A galaxy rapidly forming stars 700 million years after the Big Bang at redshift 7.51. Academic Article uri icon

abstract

  • Of several dozen galaxies observed spectroscopically that are candidates for having a redshift (z) in excess of seven, only five have had their redshifts confirmed via Lyman emission, at z = 7.008, 7.045, 7.109, 7.213 and 7.215 (refs 1-4). The small fraction of confirmed galaxies may indicate that the neutral fraction in the intergalactic medium rises quickly at z>6.5, given that Lyman is resonantly scattered by neutral gas. The small samples and limited depth of previous observations, however, makes these conclusions tentative. Here we report a deep near-infrared spectroscopic survey of 43 photometrically-selected galaxies with z>6.5. We detect a near-infrared emission line from only a single galaxy, confirming that some process is making Lyman difficult to detect. The detected emission line at a wavelength of 1.0343 micrometres is likely to be Lyman emission, placing this galaxy at a redshift z = 7.51, an epoch 700 million years after the Big Bang. This galaxy's colours are consistent with significant metal content, implying that galaxies become enriched rapidly. We calculate a surprisingly high star-formation rate of about 330 solar masses per year, which is more than a factor of 100 greater than that seen in the Milky Way. Such a galaxy is unexpected in a survey of our size, suggesting that the early Universe may harbour a larger number of intense sites of star formation than expected.

published proceedings

  • Nature

altmetric score

  • 678.026

author list (cited authors)

  • Finkelstein, S. L., Papovich, C., Dickinson, M., Song, M., Tilvi, V., Koekemoer, A. M., ... Willner, S. P.

citation count

  • 188

complete list of authors

  • Finkelstein, SL||Papovich, C||Dickinson, M||Song, M||Tilvi, V||Koekemoer, AM||Finkelstein, KD||Mobasher, B||Ferguson, HC||Giavalisco, M||Reddy, N||Ashby, MLN||Dekel, A||Fazio, GG||Fontana, A||Grogin, NA||Huang, J-S||Kocevski, D||Rafelski, M||Weiner, BJ||Willner, SP

publication date

  • October 2013

published in