THE PROPERTIES AND PREVALENCE OF GALACTIC OUTFLOWS AT z ∼ 1 IN THE EXTENDED GROTH STRIP
THE PROPERTIES AND PREVALENCE OF GALACTIC OUTFLOWS AT z ∼ 1 IN THE EXTENDED GROTH STRIP
复制标题
扩展格罗斯带中 z 〜 1 处星系外流的性质和普遍性
DOI：
10.1088/0004-637x/758/2/135
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
K. Noeske
中科院分区：
文献类型：
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作者：
K. Kornei;A. Shapley;C. Martin;A. Coil;J. Lotz;D. Schiminovich;K. Bundy;K. Noeske
我们研究了扩展格罗斯带 z ∼ 1 处 72 个恒星形成星系中的银河尺度外流风。从 DEEP2 巡天中选择星系，并获得了后续 LRIS 光谱，涵盖静止帧紫外中的 Si ii、C iv、Fe ii、Mg ii 和 Mg i 谱线。使用星系演化探测器 (GALEX)、哈勃太空望远镜 (HST) 和可用于扩展格罗斯带的斯皮策成像，我们以每个物体为基础检查星系，以便更好地了解 z ∼ 1 处星系外流的普遍性以及经历外流的物体的恒星形成和结构特性。从 Fe ii 星际吸收线的质心测量的气体速度被发现跨越区间 [−217, +155] km s−1。我们发现~40% (10%) 的样品在 1σ (3σ) 水平上表现出蓝移的 Fe ii 谱线。我们还使用 Fe ii 和 Mg ii 线的剖面测量最大流出速度；我们发现 Mg ii 经常比 Fe ii 追踪更高速度的气体。使用从 HST 成像得出的定量形态参数，我们发现合并并不是驱动资本外流的先决条件。更多面对面的星系也显示出比高度倾斜的系统更强的风，这与垂直于星系盘发出的风的典型图像一致。鉴于块状星系形态，我们开发了一种新的物理驱动技术来估计与恒星形成相对应的区域。我们将这些面积测量值与 GALEX 衍生的恒星形成率 (SFR) 结合使用来计算 SFR 表面密度。至少 70% 的样本超过了 0.1 M☉ yr−1 kpc−2 的恒星形成率表面密度，这是驱动局部星暴中外流所需的阈值。同时，Fe ii 吸收中仅 40% 的流出检测分数为非球对称的流出几何形状提供了进一步的证据。我们看到流出速度和恒星形成率表面密度之间存在〜3σ趋势，但流出速度和恒星形成率之间没有显着趋势。需要更高分辨率的数据来测试流出速度与理论预测的恒星形成率和恒星形成率表面密度之间的比例关系。
We investigate galactic-scale outflowing winds in 72 star-forming galaxies at z ∼ 1 in the Extended Groth Strip. Galaxies were selected from the DEEP2 survey and follow-up LRIS spectroscopy was obtained covering Si ii, C iv, Fe ii, Mg ii, and Mg i lines in the rest-frame ultraviolet. Using Galaxy Evolution Explorer (GALEX), Hubble Space Telescope (HST), and Spitzer imaging available for the Extended Groth Strip, we examine galaxies on a per-object basis in order to better understand both the prevalence of galactic outflows at z ∼ 1 and the star-forming and structural properties of objects experiencing outflows. Gas velocities, measured from the centroids of Fe ii interstellar absorption lines, are found to span the interval [−217, +155] km s−1. We find that ∼40% (10%) of the sample exhibits blueshifted Fe ii lines at the 1σ (3σ) level. We also measure maximal outflow velocities using the profiles of the Fe ii and Mg ii lines; we find that Mg ii frequently traces higher velocity gas than Fe ii. Using quantitative morphological parameters derived from the HST imaging, we find that mergers are not a prerequisite for driving outflows. More face-on galaxies also show stronger winds than highly inclined systems, consistent with the canonical picture of winds emanating perpendicular to galactic disks. In light of clumpy galaxy morphologies, we develop a new physically motivated technique for estimating areas corresponding to star formation. We use these area measurements in tandem with GALEX-derived star formation rates (SFRs) to calculate SFR surface densities. At least 70% of the sample exceeds an SFR surface density of 0.1 M☉ yr−1 kpc−2, the threshold necessary for driving an outflow in local starbursts. At the same time, the outflow detection fraction of only 40% in Fe ii absorption provides further evidence for an outflow geometry that is not spherically symmetric. We see a ∼3σ trend between outflow velocity and SFR surface density, but no significant trend between outflow velocity and SFR. Higher resolution data are needed in order to test the scaling relations between outflow velocity and both SFR and SFR surface density predicted by theory.