标题： 约z=5的两个引力透镜化Lyman-α发射星系 显示英文标题

标题： Two Lensed Lyman-alpha Emitting Galaxies at z~5

摘要： We present observations of two strongly lensed $z\sim5$ Lyman-$\alpha$ Emitting (LAE) galaxies that were discovered in the Sloan Giant Arcs Survey (SGAS). We identify the two sources as SGAS J091541+382655, at $z=5.200$, and SGAS J134331+415455 at $z=4.994$. 我们测量了它们在AB magnitude系统下的$(i,z)=(23.34\pm0.09,23.29\pm0.13$魔格和$(i,z)=(23.78\pm0.18,24.24^{+0.18}_{-0.16}$魔格的亮度，并分别测量了SGAS J091541+382655和SGAS J134331+415455的Lyman-$\alpha$发射线的rest-frame等效宽度，对应的红移分别为$25.3\pm4.1$\AA 和$135.6\pm20.3$\AA 。每个源都被前景的大质量星系团强烈透镜化，由于引力透镜效应产生的增益已经从前景透镜势的强透镜建模中恢复出来。 我们利用放大率来计算两个源的固有、未透镜的 Lyman-$\alpha$和 UV 连续谱光度，以及由此推断出的恒星形成率 (SFR)。 我们发现SGAS J091541+382655和SGAS J134341+415455分别是具有（L$_{Ly-\alpha}$, L$_{UV})\leq(0.6$L$_{Ly-\alpha}^{*}, 2$L$_{UV}^{*}$）和（L$_{Ly-\alpha}$, L$_{UV})=(0.5$L$_{Ly-\alpha}^{*}, 0.9$L$_{UV}^{*}$）的星系。 将两星系的谱能量分布（SED）与恒星群体模型对比得出各星系年轻恒星的质量估计：我们报告SGAS J091531+382655的质量上限为 M$_{stars} \leq 7.9^{+3.7}_{-2.5} \times 10^{7}$ M$_{\sun} h_{0.7}^{-1}$，而SGAS J134331+415455的可能质量范围为$2\times10^{8}$ M$_{\sun} h_{0.7}^{-1} <$ M$_{stars} < 6\times10^{9}$ M$_{\sun} h_{0.7}^{-1}$。 显示英文摘要

摘要： We present observations of two strongly lensed $z\sim5$ Lyman-$\alpha$ Emitting (LAE) galaxies that were discovered in the Sloan Giant Arcs Survey (SGAS). We identify the two sources as SGAS J091541+382655, at $z=5.200$, and SGAS J134331+415455 at $z=4.994$. We measure their AB magnitudes at $(i,z)=(23.34\pm0.09,23.29\pm0.13$) mags and $(i,z)=(23.78\pm0.18,24.24^{+0.18}_{-0.16}$) mags, and the rest-frame equivalent widths of the Lyman-$\alpha$ emission at $25.3\pm4.1$\AA~and $135.6\pm20.3$\AA~for SGAS J091541+382655 and SGAS J134331+415455, respectively. Each source is strongly lensed by a massive galaxy cluster in the foreground, and the magnifications due to gravitational lensing are recovered from strong lens modeling of the foreground lensing potentials. We use the magnification to calculate the intrinsic, unlensed Lyman-$\alpha$ and UV continuum luminosities for both sources, as well as the implied star formation rates (SFR). We find SGAS J091541+382655 and SGAS J134341+415455 to be galaxies with (L$_{Ly-\alpha}$, L$_{UV})\leq(0.6$L$_{Ly-\alpha}^{*}, 2$L$_{UV}^{*}$) and (L$_{Ly-\alpha}$, L$_{UV})=(0.5$L$_{Ly-\alpha}^{*}, 0.9$L$_{UV}^{*}$), respectively. Comparison of the spectral energy distributions (SEDs) of both sources against stellar population models produces estimates of the mass in young stars in each galaxy: we report an upper limit of M$_{stars} \leq 7.9^{+3.7}_{-2.5} \times 10^{7}$ M$_{\sun} h_{0.7}^{-1}$ for SGAS J091531+382655, and a range of viable masses for SGAS J134331+415455 of $2\times10^{8}$ M$_{\sun} h_{0.7}^{-1} <$ M$_{stars} < 6\times10^{9}$ M$_{\sun} h_{0.7}^{-1}$.