哈勃的海豚星系影像

哈勃的海豚星系影像

ByNASA中文

2020 May 10 The Porpoise Galaxy from Hubble Image Credit: NASA, ESA, Hubble, HLA; Reprocessing & Copyright: Raul Villaverde Explanation: What’s happening to this spiral galaxy? Just a few hundred million years ago, NGC 2936, the upper of the two large galaxies shown, was likely a normal spiral galaxy — spinning, creating stars — and minding its own business. But then it got too close to the massive elliptical galaxy NGC 2937 below and took a dive. Dubbed the Porpoise Galaxy for its iconic shape, NGC 2936 is not only being deflected but also being distorted by the close gravitational interaction. A burst of young blue stars forms the nose of the porpoise toward the right of the upper galaxy, while the center of the…

M77：有活跃核心的螺旋星系

M77：有活跃核心的螺旋星系

ByNASA中文

2020 March 17 M77: Spiral Galaxy with an Active Center Image Credit: Hubble, NASA, ESA; Processing & License: Judy Schmidt Explanation: What’s happening in the center of nearby spiral galaxy M77? The face-on galaxy lies a mere 47 million light-years away toward the constellation of the Sea Monster (Cetus). At that estimated distance, this gorgeous island universe is about 100 thousand light-years across. Also known as NGC 1068, its compact and very bright core is well studied by astronomers exploring the mysteries of supermassive black holes in active Seyfert galaxies. M77 and its active core glows bright at x-ray, ultraviolet, visible, infrared, and radio wavelengths. The featured sharp image of M77 was taken by the Hubble Space Telescope and is dominated by the (visible) red…

星系NGC 7331的特写影像

星系NGC 7331的特写影像

ByNASA中文

2020 February 7 NGC 7331 Close Up Image Credit & License: ESA/Hubble & NASA/D. Milisavljevic (Purdue University) Explanation: Big, beautiful spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way. About 50 million light-years distant in the northern constellation Pegasus, NGC 7331 was recognized early on as a spiral nebula and is actually one of the brighter galaxies not included in Charles Messier’s famous 18th century catalog. Since the galaxy’s disk is inclined to our line-of-sight, long telescopic exposures often result in an image that evokes a strong sense of depth. In this Hubble Space Telescope close-up, the galaxy’s magnificent spiral arms feature dark obscuring dust lanes, bright bluish clusters of massive young stars, and the telltale reddish glow of…

鲁宾的星系

鲁宾的星系

ByNASA中文

2020 January 25 Rubin’s Galaxy Image Credit: NASA, ESA, B. Holwerda (University of Louisville) Explanation: In this Hubble Space Telescope image the bright, spiky stars lie in the foreground toward the heroic northern constellation Perseus and well within our own Milky Way galaxy. In sharp focus beyond is UGC 2885, a giant spiral galaxy about 232 million light-years distant. Some 800,000 light-years across compared to the Milky Way’s diameter of 100,000 light-years or so, it has around 1 trillion stars. That’s about 10 times as many stars as the Milky Way. Part of a current investigation to understand how galaxies can grow to such enormous sizes, UGC 2885 was also part of astronomer Vera Rubin’s pioneering study of the rotation of spiral galaxies. Her work…

NGC247和伙伴们

NGC247和伙伴们

ByNASA中文

2020 January 16 NGC 247 and Friends Image Credit & Copyright: Acquisition – Eric Benson, Processing – Dietmar Hager Explanation: About 70,000 light-years across, NGC 247 is a spiral galaxy smaller than our Milky Way. Measured to be only 11 million light-years distant it is nearby though. Tilted nearly edge-on as seen from our perspective, it dominates this telescopic field of view toward the southern constellation Cetus. The pronounced void on one side of the galaxy’s disk recalls for some its popular name, the Needle’s Eye galaxy. Many background galaxies are visible in this sharp galaxy portrait, including the remarkable string of four galaxies just below and left of NGC 247 known as Burbidge’s Chain. Burbidge’s Chain galaxies are about 300 million light-years distant. NGC…

