论文标题
观察到的矮星系的Lyman Alpha EW分布在Z〜2
The Origin of the Observed Lyman alpha EW Distribution of Dwarf Galaxies at z~2
论文作者
论文摘要
我们提供了一个休息的静脉联，以$ z \ sim 2 $观察到的32个镜头星系的样品与关节keck/lris rest-uv一起观察到，库克/mosfire/mosfire rest-actictical spactra clusters abell 1689，Macs J0717和Macs J1149。该样本朝观察到的最微弱的UV光度（$ -19 \ le {\ rm m _ {\ rm UV}}} \ le -17 $）。识别为ly $α$ emitters的矮星系的分数（$ \ rm ew \ ge 20 \ \ oftset {\ lower.5em \ circ} {\ mathrm {a}} $）是$ {\ rm x _ {\ rm x _ {\ rm lae}}我们使用Balmer系列和紫外线连续体来估计固有的EW，从而使我们能够区分电离光谱和LY $α$逃逸分数对观察到的EW分布的影响。 fainter星系（$ \ rm m _ {\ rm UV}> -19 $）显示出比较亮的星系更大的内在EWS和逃生分数。仅具有内在EWS的星系超过40 $ \ \ oftset {\ lower.5em \ circ} {\ mathrm {a}} $的逃生分数大于0.05。我们发现逃生分数与$ \ rm A_V $以及紫外频谱斜率之间的反相关。我们样本中的体积逃脱分数为$ f _ {\ rm esc}^{\ rmlyα} = 4.59^{+2.0} _ { - 1.4} \％$，与文献中其他地方的测量值一致。大约一半的集成$α$光度密度来自带有$ {\ rm ew} _ {\ rm obs}> 20 \ \ oftset {\ lower.5em \ circ} {\ mathrm {a a}} $的星系。
We present a rest-UV selected sample of 32 lensed galaxies at $z\sim 2$ observed with joint Keck/LRIS rest-UV and Keck/MOSFIRE rest-optical spectra behind the clusters Abell 1689, MACS J0717, and MACS J1149. The sample pushes towards the faintest UV luminosities observed ($-19 \le {\rm M_{\rm UV}} \le -17$) at this redshift. The fraction of dwarf galaxies identified as Ly$α$ emitters ($\rm EW \ge 20\ \overset{\lower.5em\circ}{\mathrm{A}}$) is ${\rm X_{\rm LAE}}=25^{+15}_{-10}\%$. We use the Balmer lines and UV continuum to estimate the intrinsic EW allowing us to distinguish the effects of the ionizing spectra and Ly$α$ escape fraction on the observed EW distribution. Fainter galaxies ($\rm M_{\rm UV} > -19$) show larger intrinsic EWs and escape fractions than brighter galaxies. Only galaxies with intrinsic EWs greater than 40$\ \overset{\lower.5em\circ}{\mathrm{A}}$ have escape fractions larger than 0.05. We find an anti-correlation between the escape fraction and $\rm A_V$ as well as UV spectral slope. The volumetric escape fraction of our sample is $f_{\rm esc}^{\rm Lyα} = 4.59^{+2.0}_{-1.4}\%$ in agreement with measurements found elsewhere in the literature. About half of the total integrated Ly$α$ luminosity density comes from galaxies with ${\rm EW}_{\rm obs}>20\ \overset{\lower.5em\circ}{\mathrm{A}}$.
