z ∼ 2.5–3 Ionizers in the GOODS-N Field
z ∼ 2.5–3 Ionizers in the GOODS-N Field
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DOI：
10.3847/1538-4357/aacef8
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发表时间：
2018-06
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影响因子：
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通讯作者：
L. Jones;A. Barger;A. Barger;L. Cowie;P. Oesch;E. Hu;A. Songaila;R. P. Naidu
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文献类型：
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作者：
L. Jones;A. Barger;A. Barger;L. Cowie;P. Oesch;E. Hu;A. Songaila;R. P. Naidu
我们使用哈勃深紫外探测的F275W成像和哈勃太空望远镜/WFC3的G280格栅光谱，以及Keck/Deimos的新的和存档的光谱，在z∼2.5-3的Goods-N场中寻找候选的电离源。在UV成像区，我们的UV选择的源的光谱识别完成了99%，我们在z∼3发现了6个潜在的电离星系或活动星系核(AGN)。到目前为止，其中最亮的是a z=2.583 AGN，它完全控制了该区域的电离通量根据我们的光谱数据，我们发现有四个候选星系在z−0.5-0.7时受到前景星系的污染。在ERG S−1 Hz−1 MPC−3，剩余候选星系对电离背景的贡献远低于在z∼2.5-3电离星际介质所需的通量，这与先前的观测结果一致，表明在这些红移时，活动星系核提供了大部分电离背景。
We use deep F275W imaging from the Hubble Deep UV Legacy Survey (HDUV) and G280 grism spectroscopy from the Hubble Space Telescope/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 six potential ionizing galaxies or active galactic nuclei (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 erg s−1 Hz−1 Mpc−3. Based on our spectroscopic data, we find that four candidates are contaminated by foreground galaxies at z ∼ 0.5–0.7. At 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 that AGNs provide the bulk of the ionizing background at these redshifts.