This NASA/ESA Hubble Space Telescope image features a peculiar spiral galaxy called Arp 184 or NGC 1961.
ESA/Hubble & NASA, J. Dalcanton, R. J. Foley (UC Santa Cruz), C. Kilpatrick
A beautiful but skewed spiral galaxy dazzles in this NASA/ESA Hubble Space Telescope image. The galaxy, called Arp 184 or NGC 1961, sits about 190 million light-years away from Earth in the constellation Camelopardalis (The Giraffe).
The name Arp 184 comes from the Atlas of Peculiar Galaxies compiled by astronomer Halton Arp in 1966. It holds 338 galaxies that are oddly shaped and tend to be neither entirely elliptical nor entirely spiral-shaped. Many of the galaxies are in the process of interacting with other galaxies, while others are dwarf galaxies without well-defined structures. Arp 184 earned its spot in the catalog thanks to its single broad, star-speckled spiral arm that appears to stretch toward us. The galaxy’s far side sports a few wisps of gas and stars, but it lacks a similarly impressive spiral arm.
This Hubble image combines data from three Snapshot observing programs, which are short observations that slotted into time gaps between other proposals. One of the three programs targeted Arp 184 for its peculiar appearance. This program surveyed galaxies listed in the Atlas of Peculiar Galaxies as well as A Catalogue of Southern Peculiar Galaxies and Associations, a similar catalog compiled by Halton Arp and Barry Madore.
The remaining two Snapshot programs looked at the aftermath of fleeting astronomical events like supernovae and tidal disruption events — like when a supermassive black hole rips a star apart after it wanders too closely. Since Arp 184 hosted four known supernovae in the past three decades, it is a rich target for a supernova hunt.
Image credit: ESA/Hubble & NASA, J. Dalcanton, R. J. Foley (UC Santa Cruz), C. Kilpatrick
这张由NASA/ESA哈勃太空望远镜拍摄的图像展示了一座美丽而不对称的螺旋星系，名为Arp 184或NGC 1961。
图像来源: ESA/Hubble & NASA, J. Dalcanton, R. J. Foley (UC Santa Cruz), C. Kilpatrick
Arp 184坐落在鹿豹座（Camelopardalis）内，距离地球约1.9亿光年。尽管它是一座螺旋星系，却展现出偏离常规的形态，其结构令人惊艳。
Arp 184这一名称来源于天文学家哈顿·阿普（Halton Arp）于1966年编纂的《特殊星系图集》。该图集中收录了338个形状奇特的星系，它们往往既不完全是椭圆形，也不完全是螺旋形。许多星系正处于与其他星系的相互作用过程中，也有一些是结构不清晰的矮星系。Arp 184因其独特的外形被收录在该图集中：它拥有一条宽大、布满恒星的螺旋臂，看似正朝我们延伸。而星系远侧则仅有几缕气体和恒星，缺乏对称的螺旋结构。
这张图像融合了三个快照观测计划（Snapshot programs）中的数据。这些观测利用了哈勃望远镜在其他提案之间的时间空档，进行简短但高效的观测。其中一个计划专门针对形态特殊的星系，如Arp 184，观测目标包括《特殊星系图集》及其扩展版本《南部特殊星系与星系团图集》中列出的天体，这一扩展图集由哈顿·阿普与巴里·马多尔（Barry Madore）共同编撰。
其余两个观测计划则关注短暂天文事件的后续现象，例如超新星爆发和潮汐破坏事件（如超大质量黑洞因恒星靠得太近而将其撕裂）。过去三十年里，Arp 184已发生过四次已知超新星爆发，因此成为超新星搜寻研究的极佳目标。
图像来源: ESA/Hubble & NASA, J. Dalcanton, R. J. Foley (UC Santa Cruz), C. Kilpatrick
