That is the supernova’s host galaxy.

那就是这颗超新星所在的星系。

So it's like a subhalo orbiting its host galaxy.

所以它就像一个围绕其宿主星系运行的子晕。

13. quasars are now thought to be black holes devouring material in the crowded centers of their host galaxies.

类星体现在被认为是吞噬宿主星系拥挤中心的物质的黑洞。

As the material coalesces to create a galaxy, some falls to the center and feeds the black hole there; it grows as its host galaxy does.

当这些物质聚在一起形成星系时，一些物质会落到星系中心，并在那里形成黑洞：它像它的宿主星系一样成长。

They asked: if we see these four images of the supernova in one image of its host galaxy, when would the supernova appear in these other two images of the host galaxy?

既然我们在这个图像里看到了超新星爆发，那另外的两个图像里又该是什么时候出现超新星爆发呢？