标题： ATCA HI观测奇异星系IC2554 显示英文标题

标题： ATCA HI Observations of the Peculiar Galaxy IC2554

摘要： ATCA HI和射电连续谱对特殊南天星系IC2554及其周围区域的观测揭示了相互作用星系团的典型特征。我们在IC2554和椭圆星系NGC3136B之间探测到了一个大的HI云。IC2554本身的气体动力学，有时被描述为碰撞对，出人意料地规则，而NGC3136B则未被探测到。从IC2554延伸出的一个大的弧形喷射物形成了HI云，其大小约为30 kpc，比IC2554本身更大。IC2554系统的总HI质量约为2×10^9 Msun，其中三分之一位于HI云中。可能是IC2554和NGC3136B之间的潮汐相互作用导致了这个壮观的HI云，但IC2554作为合并残余的可能性也进行了讨论。我们还在附近的星系ESO092-G009和RKK1959中探测到了HI气体以及一个相关的HI云，ATCA J1006-6710。它们的总HI质量约为4.6×10^8 Msun。另一个新的HI源ATCA J1007-6659，其HI质量仅为约2.2×10^7 Msun，大致位于IC2554和ESO092-G009之间，并对应于一个正面朝向的低表面亮度矮星系。恒星形成仅在星系IC2554中明显，其速率为约4 Msun/yr。 显示英文摘要

摘要： ATCA HI and radio continuum observations of the peculiar southern galaxy IC2554 and its surroundings reveal typical signatures of an interacting galaxy group. We detected a large HI cloud between IC2554 and the elliptical galaxy NGC3136B. The gas dynamics in IC2554 itself, which is sometimes described as a colliding pair, are surprisingly regular, whereas NGC3136B was not detected. The HI cloud, which emerges from IC2554 as a large arc-shaped plume, has a size of about 30 kpc, larger than that of IC2554. The total HI mass of the IC2554 system is about 2 x 10^9 Msun, a third of which resides in the HI cloud. It is possible that tidal interaction between IC2554 and NGC3136B caused this spectacular HI cloud, but the possibility of IC2554 being a merger remnant is also discussed. We also detected HI gas in the nearby galaxies ESO092-G009 and RKK1959 as well as an associated HI cloud, ATCA J1006-6710. Together they have an HI mass of about 4.6 x 10^8 Msun. Another new HI source, ATCA J1007-6659, with an HI mass of only about 2.2 x 10^7 Msun was detected roughly between IC2554 and ESO092-G009 and corresponds to a face-on low surface brightness dwarf galaxy. Star formation is evident only in the galaxy IC2554 with a rate of about 4 Msun/yr.