxies in the local universe evolved. This study therefore seems to indicate that black holes are formed before the galaxies that surround end.
According to Amy Reines and collaborators, Henize 2-10 could be similar to these early galaxies. A black hole has been able to form without the presence of a large galaxy, this suggests that the hole formation precedes the formation of galaxies. However
this persuasive suggestion, based only on observation of a galaxy, in no way be taken as a demonstration. You need to continue to observe the relationship between galaxies and their holes in different types of galaxies (possibly in objects that represent different stages of evolution.) Particularly informative is the detailed observation of very distant galaxies and young people including the mysterious quasars. Also interesting
- The galaxy Henize 2-10 is named as the object number 10 of the second of the catalogs compiled by Karl Henize (1926-1993) in the 1950's. Karl Henize can be considered the prototype of the science astronauts. Besides being an excellent observer who worked in several astronomical observatories U.S., South Africa and Australia, Henize, while NASA astronaut was part of the crew of Apollo 15, the Skylab 2, 3 and 4 of the Spacelab-2 and the space shuttle Challenger. In 1974, he received the NASA Medal for outstanding scientific work.
- Henize 2-10 does not even have the large central cluster of stars that is present in almost all galaxies, which astronomers call the "galactic bulge."
- The results of Reiner and colleagues were published last January 9 in the online version of the prestigious journal Nature.
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