A dusty, normal galaxy in the epoch of reionization

被引:290
作者
Watson, Darach [1 ]
Christensen, Lise [1 ]
Knudsen, Kirsten Kraiberg [2 ]
Richard, Johan [3 ]
Gallazzi, Anna [1 ,4 ]
Michalowski, Michal Jerzy [5 ]
机构
[1] Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, DK-2100 Copenhagen O, Denmark
[2] Chalmers Univ Technol, Onsala Space Observ, Dept Earth & Space Sci, SE-43992 Onsala, Sweden
[3] Univ Lyon 1, Ctr Rech Astrophys Lyon, F-69561 St Genis Laval, France
[4] Osserv Astrofis Arcetri, Ist Nazl Astrofis, I-50125 Florence, Italy
[5] Univ Edinburgh, Royal Observ, Inst Astron, Scottish Univ Phys Alliance, Edinburgh EH9 3HJ, Midlothian, Scotland
基金
英国科学技术设施理事会; 瑞典研究理事会; 欧洲研究理事会; 新加坡国家研究基金会;
关键词
STAR-FORMING GALAXIES; SIMILAR-TO; 7; LYMAN BREAK GALAXIES; SUBMILLIMETER GALAXIES; PHYSICAL-PROPERTIES; STARBURST GALAXY; MOLECULAR GAS; SIMPLE-MODEL; REDSHIFT; ULTRAVIOLET;
D O I
10.1038/nature14164
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
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-ultraviolet imagingl. But it has proved difficult for existing spectrographs to characterize them using their ultraviolet light(2-4). 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 galaxy discovered via its ultraviolet emission and subsequently detected in dust emission is only at z = 3.2 (ref. 5), and recent results have cast doubt on whether dust and molecules can be found in typical galaxies at z >= 7(6-8). Here we report thermal dust emission from an archetypal early Universe star-forming galaxy, A1689-zDI. We detect its stellar continuum in spectroscopy and determine its redshift to be z = 7.5 +/- 0.2 from a spectroscopic detection of the Lyman-a break. A1689-zD1 is representative of the star-forming population during the epoch of reionization(9), with a total star-formation rate of about 12 solar masses per year. 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.
引用
收藏
页码:327 / +
页数:13
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