对早期星系的新认识

The early galaxies¹ of the universe were very different from today's galaxies. Using new detailed² studies carried out with the ESO Very Large Telescope and the Hubble Space Telescope, researchers, including members from the Niels Bohr Institute, have studied an early galaxy³ in unprecedented⁴ detail and determined⁵ a number of important properties such as size, mass, content of elements and have determined how quickly the galaxy forms new stars. The results are published in the scientific journal Monthly Notices of the Royal Astronomical⁶ Society.   "Galaxies are deeply fascinating objects. The seeds of galaxies are quantum fluctuations⁷ in the very early universe and thus, understanding of galaxies links the largest scales in the universe with the smallest. It is only within galaxies that gas can become cold and dense⁸ enough to form stars and galaxies are therefore the cradles of starsbirths," explains Johan Fynbo, professor at the Dark Cosmology Centre at the Niels Bohr Institute at the University of Copenhagen.   Early in the universe, galaxies were formed from large clouds of gas and dark matter. Gas is the universe's raw material for the formation of stars. Inside galaxies the gas can cool down from the many thousands of degrees it has outside galaxies. When gas is cooled it becomes very dense. Finally, the gas is so compact that it collapses⁹ into a ball of gas where the gravitational compresion heats up the matter, creating a glowing ball of gas -- a star is born.