NASA哈勃太空望远镜观测巨型星系

NASA哈勃太空望远镜观测巨型星系

ByNASA中文

这个巨型螺旋星系或许会被称为“哥斯拉星系”（Godzilla galaxy），因为该星系有可能是其所在宇宙中已知的最大星系。该星系名为UGC 2885，比银河系宽2.5倍，其恒星数量则是银河系的10倍。 不过研究人员表示，UGC 2885星系是一个“温和的巨人”，因为它看上去没有与其他大型星系碰撞而过着相对静态的生活。在过去数十亿年间，它逐渐从星系间的丝状结构中吸收积累了氢，以缓慢而稳定的速度制造新恒星，其恒星诞生速率约为银河系的一半。事实上，该星系的超大质量中心黑洞也是一个沉睡的巨人。因为该星系似乎并不吞噬比它小得多的卫星星系，从而缺乏流入的气体。 肯塔基州路易斯维尔大学的本尼•霍尔维达（Benne Holwerda）用美国国家航空航天局（NASA）的哈勃太空望远镜对UGC 2885星系进行了观测，并以天文学家维拉•鲁宾（Vera Rubin，1928 – 2016）的名字给该星系起了个绰号，叫做“鲁宾星系”（Rubin’s galaxy）。 这张由哈勃太空望远镜拍摄的照片展示了巨型螺旋状星系UGC 2885，它位于距离地球2.32亿光年远的英仙座北部。该星系比银河系宽2.5倍，其恒星数量是银河系的10倍。在这幅图像中，我们可以看到银河系中的许多前景恒星，这些恒星可以通过它们的衍射峰来被识别。最亮的恒星在银河系的圆盘“乱入镜头”（photobomb）。该星系的昵称叫做“鲁宾星系”，以天文学家维拉•鲁宾（Vera Rubin ，1928-2016）的名字命名。 版权：NASA、欧洲航天局（ESA）和B. Holwerda（路易斯维尔大学） 霍尔维达表示：“我的研究在很大程度上受到了维拉•鲁宾在1980年关于UGC 2885星系大小的研究的启发”。维拉•鲁宾测量了该星系的旋转，并且由此发现了暗物质存在的证据，暗物质占据了该星系的大部分质量。“我们认为这是一个具有纪念意义的事情。在我们的观测中引用鲁宾博士的研究，这是我们最初的哈勃计划中的重要组成部分。” 霍尔维达于2020年1月6日在美国夏威夷檀香山举行的第235届美国天文学会年会上展示了其研究成果，试图解释了究竟是什么原因导致了UGC 2885星系的巨大规模。他表示：“我们目前还不太清楚该星系是如何变得这么庞大的。它的大小足以使其形成一个圆盘星系，而又不会触及任何其他空间。” 我们所知的一条线索是，UGC 2885星系在空间上是非常孤立的，并且附近没有任何星系可以撞击并破坏其圆盘形状。 随着时间的推移，UGC 2885星系是否吞噬了更小的卫星星系？抑或只是缓慢地为新恒星积累了气体？霍尔维达表示：“该星系似乎一直在缓慢生长。”利用哈勃太空望远镜的超高分辨率，霍尔维达的团队正在计算银河系光晕中的球状星团数量。大量星系团将会提供证据，证明它们是在数十亿年时间从被吞噬的较小星系中被捕获的。 NASA即将发射的詹姆斯•韦伯太空望远镜（James Webb Space Telescope）可以用来探测该星系的中心以及球状星团的数量。NASA计划中的广域红外探测望远镜（Wide Field Infrared Survey Telescope，WFIRST）将对其星系群，尤其是整个光环群进行更全面的普查。霍尔维达表示：“这两架太空望远镜的红外线捕捉能力将使我们更清楚地看到底层的恒星群。”这对哈勃太空望远镜可见光捕捉能力进行了补充，以追踪整个星系中稀疏的恒星形成。 在这幅图像中，我们可以看到银河系中的许多前景恒星，这些恒星可以通过其衍射峰来被识别。尽管UGC 2885星系实际上位于我们2.32亿光年之外的英仙座北部，其最明亮的部分看上去似乎位于星系盘的顶部。 来源： https://www.nasa.gov/feature/goddard/2020/nasas-hubble-surveys-gigantic-galaxy

