An international team of astronomers today announced the discovery using NASA’s James Webb Space Telescope (JWST) of the two earliest and most distant galaxies yet confirmed, dating back to only 300 million years after the Big Bang. These galaxies mark a major milestone in the study of the early universe and were discovered by the JWST Advanced Deep Extragalactic Survey (JADES) team, co-led by UC Santa Cruz astronomer Brant Robertson.
一个国际天文学家小组今天宣布，他们使用美国宇航局的詹姆斯·韦伯太空望远镜(JWST)发现了迄今为止确认的两个最早、最遥远的星系，它们可以追溯到大爆炸后仅3亿年。这些星系标志着早期宇宙研究的一个重要里程碑，是由加州大学圣克鲁斯分校天文学家布兰特·罗伯逊共同领导的JWST高级深河外巡天(JADES)小组发现的。
“This discovery is completely unanticipated and is likely to be seen as the most significant extragalactic discovery with JWST to date,” said Robertson, an astronomy and astrophysics professor who sits on the JADES steering committee. He is the lead author on the first of three papers reporting various aspects of the discovery.
“这一发现完全出乎意料，很可能被视为迄今为止JWST最重要的星系外发现，”天文学和天体物理学教授、JADES指导委员会成员罗伯逊说。他是报告该发现各个方面的三篇论文中的第一篇的主要作者。
In one paper, the authors conclude: “This demonstrates the immediate impact new JWST observations can have on our knowledge of the distant universe. With high-redshift galaxy populations now established fewer than 300 million years after the Big Bang, we have extended our reach into the cosmic past by 40% during the first eighteen months of JWST operations.”
在一篇论文中，作者总结道:“这证明了新的JWST观测结果可以对我们对遥远宇宙的认识产生直接影响。在宇宙大爆炸后不到3亿年的时间里，高红移星系群已经建立起来，在JWST运作的前18个月里，我们已经将我们对宇宙过去的研究范围扩大了40%。”
“Redshift” refers to an effect caused by the expansion of the universe, where the wavelength of light from distant galaxies stretches as it travels. In these newly discovered galaxies, the effect is extreme — stretching by a factor of 15, and moving even the ultraviolet light of the galaxies to infrared wavelengths where only JWST has the capability to see it.
“红移”指的是由宇宙膨胀引起的一种效应，即来自遥远星系的光在传播过程中波长会拉长。在这些新发现的星系中，这种效应是极端的——被拉伸了15倍，甚至星系的紫外线也被移动到只有JWST才能看到的红外波长。
Chasing early galaxies
追逐早期星系
Modern theory holds that galaxies develop in special regions where gravity has concentrated cosmic gas and dark matter into dense lumps known as “halos.” These halos evolve quickly in the early universe, merging into more and more massive collections of matter. This rapid development is why astronomers are so eager to find yet earlier galaxies: Each small increment moves our eyes to a less developed period, where brighter galaxies are even more distinctive and unusual.
现代理论认为，星系是在特殊区域形成的，在那里，引力将宇宙气体和暗物质聚集成密集的团块，称为“光晕”。这些光晕在早期宇宙中迅速演化，融合成越来越大的物质集合。这种快速的发展就是为什么天文学家如此渴望发现更早的星系:每一个小的增长都将我们的目光转移到一个不太发达的时期，在这个时期，更明亮的星系更加独特和不寻常。
Found in a region near the Hubble Ultra Deep Field, the two newly discovered galaxies have been confirmed spectroscopically. In keeping with the collaboration’s standard naming practice, the galaxies are now known as JADES-GS-z14-0 and JADES-GS-z14-1, the former being the more distant of the two.
