RECORD . To measure the distance of GN-z11, astronomers have pushed the Hubble Space Telescope to its limits and it is difficult to learn more about it before the James Webb Telescope is operational. With a hundred times greater sensitivity, it will deliver new details about this galaxy that formed while only 3% had universe of its present age. A record. Previously the oldest galaxy was identified EGS-zs8-7, 200 million years his senior.
A surprising discovery
GN-z11 was already known to astronomers but with new spectral measurements, made with the wide-field camera WFC3 Hubble, they could reassess its age. “ We made a big step back in time, beyond what we thought to be able to do with Hubble ” enthuses Pascal Oesch from Yale University and lead author of a study to be published in the Astrophysical Journal . This very young galaxy was observed by Hubble because it is especially light: it processes about 24 solar masses of gas and dust into new stars each year, a star formation rate 20 times that of the Milky Way currently. Below chronological tree of the Universe with the position of this new galaxy.
Mystery . Compared to other galaxies, GN-z11 is not really impressive. It is 25 times smaller than the Milky Way and weighs just 1 billion solar masses against hundreds of thousands to ours. But it is a “monster” cosmic given his training period. In fact, its presence is a surprise to astronomers: “ The discovery of GN-z11 was a big surprise for us, our previous work suggests that these bright galaxies should not be so early in the Universe” says Marijn Franx of Leiden University in the Netherlands. A colleague, Ivo Labbe says that “ The formation of Gn-ZE11 remains somewhat mysterious and proves that our knowledge of the universe is still very limited.”
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