M31：仙女座星系

M31：仙女座星系

ByNASA中文

2019 September 9 M31: The Andromeda Galaxy Image Credit & Copyright: Amir H. Abolfath (TWAN) Explanation: How far can you see? The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy, over two million light-years away. Without a telescope, even this immense spiral galaxy appears as an unremarkable, faint, nebulous cloud in the constellation Andromeda. But a bright yellow nucleus, dark winding dust lanes, luminous blue spiral arms, and bright red emission nebulas are recorded in this stunning six-hour telescopic digital mosaic of our closest major galactic neighbor. While even casual skygazers are now inspired by the knowledge that there are many distant galaxies like M31, astronomers seriously debated this fundamental concept only 100 years ago. Were these “spiral…

NGC 1499：加州星云

NGC 1499：加州星云

ByNASA中文

2019 August 23 NGC 1499: The California Nebula Image Credit & Copyright: Sara Wager Explanation: Drifting through the Orion Arm of the spiral Milky Way Galaxy, this cosmic cloud by chance echoes the outline of California on the west coast of the United States. Our own Sun also lies within the Milky Way’s Orion Arm, only about 1,500 light-years from the California Nebula. Also known as NGC 1499, the classic emission nebula is around 100 light-years long. The California Nebula shines with the telltale reddish glow characteristic of hydrogen atoms recombining with long lost electrons. The electrons have been stripped away, ionized by energetic starlight. Most likely providing the energetic starlight that ionizes much of the nebular gas is the bright, hot, bluish star Xi…

NGC 1566：西班牙舞者螺旋星系

NGC 1566：西班牙舞者螺旋星系

ByNASA中文

2019 July 2 NGC 1566：西班牙舞者螺旋星系 影像提供: NASA, ESA, Hubble; 图像处理与版权: Leo Shatz 说明: 如果长成这个模样还不够完美的话，那么至少这个螺旋星系是最上相者之一。拥有数十亿颗成员星，位在剑鱼座方向约4千万光年远处的宇宙岛 NGC 1566，以壮丽的正面对着我们。分类为宏伟螺旋星系的NGC 1566，拥有二道鲜明且优雅的螺旋臂，上头镶着明亮的泛蓝星团和黝黑的尘埃带。 哈伯太空望远镜过去曾为NGC 1566拍下大量的影像，以研究这个星系的恒星诞生、超新星和异常活跃的星系核。其中部分的影像存放在在线的哈伯遗珍数据库里，后来为由一位勤勉的业余工作者，免费下载、组合和数字处理成这幅主题影像。NGC 1566闪耀的星系核，让它成为离我们最近也最亮的西佛型螺旋星系，其核心可能藏着一颗超大质量的黑洞，不停肆虐周遭的恒星和气体。 NGC 1566: The Spanish Dancer Spiral Galaxy Image Credit: NASA, ESA, Hubble; Processing & Copyright: Leo Shatz Explanation: If not perfect, then this spiral galaxy is at least one of the most photogenic. An island universe containing billions of stars and situated about 40 million light-years away toward the constellation of the Dolphinfish (Dorado), NGC 1566 presents a gorgeous face-on view. Classified as a grand design spiral, NGC 1566’s shows two prominent and graceful spiral arms that are traced by bright blue star clusters and dark cosmic dust lanes. Numerous Hubble Space Telescope images of NGC 1566 have been taken to study star formation, supernovas,…