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arXiv 1207.5897astro-ph.CO
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z~2星系运动学的SINS/zC-SINF研究:外流性质

The SINS/zC-SINF survey of z~2 galaxy kinematics: Outflow properties

Sarah F. Newman, Reinhard Genzel, Natascha Forster-Schreiber, Kristin Shapiro Griffin, Chiara Mancini, Simon J. Lilly, Alvio Renzini, Nicolas Bouche, Andreas Bu… 展开作者

Sarah F. Newman, Reinhard Genzel, Natascha Forster-Schreiber, Kristin Shapiro Griffin, Chiara Mancini, Simon J. Lilly, Alvio Renzini, Nicolas Bouche, Andreas Burkert, Peter Buschkamp, C. Marcella Carollo, Giovanni Cresci, Ric Davies, Frank Eisenhauer, Shy Genel, Erin K. S. Hicks, Jaron Kurk, Dieter Lutz, Thorsten Naab, Yingjie Peng, Amiel Sternberg, Linda J. Tacconi, Daniela Vergani, Stijn Wuyts, Gianni Zamorani

摘要:

基于30个z \sim 2恒星形成星系(SFG)的SINFONI Ha、[NII]和[SII] AO数据,我们发现Ha宽通量分数与星系的恒星形成面密度有很强的相关性,强外流的明显阈值出现在1 Msun yr^-1 kpc^-2。在此阈值以上,我们发现,与低质量SFG相比,logm_ \ast >10的SFG具有相似或可能更大的风质量负载因子(eta = Mdotout/SFR)和更快的流出速度。这一趋势表明,z \sim 2处的大部分流出气体可能来自高质量SFG,z \sim 2质量-金属丰度关系更多地是由星系气藏中富集气体的稀释而不是流出的效率驱动的。质量负载因子也与SFR和倾角相关,因此更多的恒星形成和面对星系发射更强大的外流。对于星系有证据表明,强烈的外流,我们发现,广泛的发射空间扩展到至少半光半径(\sim几千秒差距)。我们建议,所观察到的强外流和所观察到的这些风的质量负载的阈值可以解释一个简单的模型,其中突破风是由压力平衡在磁盘。利用宽组分和窄组分中[SII]双重态的比值,我们发现流出气体的密度为\sim 10-100 cm^-3,明显小于恒星形成气体的密度(600 cm^-3)。

英文摘要:

Based on SINFONI Ha, [NII] and [SII] AO data of 30 z \sim 2 star-forming galaxies (SFGs) from the SINS and zcSINF surveys, we find a strong correlation of the Ha broad flux fraction with the star formation surface density of the galaxy, with an apparent threshold for strong outflows occurring at 1 Msun yr^-1 kpc^-2. Above this threshold, we find that SFGs with logm_\ast>10 have similar or perhaps greater wind mass loading factors (eta = Mdotout/SFR) and faster outflow velocities than lower mass SFGs. This trend suggests that the majority of outflowing gas at z \sim 2 may derive from high-mass SFGs, and that the z \sim 2 mass-metallicity relation is driven more by dilution of enriched gas in the galaxy gas reservoir than by the efficiency of outflows. The mass loading factor is also correlated with the SFR and inclination, such that more star-forming and face-on galaxies launch more powerful outflows. For galaxies that have evidence for strong outflows, we find that the broad emission is spatially extended to at least the half-light radius (\sim a few kpc). We propose that the observed threshold for strong outflows and the observed mass loading of these winds can be explained by a simple model wherein break-out of winds is governed by pressure balance in the disk. Using the ratio of the [SII] doublet in a broad and narrow component, we find that outflowing gas has a density of \sim10-100 cm^-3, significantly less than that of the star forming gas (600 cm^-3).

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