论文标题
BDF在z = 7时在bdf恢复气泡中的两个明亮的$α$发射器的电离特性
The ionizing properties of two bright Ly$α$ emitters in the BDF reionized bubble at z=7
论文作者
论文摘要
我们在z = 7.012时研究了一对亮$α$发射星系BDF521和BDF2195的电离特性，以限制其对BDF“重新离子气泡”形成的贡献。我们从紫外线排放线（civ $λ1548$ doublet，heii $λ1640$，oiii] $λ1660$ doublet和ciii] $λ11909$ doublet）获得限制，从深vlt-xshooter观察中，将它们与其他高级对象相比，将它们与其他对象相比。我们将这些光谱信息与现场可用的光度法一起使用，以使用Spectro-Spotro-Pompotric拟合代码Beagle来限制两个对象的物理属性。我们没有在紫外线的预期位置检测到任何明显的排放，其中3 $σ$上限的EW $ \ lyssim $ 2-7 $ 2-7 AA REST框架。我们发现，基于Ly $α$和CIII] EWS之间的相关性，这两个对象的发射比预期的要低。 CIV和HEII排放的EW限制在$ \sim2-3σ$中排除了纯AGN模板，并且只有$ \ lyssim $ 40％AGN贡献的模型与观察值兼容。发现这两个对象相对年轻（$ \ sim $ 20-30 myrs）和金属贫困（$ \ lyssim 0.3 z _ {\ odot} $），其出色的质量为$ 10^9M _ {\ odot} $。它们的氢离子化光子的生产速率是日志（$ξ_{ion}^*$/hz erg $^{ - 1} $）= 25.02-25.26是一致的，与在高红色的星系中通常发现的价值一致，但比$ z> $ 7的ciii and/of z> $ 7 ciii and/of z Issive of/of zii twice and/of quii the twice and/ （$ \ simeq $ 25.6-25.7）。这两个BDF发射器没有高于平均电离能力高的证据，也无法通过自己的手段在现实的假设上通过对电离光子的逃生分数进行回报。 （简略）
We investigate the ionizing properties of the pair of bright Ly$α$ emitting galaxies BDF521 and BDF2195 at z=7.012 in order to constrain their contribution to the formation of the BDF "reionized bubble". We obtain constraints on UV emission lines (CIV$λ1548$ doublet, HeII$λ1640$, OIII]$λ1660$ doublet, and CIII]$λ1909$ doublet) from deep VLT-XSHOOTER observations and compare them to those available for other high-redshift objects, and to models with mixed stellar and AGN emission. We use this spectroscopic information together with the photometry available in the field to constrain the physical properties of the two objects using the spectro-photometric fitting code BEAGLE. We do not detect any significant emission at the expected position of UV lines, with 3$σ$ upper limits of EW$\lesssim$2-7 AA rest-frame. We find that the two objects have lower CIII] emission than expected on the basis of the correlation between the Ly$α$ and CIII] EWs. The EW limits on CIV and HeII emission exclude pure AGN templates at $\sim2-3σ$ significance, and only models with a $\lesssim$40% AGN contribution are compatible with the observations. The two objects are found to be relatively young ($\sim$20-30 Myrs) and metal-poor ($\lesssim 0.3 Z_{\odot}$) with stellar masses of a few $10^9M_{\odot}$. Their production rate of hydrogen ionizing photons per intrinsic UV luminosity is log($ξ_{ion}^*$/Hz erg$^{-1}$)=25.02-25.26, consistent with values typically found in high-redshift galaxies, but more than twice lower than values measured in $z>$7 galaxies with strong CIII] and/or optical line emission ($\simeq$25.6-25.7). The two BDF emitters have no evidence of higher than average ionizing capabilities and are not capable of reionizing their surroundings by their own means under realistic assumptions on the escape fraction of ionizing photons. (abridged)
