ABOUT THIS IMAGE:On July 4, fireworks blaze over the skies of American cities in the annual Independence Day celebrations.
But nearly 12.5 million light-years away in the dwarf galaxy NGC 4449 stellar "fireworks" are going off all the time.
Hundreds of thousands of vibrant blue and red stars blaze in this image taken by NASA's Hubble Space Telescope. Hot bluish-white clusters of massive stars are scattered throughout the galaxy, interspersed with numerous dustier, reddish regions of current star formation. Massive dark clouds of gas and dust are silhouetted against the starlight.
NGC 4449 has been forming stars for several billion years, but currently it is experiencing a star formation event at a much higher rate than in the past. This unusually explosive and intense star formation activity qualifies as a starburst. At the current rate, the gas supply that feeds the stellar production would only last for another billion years or so.
Starbursts usually occur in the central regions of galaxies, but NGC 4449 has more widespread star formation activity, since the very youngest stars are observed both in the nucleus and in streams surrounding the galaxy.
A "global" starburst like NGC 4449 resembles primordial star forming galaxies, which grew by merging with and accreting smaller stellar systems. Since NGC 4449 is close enough to be observed in great detail, it is the ideal laboratory for the investigation of what may have occurred during galactic formation and evolution in the early universe.
It's likely that the current widespread starburst was triggered by interaction or merging with a smaller companion. NGC 4449 belongs to a group of galaxies in the constellation Canes Venatici. Astronomers think that NGC 4449's star formation has been influenced by interactions with several of its neighbors.
This image was taken in November 2005 by an international science team led by Alessandra Aloisi of the Space Telescope Science Institute (STScI) in Baltimore and the European Space Agency (ESA). Other team members include Francesca Annibali (STScI), Claus Leitherer (STScI), Jennifer Mack (STScI), Marco Sirianni (STScI/ESA), Monica Tosi (INAF-OAB), and Roeland van der Marel (STScI).
Hubble's Advanced Camera for Surveys observed the NGC 4449 in blue, visible, infrared, and H-alpha light.
For additional information, contact:
Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone: 410-338-4514; E-mail: villard@stsci.edu)
Lars Lindberg Christensen
ESA/Hubble/ST-ECF, Garching, Germany
(Phone: 49-89-320-06-306; E-mail: lars@eso.org)
Alessandra Aloisi
Space Telescope Science Institute/European Space Agency, Baltimore, Md.
(Phone: 410-338-4519; E-mail: aloisi@stsci.edu)
Object Name: NGC 4449
Image Type: Astronomical
Credit: NASA, ESA, A. Aloisi (STScI/ESA), and The Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration
图片说明:哈勃太空望远镜观察到了1250万光年外的一场绚丽“宇宙烟花”。与地球上转瞬即逝的烟花不同，这场“宇宙烟花”可能要持续10亿年。
美国宇航局和欧洲航天局7月3日发布了哈勃太空望远镜对矮星系NGC4449拍摄的一张照片，它展现了这个星系中恒星诞生的情景。在照片上，数以百计的蓝色和红色恒星闪闪发光，由大恒星组成的蓝白色星簇遍布各处，新的恒星正在弥漫的红色尘云中诞生。
NGC4449是猎犬座方向上一群星系中的一个，天文学家认为这个星系里的恒星诞生受到了一些邻近星系的影响。恒星在星系中诞生是很普通的事，但目前NGC4449里的恒星诞生活动格外剧烈，达到了“星暴”的程度，据分析这可能是该星系与另一个较小星系碰撞融合所致。天文学家说，以目前消耗速度计算，该星系里的气体尘云还能使这场“宇宙烟花”盛放10亿年。
“星暴”通常只在星系中央出现，但NGC4449里的“星暴”范围要广得多，在环绕星系的气流中也发生了，这意味着该星系与宇宙中孕育早期恒星的原初星系很相似。由于距离相对较近，利于观察，该星系将是一个检验早期宇宙中星系形成和演化理论的理想实验室。
来源:http://hubblesite.org/newscenter ... es/2007/26/image/a/以下这幅图片由哈勃空间望远镜拍摄。
以下内容由[Eldghost]添加，来源：Rojer 同好的原创翻译帖（内容重复帖，已锁），可以对比上文来看，
感谢Rojer的劳动成果！
http://www.astronomy.com.cn/bbs/viewthread.php?tid=71924&extra=page%3D9%26amp%3Bfilter%3D7948800%26amp%3Borderby%3Ddateline
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NGC4449
July 4, 2007
Nearly 12.5 million light-years away in the dwarf galaxy NGC 4449, a veritable stellar "fireworks" is on display. With the powerful "eyes" of the Hubble Space Telescope, we are able to see this distant show in exquisite detail.
在近1.25亿光年远的矮星系 NGC4449 中，正在展现一场真正的恒星“烟火”。借助强大的“哈勃”之眼我们得以看到这场遥远表演的精美细节。
Hundreds of thousands of vibrant blue and red stars are visible in this new image of galaxy NGC 4449 taken by the NASA/ESA Hubble Space Telescope. Hot bluish white clusters of massive stars are scattered throughout the galaxy, interspersed with numerous dustier reddish regions of current star formation. Massive dark clouds of gas and dust are silhouetted against the flaming starlight.
在这张由NASA/ESA的“哈勃”空间望远镜拍摄的图片中可以看到成百上千充满活力的蓝色和红色恒星。炽热的蓝白色大质量恒星群遍布整个星系，散布在众多充满尘埃略带红色的恒星诞生区中。大量气体和尘埃的暗云在炽热的星光下形成剪影。
NGC 4449 has been forming stars over several billion years, but currently it is experiencing a star formation event at a much higher rate than in the past. This unusual explosive and intense star formation activity qualifies as a starburst. At the current rate, the gas supply that feeds the stellar production would only last for another billion years or so.
NGC4449 中形成恒星已经有数亿年了，但是现在它正以比以往高得多的速率形成恒星。这种不寻常的爆发和剧烈的恒星形成活动有星暴的资格。以现在的速率，供给产生恒星的气体最多只能再维持1亿年左右。
Starbursts usually occur in the central regions of galaxies, but NGC 4449 has a more widespread star formation activity, since the very youngest stars are observed both in the nucleus and in streams surrounding the galaxy.
星暴通常出现在星系的中心区域，但是 NGC4449 有着更广泛的恒星形成活动，因为在核球和环绕星系的星流中都能观测到非常年轻的恒星。
A "global" starburst like NGC 4449 resembles primordial star forming galaxies which grew by merging with and accreting smaller stellar systems. Since NGC 4449 is close enough to be observed in great detail, it is the ideal laboratory for the investigation of what may have occurred during galactic formation and evolution in the early Universe.
像 NGC4449 这样的整体星暴类似于最原始的恒星形成星系，这些星系通过与较小恒星系统的合并和共生来成长起来。由于 NGC4449 离的比较近能观测到主要的细节，它成为调查在宇宙早期星系形成和演化中到底发生了什么的理想试验室。
It’s likely that the current widespread starburst was triggered by interaction or merging with a smaller companion. NGC 4449 belongs to a group of galaxies in the constellation Canes Venatici, the Hunting Dogs. Astronomers think that NGC 4449’s star formation has been influenced by interactions with several of its neighbors.
当前广泛分布的星暴似乎是被同一个小伙伴的相互作用或合并所触发。NGC4449 属于猎犬座中的一个星系群。天文学家认为 NGC4449 的恒星形成是受到其数个邻居性互作用的影响。
[ 本帖最后由 寻找拉玛 于 2007-12-16 15:55 编辑 ] |
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