synonymStarburst galaxy (Starburst galaxy) generally refers to starburst galaxy
Starburst galaxy(Starburst Galaxies)fixed starThe outbreak area formed is characterized byInfrared luminositySignificantly higher thanPhotometry。Ordinary galaxies such as the Milky Way also form stars, but the formation speed is very slow. In starburst galaxies, the formation of stars is very intense.If the starburst galaxy can remain stable, the cosmic gas that forms new stars inside it will consume very quickly.The famous starburst galaxies areursa majorM82 galaxy.Starburst galaxies are produced at a rapid speedNovaAt the same timeSupernovaBurst.
There is an unusual "super wind" outflow of gas in a star bearing galaxy, with a speed of thousands of kilometers per second.
Starburst galaxy
According to the US Space Network, astronomers recently observed that there was an unusual "super wind" outflow in a star forming galaxyGasIts speed can reach thousands of kilometers per second.
This starburst galaxy is called "NGC 4666". It is 80 million light years away from the Earth and is a hotbed for stars to be born.Due to the gravitational interaction between NGC 4666 galaxy and its neighboring galaxies, NGC 4666 galaxy has a large number of stars.New stars in the developing stage can be seen at the lower left of the figure.
European Southern ObservatoryAfter observing the image, astronomers fromqualityThe strong wind current of a star combines with the explosion of a supernova to form a strong airflow, called "super wind", which is released into space from the interior of the galaxy.
Jorg Dietrich, an astronomer at the University of Michigan, said, "The super wind originated in the bright central region of NGC 4666 galaxy and extends to tens of thousands of light years. The wind speed of this cosmic wind can reach thousands of kilometers per second. It is very difficult to directly observe the super wind, but this super wind can make the gas become dense and cool, which will facilitate observation.”
These cosmic gases are very hot, and mainly emit radiation in the form of X-ray, which cannot be directly observed under visible light.At present,ChileThe latest image of NGC 4666 was captured by the wide area imager of the MPG/ESO 2.2m diameter telescope at La Sila Astronomical Observatory, and revealed the existence of super wind.
The Mystery of Isolation
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Starburst galaxy
For a long time, astronomers have been wondering why a nearby small isolated galaxy can produce new stars faster than any neighboring galaxy?Now, NASA's Hubble Space Telescope has helped astronomers solve the mystery of NGC 1569, an isolated starburst galaxy.Hubble observations show that the distance of the galaxy is one and a half times that previously thought.
The increased distance makes the galaxy lie between a group of galaxies, which have about 10 members, and the center isSpiral galaxyIC 342。The gravitational action of galaxy cluster members may compress the gas in NGC 1569 and ignite the flame of star birth.
Alessandra Aloisi, from the Space Telescope Science Institute in Baltimore, Maryland and the European Space Agency, is the leader of the study. She said: "Now, the starburst activity seen in NGC 1569 is meaningful, because the galaxy may be interacting with other galaxies in the group. These interactions may provide fuel for star formation."
Far distance not only means that the intrinsic luminosity of a galaxy is brighter, but also means that it produces stars twice as fast as previously thought.The rate of star formation in this galaxy is more than 100 times higher than that in the Milky Way.Such a high star formation rate has been maintained for the past 100 million years.
NGC 1569, discovered by William Herschel in 1788, is the location of the three largest star clusters in our cosmic backyard.Each cluster contains more than one million stars.
Roeland van der Marel of the Space Telescope Science Institute, a member of the research team, said: "This is an example of large-scale star production activities that drive the evolution of galaxies in the distant youth universe. We can only carefully study starburst galaxies in the adjacent regions of the universe, where they are much rarer.Hubble's observations of our Milky Way's neighbors, including this work, are helping astronomers piece together the integrity of neighboring galaxiesimage。Just like NGC 1569, putting the puzzle in the right place can make the panorama more meaningful. "
Aloisi and her team actually discovered a new distance value by accident.They are using Hubble's advanced mapping camera to search for red giant stars (stars near the end of life) in NGC 1569Helium fusionAnd shine.These stars are darker than bright red giant stars without helium burning, but once they can be detected, they can be used to estimate the age of galaxies.
Aaron Grocholski of the Space Telescope Science Research Institute said: "We didn't find any obvious clues about them, so we estimated that the distance of this galaxy is farther than previously thought. We can only see the brightest red giant stars, but we can use them to calibrate the distance of the galaxy." Grocholski is the first author of the paper describing the results.Bright red giant stars are reliable in measuring distance“Standard candle”, because their brightness is the same.When astronomers know the true brightness of a star, they can calculate its distance from the earth.
Previous utilizationGround-based telescopeThe measured galaxy distance is unreliable, because the observation is the crowded core of the galaxy, and the single red giant cannot be distinguished.
The Hubble study looked at the chaotic core of the galaxy and the sparse periphery.Hubble's sharp advanced mapping camera has identified a single red giant star, which can accurately determine the distance of the galaxy.Astronomers measured the distance between galaxies at nearly 11 million light years, 4 million light years farther than the previous data.
Aloisi said: "This is an accidental discovery. The depth of Hubble observation is not enough to see the darkest red giant we want to find, because the distance of the galaxy is farther than we previously thought. But because we have captured all the bright red giant families, we can calculate the exact distance of NGC 1569 and solve the mystery of the extremely high star burst activity of the galaxy."
