A galaxy rapidly forming stars 700 million years after the Big Bang at redshift 7.51
Nature 502, 7472 (2013). doi:10.1038/nature12657
Authors: S. L. Finkelstein, C. Papovich, M. Dickinson, M. Song, V. Tilvi, A. M. Koekemoer, K. D. Finkelstein, B. Mobasher, H. C. Ferguson, M. Giavalisco, N. Reddy, M. L. N. Ashby, A. Dekel, G. G. Fazio, A. Fontana, N. A. Grogin, J.-S. Huang, D. Kocevski, M. Rafelski, B. J. Weiner & S. P. Willner
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 α emission, at z = 7.008, 7.045, 7.109, 7.213 and 7.215 (refs 1, 2, 3, 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 α 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 α difficult to detect. The detected emission line at a wavelength of 1.0343 micrometres is likely to be Lyman α 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.
Radio astronomy: Finger on the pulsar
Nature 502, 7472 (2013). doi:10.1038/502439a
Author: Bernie Fanaroff
Bernie Fanaroff probes a study on how radio telescopes have opened up our understanding of the Universe.
Astrophysics: Recipe for regularity
Nature 502, 7472 (2013). doi:10.1038/502453a
Authors: Ellen Zweibel
A detailed astrophysical model has been laid out that not only reproduces the far-infrared–radio correlation for galaxies that are actively forming stars, but also predicts how the correlation is modified at high redshift.
Astronomy: New distance record for galaxies
Nature 502, 7472 (2013). doi:10.1038/502459a
Authors: Dominik A. Riechers
Spectroscopic measurements of 43 candidates for distant galaxies have confirmed one to be the most remote galaxy securely identified to date — and it forms stars more than 100 times faster than the Milky Way. See Letter p.524
Final word is near on dark-matter signal
Nature 502, 7472 (2013). http://www.nature.com/doifinder/10.1038/502421a
Author: Eugenie Samuel Reich
An influential US experiment prepares to release its first results.
A new image of the sunward plunging Comet ISON taken by NASA's
Hubble Space Telescope on October 9, 2013, suggests that the
comet is intact despite some predictions that the fragile icy
nucleus might disintegrate as the Sun warms it. The comet will
pass closest to the Sun on November 28.
On Thursday, October 17 at 4pm EDT there will be a live chat event with Hubble's comet scientists to discuss the new image and latest research findings on ISON. Visit: https://plus.google.com/events/c4te7qh2fo468ke9uou3e3rbr3s .
An international team of astronomers has found the most distant gravitational lens yet a galaxy that, as predicted by Albert Einstein's general theory of relativity, deflects and intensifies the light of an even more distant object. The discovery provides a rare opportunity to directly measure the mass of a distant galaxy. The observation also poses a mystery: lenses of this kind should be exceedingly rare. Given this and other recent finds, astronomers either have been phenomenally lucky or, more likely, they have underestimated substantially the number of small, very young galaxies in the early universe.