A dusty, normal galaxy in the epoch of reionization
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A dusty, normal galaxy in the epoch of reionization. / Watson, Darach; Christensen, Lise; Knudsen, Kirsten Kraiberg; Richard, Johan; Gallazzi, Anna; Michałowski, Michał Jerzy.
In: Nature, Vol. 519, 27.02.2015, p. 327-330.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - A dusty, normal galaxy in the epoch of reionization
AU - Watson, Darach
AU - Christensen, Lise
AU - Knudsen, Kirsten Kraiberg
AU - Richard, Johan
AU - Gallazzi, Anna
AU - Michałowski, Michał Jerzy
N1 - Nature in press. 14 pages, 10 figures, including methods section
PY - 2015/2/27
Y1 - 2015/2/27
N2 - Candidates for the modest galaxies that formed most of the stars in the early universe, at redshifts $z > 7$, have been found in large numbers with extremely deep restframe-UV imaging. But it has proved difficult for existing spectrographs to characterise them in the UV. The detailed properties of these galaxies could be measured from dust and cool gas emission at far-infrared wavelengths if the galaxies have become sufficiently enriched in dust and metals. So far, however, the most distant UV-selected galaxy detected in dust emission is only at $z = 3.25$, and recent results have cast doubt on whether dust and molecules can be found in typical galaxies at this early epoch. Here we report thermal dust emission from an archetypal early universe star-forming galaxy, A1689-zD1. We detect its stellar continuum in spectroscopy and determine its redshift to be $z = 7.5\pm0.2$ from a spectroscopic detection of the Ly{\alpha} break. A1689-zD1 is representative of the star-forming population during reionisation, with a total star-formation rate of about 12M$_\odot$ yr$^{-1}$. The galaxy is highly evolved: it has a large stellar mass, and is heavily enriched in dust, with a dust-to-gas ratio close to that of the Milky Way. Dusty, evolved galaxies are thus present among the fainter star-forming population at $z > 7$, in spite of the very short time since they first appeared.
AB - Candidates for the modest galaxies that formed most of the stars in the early universe, at redshifts $z > 7$, have been found in large numbers with extremely deep restframe-UV imaging. But it has proved difficult for existing spectrographs to characterise them in the UV. The detailed properties of these galaxies could be measured from dust and cool gas emission at far-infrared wavelengths if the galaxies have become sufficiently enriched in dust and metals. So far, however, the most distant UV-selected galaxy detected in dust emission is only at $z = 3.25$, and recent results have cast doubt on whether dust and molecules can be found in typical galaxies at this early epoch. Here we report thermal dust emission from an archetypal early universe star-forming galaxy, A1689-zD1. We detect its stellar continuum in spectroscopy and determine its redshift to be $z = 7.5\pm0.2$ from a spectroscopic detection of the Ly{\alpha} break. A1689-zD1 is representative of the star-forming population during reionisation, with a total star-formation rate of about 12M$_\odot$ yr$^{-1}$. The galaxy is highly evolved: it has a large stellar mass, and is heavily enriched in dust, with a dust-to-gas ratio close to that of the Milky Way. Dusty, evolved galaxies are thus present among the fainter star-forming population at $z > 7$, in spite of the very short time since they first appeared.
KW - astro-ph.GA
U2 - 10.1038/nature14164
DO - 10.1038/nature14164
M3 - Journal article
C2 - 25731171
VL - 519
SP - 327
EP - 330
JO - Nature
JF - Nature
SN - 0028-0836
ER -
ID: 152270611