The onset of star formation 250 million years after the Big Bang

Article

关键词: HUBBLE FRONTIER FIELDS;    LY-ALPHA;    NONPARAMETRIC INVERSION;    MAGNIFICATION MAPS;    GALAXY POPULATION;    FORMING GALAXY;    DUST;    REIONIZATION;    EMISSION;    CONSTRAINTS;   

DOI  :  10.1038/s41586-018-0117-z

来源: SCIE

【 摘 要 】

A fundamental quest of modern astronomy is to locate the earliest galaxies and study how they influenced the intergalactic medium a few hundred million years after the Big Bang(1-3). The abundance of star-forming galaxies is known to decline(4,5) from redshifts of about 6 to 10, but a key question is the extent of star formation at even earlier times, corresponding to the period when the first galaxies might have emerged. Here we report spectroscopic observations of MACS1149-JD1(6), a gravitationally lensed galaxy observed when the Universe was less than four per cent of its present age. We detect an emission line of doubly ionized oxygen at a redshift of 9.1096 +/- 0.0006, with an uncertainty of one standard deviation. This precisely determined redshift indicates that the red rest-frame optical colour arises from a dominant stellar component that formed about 250 million years after the Big Bang, corresponding to a redshift of about 15. Our results indicate that it may be possible to detect such early episodes of star formation in similar galaxies with future telescopes.

【 授权许可】

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