narrow line Seyfert 1 galaxy窄线赛弗特1星系
narrow line seyfert galaxy窄线赛弗特1星系
seyfert galaxy individual ngc塞佛特星系
Seyfert Galaxy NGC荷包蛋星系
N（名词） any of a class of spiral galaxies having a very bright nucleus, possibly corresponding to an active period in the lives of all spiral galaxies 赛弗特星系