Galaxy Collision and Activation of Galactic Nuclei

研究了星系碰撞假说作为活动星系核（如塞弗特星系和类星体）的合理机制。根据这种假设，碰撞星系或目标星系中的气体可以吸积到星系中心的黑洞上，从而激活它们的原子核。我们研究了40多个环形星系的核光谱，这些星系被认为是通过星系碰撞形成的。样本星系取自Arp-Madore的特殊星系目录（1989）。利用本基金购买的SUN工作站的IRAF系统对CTIO 1.5m望远镜卡塞格伦光谱仪采集的CCD数据进行了缩减。我们的初步结果如下。1)大多数环状星系都有很强的发射谱线。2)它们大多是星暴型或LINER型，只有3个核是Seyfert 2型。3)在目前的样本中，我们没有发现新的Seyfert 1型环状星系，因此不能证实上述关于环状星系的猜想。4)通过与IRAS点交叉检查其光学位置。来源目录，大多数环状星系被发现是强IRAS源。5)这些结果可能意味着这种类型的星系碰撞，即星系垂直穿透目标星系的圆盘，可能对核馈入效率不高。今年计划进行进一步观察。

A galaxy collision hypothesis was examined as a plausible mechanism of active galactic nuclei, e. g., Seyfert galaxies and quasars. According to this senario, gas in colliding or target galaxies can accrete onto central black holes in galaxies, and so activate their nuclei.We studied nuclear spectra of more than 40 ring galaxies which are believed to have formed through galaxy collisions. Sample galaxies were taken from the Arp-Madore's Catalogue of Peculiar Galaxies (1989). CCD data, taken with the Cassegrain spectrograph of the 1.5m telescope-at CTIO, were reduced with IRAF system on SUN work station, which was purchased with the present grant. Our preliminary results are given bellow.1) Most of ring galaxies show strong emission lines.2) They are mostly star burst type or LINER, and only three nuclei are found to be Seyfert 2 type.3) Among the present sample, we found no new ring galaxies of Seyfert 1 type, and so cannot confirm the above conjecture for the case of ring galaxies.4) By cross checking their optical positions with IRAS Point. Source Catalog, most of ring galaxies are found to be strong IRAS sources.5) These results may imply that this type of galaxy collisions, i. e., a vertical penetration of a galaxy through a disk of a target galaxy, may not be efficient for nuclear feeding.Further observations are scheduled in this year.