Spatially Resolved Galactic Wind in Lensed Galaxy RCSGA 032727-132609
Spatially Resolved Galactic Wind in Lensed Galaxy RCSGA 032727-132609
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透镜星系中的空间分辨银河风 RCSGA 032727-132609
DOI：
10.1093/mnras/stw449
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发表时间：
2016
影响因子：
4.8
通讯作者：
E. Wuyts
中科院分区：
文献类型：
--
作者：
R. Bordoloi;J. Rigby;J. Tumlinson;M. Bayliss;K. Sharon;M. Gladders;E. Wuyts
在z=1.70的引力透镜恒星形成星系中，我们沿着四条视线探测流出气体的空间分布，视线间隔高达6kpc。用镁离子和铁离子的发射和吸收作为示踪剂，我们发现恒星形成的团块正在以-170到-250公里/秒的速度驱动银河系外流。镁离子发射的速度相对于星系的系统速度红移，这与后向散射是一致的。相比之下，FeII荧光发射线要么略有蓝移，要么处于星系的系统速度。综上所述，MGII和FeII发射的速度结构与星系风中散射产生的速度结构是一致的。假定喷出气体为薄壳几何结构，这些喷发的质量估计很大(>；30-50$\rm{M_(-1)yr^-1}}$)，质量负载因子是恒星形成速率的数倍。几乎20%到50%的蓝移吸收可能逃脱了星系的引力势。在这个星系中，流出是“局部来源”的，也就是说，在每条视线上的流出的性质是由最近的恒星形成团的性质决定的；风对星系来说并不是全球性的。该天体单个恒星形成结中流出的质量流出速率和动量通量与局部宇宙中的星爆星系相当。
We probe the spatial distribution of outflowing gas along four lines of sight separated by up to 6 kpc in a gravitationally-lensed star-forming galaxy at z=1.70. Using MgII and FeII emission and absorption as tracers, we find that the clumps of star formation are driving galactic outflows with velocities of -170 to -250 km/sec. The velocities of MgII emission are redshifted with respect to the systemic velocities of the galaxy, consistent with being back-scattered. By contrast, the FeII fluorescent emission lines are either slightly blueshifted or at the systemic velocity of the galaxy. Taken together, the velocity structure of the MgII and FeII emission is consistent with arising through scattering in galactic winds. Assuming a thin shell geometry for the out owing gas, the estimated masses carried out by these outfows are large (> 30 - 50 $\rm{M_{\odot} yr^{-1}}$), with mass loading factors several times the star-formation rate. Almost 20% to 50% of the blueshifted absorption probably escapes the gravitational potential of the galaxy. In this galaxy, the outflow is "locally sourced", that is, the properties of the outflow in each line of sight are dominated by the properties of the nearest clump of star formation; the wind is not global to the galaxy. The mass outflow rates and the momentum flux carried out by outflows in individual star forming knots of this object are comparable to that of starburst galaxies in the local Universe.