​Webb Telescope Captures Images of 19 Spiral Galaxies

Webb Telescope Captures Images of 19 Spiral Galaxies

韦伯望远镜捕捉到19个螺旋星系的图像

--------------------------------------------------------------------------------

　　By Dan Novak

　　03 February 2024

　　Newly released images captured by the James Webb Space Telescope show 19 spiral galaxies relatively close to our Milky Way. The images offer new information on star formation, galaxy structure and evolution.

　　The images were made public on Monday by a team of scientists involved in a project called Physics at High Angular resolution in Nearby GalaxieS (PHANGS). The project operates across several major astronomical observatories.

　　The closest of the 19 galaxies is called NGC5068. It is about 15 million light years from Earth. The most distant is NGC1365, about 60 million light years from Earth. A light year is the distance light travels in a year, which is equal to about 9.5 trillion kilometers.

　　The James Webb Space Telescope (JWST) was launched in 2021 and began collecting data in 2022. It has shaped understanding of the early universe while taking pictures of space.

　　The orbiting telescope looks at the universe mainly in the infrared. The Hubble Space Telescope, which was launched in 1990 and is still in use, has examined the universe mostly at optical and ultraviolet wavelengths.

　　Spiral galaxies are a common galaxy type. Our Milky Way is one.

　　The new observations came from Webb's Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI). They show about 100,000 star clusters and millions, or even billions, of individual stars.

　　"These data are important as they give us a new view on the earliest phase of star formation," said University of Oxford astronomer Thomas Williams. He led the team's data processing on the images.

　　Williams added, "Stars are born deep within dusty clouds that completely block out the light at visible wavelengths - what the Hubble Space Telescope is sensitive to - but these clouds light up at the JWST wavelengths. We don't know a lot about this phase."

　　About half of spiral galaxies have a straight structure, called a bar, coming out from the center. The spiral arms attach to this structure.

　　Williams said the commonly held thought is that galaxies form from the inside out. That way, they "get bigger and bigger over their lifetimes."

　　The images let scientists for the first time determine the structure of the clouds of dust and gas from which stars and planets form at a high level of detail.

　　The images are in galaxies beyond the Large Magellanic Cloud and Small Magellanic Cloud. Those two galaxies are near the Milky Way.

　　Webb's observations build on Hubble's.

　　Erik Rosolowsky is an astronomer at Canada's University of Alberta. He said, "Using Hubble, we would see the starlight from galaxies, but some of the light was blocked by the dust of galaxies."

　　Rosolowsky added, "This limitation made it hard to understand parts of how a galaxy operates as a system. With Webb's view in the infrared, we can see through this dust to see stars behind and within the enshrouding dust."

　　I'm Dan Novak.

　　Dan Novak adapted this story for VOA Learning English based on reporting by Reuters.

--------------------------------------------------------------------------------

　　由Dan Novak撰写

　　2024年2月3日

　　詹姆斯·韦伯太空望远镜新近发布的图像显示了19个相对接近我们的银河系的螺旋星系。这些图像提供了关于星体形成、星系结构和演化的新信息。

　　这些图像是由一个名为PHANGS（近邻星系高角分辨率物理学）项目的科学家团队在周一公开的。该项目在几个主要的天文观测站进行。

　　这19个星系中最近的被称为NGC5068，距离地球大约1500万光年。最远的是NGC1365，距离地球大约6000万光年。光年是光在一年中行走的距离，相当于大约9.5万亿公里。

　　詹姆斯·韦伯太空望远镜（JWST）于2021年发射，并于2022年开始收集数据。它在拍摄太空照片的同时，塑造了我们对早期宇宙的理解。

　　这个在轨望远镜主要以红外线观察宇宙。而1990年发射并仍在使用的哈勃太空望远镜，主要在光学和紫外线波长上检查宇宙。

　　螺旋星系是一种常见的星系类型。我们的银河系就是其中之一。

　　新的观察结果来自韦伯的近红外相机（NIRCam）和中红外仪器（MIRI）。它们显示了大约100,000个星团和数百万，甚至数十亿的单个星星。

　　"这些数据很重要，因为它们给了我们一个新的视角来看待星体形成的最早阶段，"牛津大学的天文学家托马斯·威廉姆斯说。他领导了团队对这些图像的数据处理。

　　威廉姆斯补充说："星星是在尘云深处诞生的，这些尘云完全阻挡了可见波长的光 - 哈勃太空望远镜对此敏感 - 但是这些云在JWST波长下发光。我们对这个阶段的了解并不多。"

　　大约一半的螺旋星系有一个从中心伸出的直线结构，被称为酒吧。螺旋臂连接到这个结构。

　　威廉姆斯说，普遍认为的观点是星系是从内部向外形成的。这样，它们在其生命周期中"变得越来越大"。

　　这些图像让科学家首次能够确定星星和行星形成的尘埃和气体云的结构，具有高度的细节。

　　这些图像是在大麦哲伦云和小麦哲伦云之外的星系中。这两个星系靠近银河系。

　　韦伯的观察结果是基于哈勃的。

　　埃里克·罗索洛夫斯基是加拿大阿尔伯塔大学的一位天文学家。他说："使用哈勃，我们可以看到来自星系的星光，但是一些光被星系的尘埃阻挡了。"

　　罗索洛夫斯基补充说："这个限制使我们很难理解星系作为一个系统是如何运作的。有了韦伯在红外线下的视野，我们可以看穿这个尘埃，看到尘埃后面和尘埃内部的星星。"

　　我是丹·诺瓦克。

　　丹·诺瓦克根据路透社的报道为VOA学习英语改编了这个故事。

--------------------------------------------------------------------------------

　　这个故事中的词汇

　　spiral — n. 一条围绕中心点的曲线，它在靠近或远离中心点的同时旋转

　　infrared — n. 产生或使用看不见的光线，这些光线比产生红光的光线长

　　cluster — n.一群靠在一起的事物或人

　　phase — n. 过程中的一部分或步骤

　　determine — v. 因为证据或事实而正式决定

　　dust — n. 在没有最近清洁的表面上积累的细小干燥粉末

　　enshroud — v. 以一种使看或理解变得困难的方式覆盖