恒星形成区NGC7538中的分子氢发射(英文)

MOLECULAR HYDROGEN EMISSION IN STAR FORMING REGION NGC7538

报告在NGC7538 中利用H2(2 .12 μm) 发射线观测新发现的两个喷流和18 个近红外HH 天体.在IRS13 星云中观测到了强H2 发射壳层结构环绕在星云的北边.星云中红外源的UV 辐射场和外流活动都可能导致这一H2 发射.在IRS13 星云的南边和东边探测到了5 个H2 knots.在IRS1 南边发现的H2 喷流暗示该区域有一个南北向的外流.在IRS11 星团的周围发现了9 个H2 knots.在西北东南方向和东北方向上各有一对H2 knots 与IRS11成直线排列.另外两个纤维状H2 knots 似乎由IRS11 在东北方向上发射出来.在IRS11 星团的东南观测到3 个H2 knots,其中的两个似是一条弯曲H2 结构上的亮节点.在邻近IRS9 的西边发现了两个明亮的H2 团块,它们的排列与IRS9 IRN1 星云的西南走向一致.在IRS9东南方向探测到了一个高准直的团块状喷流,与IRS9 星云的南向分支IRN 2 走向一致.在IRS9 以北～1′处还发现了一个不可分辨的H2 knot 和弥漫的H2 发射.分析发现许多H2 发射在形态上与分子线毫米观测的线翼发射的空间特征相一致.观测结果证明在3 个恒星形成区,即IRS13 ,IRS9 和IRS11 。

The discovery of two jets and 18 HH like objects in H 2(2.12 μm) emission in the star forming region NGC7538 is reported in this paper. Strong H 2 emission in a shell structure is observed to surround the northern IRS 1 3 nebula, and both the UV radiation field and outflow activity from the infrared sources could be responsible for the H 2 emission. Five H 2 knots are detected to the south and east of the IRS 1 3 nebula. An H 2 jet feature emanating to the south of IRS 1 implies a N S outflow in the region. Nine H 2 knots are found around the IRS 11 cluster. Two pairs of H 2 knots lie in good alignment with IRS 11 in the NW SE and to the NE direction. Two H 2 knots with filamentary structure appear to emanate from IRS 11 in the NW direction. There are three H 2 knots to the SE of IRS 11 cluster, and two of them seem to be bright knots of a curved H 2 structure. Two bright H 2 clumps are revealed to the west of IRS 9, consistent with the SW extension of the IRS 9 nebula, i.e. IRN 1. A highly collimated clumpy jet is detected to the SE of IRS 9, and this is consistent with the nebular extension to the south, IRN 2. An unresolved H 2 knot associated with diffuse H 2 emission is also found ～1′ north of IRS 9. Morphologically, many of the H 2 features are found to be consistent with enhanced molecular wing emission observed in the mm waves. The results show that multiple outflows with very different directions are present in the three star forming regions, IRS 1 3, IRS 9 and IRS 11.