The members of the scientific research team carrying out NGC 1569 observation include Alessandra Aloisi and Marco Sirianni from STSCI and ESA, Aaron Grocholski from STSCI, Jennifer Mack and Roeland van der Marel, Luca Angeletti from INAF-OAB, Donatella Romano and Monica Tosi, and Francesca Annibali, Laura Greggio and Enrico Held from INAF-OAP.
The central region of starburst galaxy M82
The Hubble Space Telescope is an international cooperation project between NASA and the European Space Agency (ESA)Goddard Space Flight Center (GSFC, Greenbelt, MD).The Space Telescope Science Institute (STSCI) manages Hubble's scientific research operations.The agency is operated for NASA by the University Astronomical Research Consortium in Washington, D.C.
Suspicion
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Black holes from starburst galaxies?
The formation of a super large black hole requires huge mass, so it may be composed of many small black holesblack holeGathered together.From this perspective, some scientists have proposed that supermassive black holes are generated by starburst galaxies.
For a long time, astronomical observations have shown that disk shaped star forming bursts often occur where galaxies merge and interact.Recently, people believed that even if the two galaxies did not merge, the interaction between the galaxies close together could make the galaxies rotate unstably, leading to the gas gathering towards the core like a funnel, which ignited the starbursts around the core.
Starburst galaxies generate new stars at a rapid speed, and at the same time cause supernova explosions with a rapid momentum.Finally, a large number ofsunlightBlack holes of quality level.These black holes then gather the surrounding gas to become more massive black holes.Scientists speculate that these close black holes may merge with each other to form giant black holes.
Starburst galaxies have enough material to form supermassive black holes.But unfortunately, according to the current theoretical calculation, such a black hole merger mode is too slow. Even after 10 billion years, the gas mass gathered by black holes only accounts for a few percent of their own mass.
The most distant starburst galaxy
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HFLS3
An image of a starburst galaxy, which is very similar to the remote early starburst galaxy HFLS3 recently discovered[1]
In a new study, scientists found a primitive galaxy about 13 billion light years away from the Earth.The discovery of this galaxy is expected to break the original distance record of such galaxies and reveal the mystery about how and when some of the most massive "star manufacturing factories" operated in the early history of the universe.
With the help of the European Space Agency, which has the ability to observe in the infrared bandHerschel space telescopeA team of astronomers observed this distant starburst galaxy. The so-called starburst galaxy refers to a galaxy with a large number of stars forming.When this ancient galaxy existed, the universe was only 800 million years old, but now it is about 14 billion years old.
This galaxy, numbered HFLS3, is the most distant starburst galaxy ever discovered by writers.It is producing new stars at a very high rate, which is more than one billion years ahead of the earliest such phenomenon known to astronomers.
Dominik Riechers, an astronomer at Cornell University in Ithaca, New York, is the first author of this article published in Nature on April 17.He said: "This newly discovered galaxy is pushing the research in many fields of astronomy to the limit." He said: "It is not only the earliest similar case that we found, but also one of the galaxies with the highest star formation rate, even higher than the galaxy with a later formation time."
According to the current estimation data, the size of this galaxy is approximately close to that of the Milky Way. Astronomers were surprised to find that this galaxy is producing new stars at the rate of 2900 solar masses per year."This rate is 2000 times higher than that of our Milky Way," Richel said. "Considering that a large number of newborn stars in its interior emit intense light and heat radiation at the same time, it is almost close to the limit of the galaxy itself."
Long term strenuous activities
Although this galaxy is blocked by a large number of dust clouds and is far away, the galaxy HFLS3 appears extremely bright, emitting intense radiation in the infrared band, and its power is 30 trillion times that of the sun.This feature reminds astronomers that they must have found a super massive starburst galaxy, because only those galaxies with extremely active star birth activities can be so bright.
For Richel and his team, another surprise comes from spectroscopic analysis, whose results can reveal the chemical composition of the galaxy, showing that this galaxy has rich and diverse chemical composition, and its characteristics are similar to modern starburst galaxies.Since some heavy elements, such as carbon and iron, are believed to have formed in the ashes of the first generation of star explosions, astronomers once believed that these similar elements should be relatively scarce in the first billion years of the universe.
Richel said: "This shows that in the interior of galaxy HFLS3, such a violent star formation process has lasted for a long time, which is long enough to let the first batch of stars formed first die, destroy in the explosion and throw these heavy elements into the surrounding cosmos."
Galaxy swaddling
Until recently, astronomers believed that starburst galaxies, which are producing a lot of newborn starsHFLS3 galaxyIt was formed in a much later period.Richel said: "Previously, we believed that only in a later period, those stars with the largest mass in the universe could accumulate enough gas material to support the birth of a large number of stars.However, this discovery has proved that under some special environmental conditions, some galaxies can start the intense star birth process when the universe is only about 800 million years old, thus making the emergence of mature massive galaxies possible. "
National Radio ObservatoryChris Carilli, an astronomer fromElliptical galaxySome of the oldest stellar bodies observed in the.He said: "Now we know the reason for this phenomenon: because they were formed in a very early age. Such distant starburst galaxies may represent the formation of elliptical galaxies in the early violent history of the universe."
These most massive elliptical galaxies were recently discovered in the core of some large galaxy clusters.The galaxy HFLS3 is probably the early "embryo" of this kind of massive galaxy cluster we see today. Carrari said, "These observations and research work have pushed the era of the formation of massive galaxies forward to the age of the first ray of dawn in the universe."
