Boxy H alpha emission profiles in star-forming galaxies
Boxy H alpha emission profiles in star-forming galaxies
复制标题
恒星形成星系中的 Boxy Hα 发射剖面
DOI：
10.1093/mnras/stw942
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发表时间：
2016
影响因子：
4.8
通讯作者：
Jin Yifei
中科院分区：
文献类型：
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作者：
Chen Yan-Mei;Gu Qiu-Sheng;Tremonti Christy A.;Shi Yong;Jin Yifei
我们从斯隆数字天空勘测数据发布7中收集了一个盘状恒星形成星系的样本，研究了H$\α$发射线的结构，发现这个样本中有很大一部分包含方形的H$\α$谱线轮廓。这一比例依赖于星系的物理和几何参数：(1)它随单位面积的恒星形成率($\Sigma_{Rm SFR}$)和恒星质量($M_*$)单调增加，且这种趋势随着$M_*的增加而增强，从$M_*=10^{10}M_(ODOT)$时的$\sim$0%增加到$M_*=10^{11}M_(ODOT)$时的约50%；(2)正面系统的比例比边缘系统的小得多。它随着星系倾角的增加而增大，超过这个范围约为25%；(3)对于系统速度蓝移和红移两个速度分量可以很好模拟的源，这两个分量的速度差与恒星质量呈正相关，斜率类似于Tully-Fisher关系；(4)这两个分量的平均值在速度和幅度上都非常对称。上面列出的四个发现可以理解为具有KPC尺度的环状H$\α$发射区的旋转星系盘的自然结果。
We assemble a sample of disk star-forming galaxies from the Sloan Digital Sky Survey Data Release 7, studying the structure of H$\alpha$ emission lines, finding a large fraction of this sample contains boxy H$\alpha$ line profiles. This fraction depends on galaxy physical and geometric parameters in the following way: (1) it increases monotonically with star formation rate per unit area ($\Sigma_{\rm SFR}$), and stellar mass ($M_*$), with the trend being much stronger with $M_*$, from $\sim$0% at $M_*=10^{10}M_{\odot}$ to about 50% at $M_*=10^{11}M_\odot$; (2) the fraction is much smaller in face-on systems than in edge-on systems. It increases with galaxy inclination ($i$) while $i < 60\,^{\circ}$ and is roughly a constant of 25% beyond this range; (3) for the sources which can be modeled well with two velocity components, blueshifted and redshifted from the systemic velocity, these is a positive correlation between the velocity difference of these two components and the stellar mass, with a slope similar to the Tully-Fisher relation; (4) the two components are very symmetric in the mean, both in velocity and in amplitude. The four findings listed above can be understood as a natural result of a rotating galaxy disk with a kpc-scale ring-like H$\alpha$ emission region.