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arXiv 1806.08798astro-ph.GA
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z ~ 2.5 - 3 GOODS-N场中的电离子

z ~ 2.5 - 3 Ionizers in the GOODS-N Field

L. H. Jones, A. J. Barger, L. L. Cowie, P. A. Oesch, E. M. Hu, A. Songaila, R. P. Naidu

摘要:

我们使用来自$Hubble$深紫外遗产调查(HDUV)的深F275 W成像和来自$HST$ /WFC 3的G280棱镜光谱,以及来自Keck/DEIMOS的新的和存档的光谱,在z ~ 2.5 - 3的GOODS-N场中搜索候选电离源。光谱识别我们的紫外选择源是99%完成的F275 W = 25.5的区域的紫外成像,我们确定6个潜在的电离星系或活动星系在z ~ 3。到目前为止,其中最亮的是z = 2.583的活动星系核,它完全主导了该区域的电离通量,在$912~ Å$处的比电离体积发射率为$ε_{912}$ = $8.3^{27}_{1.4} \times 10^{24}$ erg s $^{-1}$ Hz $^{-1}$ Mpc $^{-3}$。根据我们的光谱数据,我们发现四个候选人被污染的前景星系在z ~ 0.5 - 0.7。当$ε_{912}$ = $2.2^{7.2}_{0.4} \times 10^{23}$ erg s $^{-1}$ Hz $^{-1}$ Mpc $^{-3}$时,剩余的候选星系对电离背景的贡献远低于在z ~ 2.5 - 3处覆盖星系际介质所需的通量,这与以前的观测结果一致,即活动星系核提供了这些红移的大部分电离背景。

英文摘要:

We use deep F275W imaging from the $Hubble$ Deep UV Legacy Survey (HDUV) and G280 grism spectroscopy from $HST$/WFC3, along with new and archival optical spectra from Keck/DEIMOS, to search for candidate ionizing sources in the GOODS-N field at z ~ 2.5 - 3. Spectroscopic identification of our UV-selected sources are 99% complete to F275W = 25.5 in the region of the UV imaging, and we identify 6 potential ionizing galaxies or AGNs at z ~ 3. By far the brightest of these is a z = 2.583 AGN that totally dominates the ionizing flux in the region, with a specific ionizing volume emissivity at $912~ Å$ of $ε_{912}$ = $8.3^{27}_{1.4} \times 10^{24}$ erg s$^{-1}$ Hz$^{-1}$ Mpc$^{-3}$. Based on our spectroscopic data, we find four candidates are contaminated by foreground galaxies at z ~ 0.5 - 0.7. At $ε_{912}$ = $2.2^{7.2}_{0.4} \times 10^{23}$ erg s$^{-1}$ Hz$^{-1}$ Mpc$^{-3}$, the remaining candidate galaxy's contribution to the ionizing background lies well below the flux required to ionize the intergalactic medium at z ~ 2.5 - 3, consistent with previous observations that show AGNs provide the bulk of the ionizing background at these redshifts.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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