标题： 在明亮红外合并体阿普299中的一个180千秒差距的潮汐尾 显示英文标题

标题： A 180 Kpc Tidal Tail in the Luminous Infrared Merger Arp 299

摘要： 我们展示了Arp 299（= NGC 3690 + IC 694）的VLA HI观测和UH88深光学B-和R波段观测。这些数据揭示了一个富含气体、光学微弱的潮汐尾，长度超过180 kpc。这个潮汐特征的大小表明合并体有一个较老的相互作用年龄（约750 Myr，自第一次近星点以来），目前正处于一个非常年轻的恒星爆发（约20 Myr）。观测揭示了潮汐尾内一个最显著的结构：它似乎由两条平行的纤维组成，相距约20 kpc。其中一条纤维富含气体，几乎没有恒星光，而另一条则气体贫乏。我们认为这种分叉是由于其中一个前体星系的扭曲盘所致。潮汐HI的数量和运动学表明，Arp 299是750 Myr前发生的逆行Sab-Sb星系（IC 694）和顺行Sbc-Sc星系（NGC 3690）碰撞的结果，并将在约60 Myr内合并成一个单一物体。我们认为该系统目前的红外明亮阶段部分归因于IC 694的逆行旋转。最后，我们讨论了尾部中明显缺乏潮汐矮星系的现象。 显示英文摘要

摘要： We present VLA HI observations and UH88 deep optical B- and R-band observations of the IR luminous merger Arp 299 (= NGC 3690 + IC 694). These data reveal a gas-rich, optically faint tidal tail with a length of over 180 kpc. The size of this tidal feature necessitates an old interaction age for the merger (~750 Myr since first periapse), which is currently experiencing a very young star burst (~20 Myr). The observations reveal a most remarkable structure within the tidal tail: it appears to be composed of two parallel filaments separated by ~20 kpc. One of the filaments is gas rich with little if any starlight, while the other is gas poor. We believe that this bifurcation results from a warped disk in one of the progenitors. The quantities and kinematics of the tidal HI suggest that Arp 299 results from the collision of a retrograde Sab-Sb galaxy (IC 694) and a prograde Sbc-Sc galaxy (NGC 3690) that occurred 750 Myr ago and which will merge into a single object in ~60 Myr. We suggest that the present IR luminous phase in this system is due in part to the retrograde spin of IC 694. Finally, we discuss the apparent lack of tidal dwarf galaxies within the tail.