这张复合图片展示了来自一个星系中心黑洞产生的发射物撞击另一个星系边缘景象，在第1次观测中这个相互作用就已经被发现。在这帐图中，来自多波段的数据被整合到了一起。X射线是来自钱德拉（以紫色标记），可见光和紫外线来自哈勃（红色和橙色），射电信号来自VLA和MERLIN（蓝色），这些图片展现了左下方的主星系和右上方的同伴星系碰撞后是怎样产生发射物的。发射物撞击同伴星系边缘后便断裂，同时也转向了，这和来自皮管的水流在遇到墙角时会被削弱是一个道理。
撞击星系发射物的插图在每一个波段都展示了名叫3c321系统的不同面貌。钱德拉所拍摄的图提供了每个星系中心都包含了一个超大质量的快速成长黑洞的证据。哈勃的可加光图片（橙色）展示了每个星系里恒星的发光。VLA和MERLIN图片中明亮的亮点表明了发射物与星系一侧的撞击位点。—大约距离主星系20000光年处—耗费了其一些能量一个巨大的射电“热源”被VLA探测到并展示出发射物轨迹终止于距离星系非常遥远的地方，大约850000光年。哈勃紫外图片表明星系附近拥有巨大数量的热气体，这指明在存在于两个星系中超大质量的黑洞有着疯狂的过去。钱德拉、哈勃和斯必泽所拍摄到的不明显的发射，没在这张图片中，但这表明星系以顺时针方向运动，同时也暗示其同伴星系以发射物的路进转动。活泼的3c321
来自钱德拉的数据显示粒子加速仍然在热源中发生，说明在近期发射物必定已经撞击了同伴星系，不到100万年前。这个相对来说比较短的宇宙时间范围内发生了罕见的现象。
这个“死亡的恒星星系”将制造出大量的高能射线，而这些射线能导致对任何位于同伴星系内并处于发射物路径中的行星大气层的严重破坏。地球处于来自超大质量黑洞产生发射物的“枪口”方向，但是这些被叫做耀变体的天体处于一个对于我们来说非常安全的距离位置上，成万上亿光年。
This composite image shows the jet from a black hole at the center of a galaxy striking the edge of another galaxy, the first time such an interaction has been found. In the image, data from several wavelengths have been combined. X-rays from Chandra (colored purple), optical and ultraviolet (UV) data from Hubble (red and orange), and radio emission from the Very Large Array (VLA) and MERLIN (blue) show how the jet from the main galaxy on the lower left is striking its companion galaxy to the upper right. The jet impacts the companion galaxy at its edge and is then disrupted and deflected, much like how a stream of water from a hose will splay out after hitting a wall at an angle.
Illustration of Jet Striking Galaxy (unlabeled) Each wavelength shows a different aspect of this system, known as 3C321. The Chandra X-ray image provides evidence that each galaxy contains a rapidly growing supermassive black hole at its center. Hubble's optical light images (orange) show the glow from the stars in each galaxy. A bright spot in the VLA and MERLIN radio image shows where the jet has struck the side of the galaxy - about 20,000 light years from the main galaxy - dissipating some of its energy. An even larger "hotspot" of radio emission detected by VLA (seen in an image with a much larger field-of-view) reveals that the jet terminates much farther away from the galaxy, at a distance of about 850,000 light years away. The Hubble UV image shows large quantities of warm and hot gas in the vicinity of the galaxies, indicating the supermassive black holes in both galaxies have had a violent past. Faint emission from Chandra, Hubble and Spitzer, not shown in this image, indicate that the galaxies are orbiting in a clockwise direction, implying that the companion galaxy is swinging into the path of the jet. Animation of 3C321
Since the Chandra data shows that particle acceleration is still occurring in this hotspot, the jet must have struck the companion galaxy relatively recently, less than about a million years ago (i.e. less than the light travel time to the hotspot). This relatively short cosmic time frame makes this event a very rare phenomenon.
This "death star galaxy" will produce large amounts of high-energy radiation, which may cause severe damage to the atmospheres of any planets in the companion galaxy that lie in the path of the jet. From the Earth we look down the barrel of jets from supermassive black holes, however these so-called "blazars" are at much safer distances of millions or billions of light years.
自翻
URL：http://chandra.harvard.edu/photo/2007/3c321/
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[ 本帖最后由 江涛 于 2008-3-18 17:07 编辑 ] |
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