偶遇的星系冲撞英文原文
译:Jack

   
  在两个星系中,编号为 NGC 2207 (在图片左边那个)的,相对来说较大一点,而另外一个编号为IC 2163的,就要小一些了。从NGC 2207发出的强大的潮汐似的引力使得IC 2163的形状发生了扭曲,同时,也将其中的恒星和气体拋射到了离图片右沿大约一千光年的地方。

  Bruce 和Debra Elmegreen领导的小组,通过计算机的模拟,证明了两个星系冲撞的过程。 除了利用哈勃拍摄的照片,美国也用在新墨西哥的射电望远镜阵对正在冲撞的两个星系作了测量,当然,这些工作对重现星系冲撞的过程有着极大的作用。

  计算表明:IC 2163在逆时针方向穿过NGC 2207时,显得十分活跃,但是,IC 2163却没有足够的能量逃离它和NGC 2207之间的万有引力, IC 2163将会被NGC 2207的强大的引力拉回来,而且,还会再次经过NGC 2207。

  哈勃的高清晰度的照片展示了NGC 2207旋臂中的灰尘壮的路径,也显现出了在背景之中的NGC 2207的“倒影”倚着IC 2136。(见下图,点击放大)

                               更大的照片


  哈勃也显现了一系列相平行灰尘状延伸的行径,就像一个细小的刷子刷过右侧湿的富有弹性的材料一样。在不久的将来,这些大量集中的气体和灰尘可能向某些能够形成恒星的区域发生巨大的爆发。

  由于它们陷入了它们共同的“势力范围”内,这两个星系还会继续扭曲,甚至分裂对方。最后,在未来的几十亿年内,它们回渐渐的融合,从而形成一个共同体——一个新的、更大的星系。我们相信,我们现今所看到的星系,包括银河系,都是由一些小的星系在几十亿年前发生同样的融合而产生的。

   译自 摘自哈勃网站(http://oposite.stsci.edu

A Grazing Encounter Between Two Spiral Galaxies
Chinese Version


    The larger and more massive galaxy is cataloged as NGC 2207 (on the left in the Hubble Heritage image), and the smaller one on the right is IC 2163. Strong tidal forces from NGC 2207 have distorted the shape of IC 2163, flinging out stars and gas into long streamers stretching out a hundred thousand light-years toward the right-hand edge of the image.

    Computer simulations, carried out by a team led by Bruce and Debra Elmegreen, demonstrate the leisurely timescale over which galactic collisions occur. In addition to the Hubble images, measurements made with the National Science Foundation's Very Large Array Radio Telescope in New Mexico reveal the motions of the galaxies and aid the reconstruction of the collision.

 The calculations indicate that IC 2163 is swinging past NGC 2207 in a counterclockwise direction, having made its closest approach 40 million years ago. However, IC 2163 does not have sufficient energy to escape from the gravitational pull of NGC 2207, and is destined to be pulled back and swing past the larger galaxy again in the future.

 The high resolution of the Hubble telescope image reveals dust lanes in the spiral arms of NGC 2207, clearly silhouetted against IC 2163, which is in the background. Hubble also reveals a series of parallel dust filaments extending like fine brush strokes along the tidally stretched material on the right-hand side. The large concentrations of gas and dust in both galaxies may well erupt into regions of active star formation in the near future.

 Trapped in their mutual orbit around each other, these two galaxies will continue to distort and disrupt each other. Eventually, billions of years from now, they will merge into a single, more massive galaxy. It is believed that many present-day galaxies, including the Milky Way, were assembled from a similar process of coalescence of smaller galaxies occurring over billions of years.

   Copied From Hubble Web(http://oposite.stsci.edu

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