这两个新发现的星系位于哈勃超深场附近的一个区域，已经在光谱上得到了证实。为了与合作的标准命名惯例保持一致，这两个星系现在被称为JADES-GS-z14-0和JADES-GS-z14-1，前者是两个星系中距离较远的。
In addition to being the new distance record holder, JADES-GS-z14-0 is remarkable for how big and bright it is. JWST measures the galaxy at over 1,600 light-years in diameter. Many of the most luminous galaxies produce the bulk of their light via gas falling into a supermassive black hole, producing a quasar. But the team says the large size of JADES-GS-z14-0 means that the light must be produced by young stars.
除了成为新的距离记录保持者外，jade - gs -z14-0还因其巨大和明亮而引人注目。JWST测量的星系直径超过1600光年。许多最明亮的星系的大部分光都是通过气体落入超大质量黑洞产生的，从而产生类星体。但研究小组表示，JADES-GS-z14-0的大尺寸意味着这些光一定是由年轻的恒星产生的。
Deeply hidden gems
深藏不露的宝石
And yet, the massive galaxy was a puzzle for the JADES team when they first spotted it over a year ago, as it appears close enough on the sky to a foreground galaxy that they couldn’t be sure that the two weren’t neighbors. But in October 2023, the JADES team conducted even deeper imaging—five full days with the JWST Near-Infrared Camera on just one field—to form the “JADES Origins Field.” With the use of filters designed to better isolate early galaxies, confidence grew that JADES-GS-z14-0 was indeed very distant.
除了成为新的距离记录保持者外，jade - gs -z14-0还因其巨大和明亮而引人注目。JWST测量的星系直径超过1600光年。许多最明亮的星系的大部分光都是通过气体落入超大质量黑洞产生的，从而产生类星体。但研究小组表示，JADES-GS-z14-0的大尺寸意味着这些光一定是由年轻的恒星产生的。
In addition, the galaxy happened to fall in a region where the team had conducted ultra-deep imaging with the JWST Mid-InfraRed Instrument. These combined imaging results convinced the team to include the galaxy in what was planned to be the capstone observation of JADES, a 75-hour campaign to conduct spectroscopy on faint early galaxies. The spectroscopy confirmed their hopes that JADES-GS-z14-0 was indeed a record-breaking galaxy — and that the fainter candidate, JADES-GS-z14-1, was nearly as far away.
此外，该星系恰好落在该团队用JWST中红外仪器进行超深成像的区域。这些综合成像结果说服了研究小组将这个星系包括在JADES的顶点观测中，JADES是一个75小时的活动，对微弱的早期星系进行光谱分析。光谱学证实了他们的希望，JADES-GS-z14-0确实是一个破纪录的星系，而更微弱的候选星系JADES-GS-z14-1也几乎同样遥远。
The combination of the high luminosity and the stellar origin makes JADES-GS-z14-0 the most distinctive evidence yet for the rapid formation of large, massive galaxies in the early universe. “We could have detected this galaxy even if it were 10 times fainter, which means that we could see other examples yet earlier in the universe—probably into the first 200 million years,” Robertson said. “This galaxy is truly a gem, and it points at more hidden treasures in the early universe.”
高亮度和恒星起源的结合使JADES-GS-z14-0成为早期宇宙中快速形成大型大质量星系的最独特证据。罗伯逊说:“我们可以探测到这个星系，即使它比现在暗淡10倍，这意味着我们可以看到宇宙中更早的其他例子——可能是在最初的2亿年。”“这个星系确实是一块宝石，它指向了早期宇宙中更多隐藏的宝藏。”
Robertson’s paper, “Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic Star-Formation Rate Density 300 Myr after the Big Bang,” is accepted for publication in the Astrophysical Journal.
罗伯逊的论文《JADES起源领域最早的星系:大爆炸后亮度函数和宇宙恒星形成速率密度300 Myr》被《天体物理学杂志》接受发表。
The James Webb Space Telescope is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency). For more information, see NASA’s announcement.
詹姆斯·韦伯太空望远镜是由美国国家航空航天局及其合作伙伴欧洲航天局和加拿大航天局领导的一个国际项目。欲了解更多信息，请参阅NASA的公告。
