2019 October 3
The Hydrogen Clouds of M33
Image Data: Subaru Telescope (NAOJ), Hubble Space Telescope – Image Processing: Robert Gendler
Additional Data: BYU, Robert Gendler, Johannes Schedler, Adam Block – Copyright: Robert Gendler, Subaru Telescope, NAOJ
Explanation: Gorgeous spiral galaxy M33 seems to have more than its fair share of glowing hydrogen gas. A prominent member of the local group of galaxies, M33 is also known as the Triangulum Galaxy and lies a mere 3 million light-years away. The galaxy’s inner 30,000 light-years or so are shown in this magnificent 25 panel telescopic mosaic. Based on image data from space and ground-based telescopes, the portrait of M33 shows off the galaxy’s reddish ionized hydrogen clouds or HII regions. Sprawling along loose spiral arms that wind toward the core, M33’s giant HII regions are some of the largest known stellar nurseries, sites of the formation of short-lived but very massive stars. Intense ultraviolet radiation from the luminous, massive stars ionizes the surrounding hydrogen gas and ultimately produces the characteristic red glow. To enhance this image, broadband data was used to produce a color view of the galaxy and combined with narrowband data recorded through a hydrogen-alpha filter. That filter transmits the light of the strongest visible hydrogen emission line.
说明: 壮丽的螺旋星系M33看似拥有特别多的辉光氢气。距离约3百万光年远的M33，又名为三角座星系，是本星系群的一个大型成员。这幅由 25张望远镜照片拼接而成的影像，呈现其内围大约3万光年的区域。这些由太空及地面望远镜拍摄的影像数据，目的是要突显泛红名为HII区的电离氢气云。散布在M33星系核周围蜿蜒松散螺旋臂上的庞大HII区，是现知最大的一批恒星形成区，而它们也是生命短暂、极大质量恒星的家园。来自这些明亮大质量恒星的强烈紫外辐射，电离了周遭的氢气，让它们发出特征性的泛红辉光。为增加影像的对比，上图结合了宽波段的彩色星系影像与及透过氢-α滤镜拍摄，只透过最明亮的氢发射线（红光）之窄波段影像数据。