标题： 高红移莱曼-α发射体的窄带检测特性 显示英文标题

标题： On the narrowband detection properties of high-redshift Lyman-alpha emitters

摘要： 正在开展或计划进行大量调查，旨在利用莱曼-α发射线作为探测遥远宇宙的探针。 我们研究此类高红移Lya研究的可靠性以及基于这些研究的结论的有效性。 我们检查是否可以从窄带成像调查中可靠地估计Lya流量（F_Lya）和等效宽度（W_Lya），以及是否存在任何观测偏差。 我们开发了软件，通过采用各种典型的观测技术来模拟遥远宇宙中合成LAE的观测线和连续谱特性。 该软件被用来研究检测到的F_Lya和W_Lya如何随着宿主星系或IGM的特性变化：内部尘埃变红；中间的Lya吸收系统；以及潜在恒星种群的存在。 所研究的任何技术都不容易受到潜在恒星种群或星云气体贡献的影响。 我们发现，使用Lya红端的一个离线滤光片的技术会导致W_Lya测量结果高度不准确。 采用两个离线滤光片来估计Lya处的连续谱是一个改进，但在考虑尘埃消光时仍然不可靠。 使用相同中心波长的单个窄带和宽带滤光片的技术不受内部尘埃的影响，但IGM的Lya吸收可能导致W_Lya被高估达2倍；在z=6时，中位W_Lya被高估约25%。 最可靠的方法是一种SED拟合技术，该技术从合成模型中拟合E(B-V)和爆发年龄——需要能采样紫外连续谱斜率、2175AA尘埃特征和4000AA不连续性的宽波段观测。 我们还注意到一种红移相关的不完整性，这是由于接近目标LAE的DLA系统引起的，在z=6时约为10%。 显示英文摘要

摘要： Numerous surveys are underway or planned that aim to exploit the Lyman-alpha emission line as a probe of the distant universe. We investigate the reliability of such high-z Lya studies and the validity of the conclusions that are based upon them. We examine whether reliable Lya fluxes (F_Lya) and equivalent widths (W_Lya) can be estimated from narrowband imaging surveys and whether any observational biases may be present. We have developed software to simulate the observed line and continuum properties of synthetic LAEs in the distant universe by adopting various typical observational techniques. This was used to investigate how detected F_Lya and W_Lya vary with properties of the host or IGM: internal dust reddening; intervening Lya absorption systems; the presence of underlying stellar populations. None of the techniques studied are greatly susceptible to underlying stellar populations or the contribution of nebular gas. We find that techniques that use one off-line filter on the red side of Lya result in highly inaccurate measurements of W_Lya. Adopting two off-line filters to estimate continuum at Lya is an improvement but is still unreliable when dust extinction is considered. Techniques that employ single narrow- and broad-band filters with the same central wavelength are not susceptible to internal dust, but IGM Lya absorption can cause W_Lya to be overestimated by factors of up to 2: at z=6, the median W_Lya is overestimated by ~25%. The most robust approach is a SED fitting technique that fits E(B-V) and burst-age from synthetic models - broadband observations are needed that sample the UV continuum slope, 2175AA dust feature, and the 4000AA discontinuity. We also notice a redshift-dependent incompleteness that results from DLA systems close to the target LAEs, amounting to ~10% at z=6.