The Faint End of the QSO Luminosity Function at z = 3
The Faint End of the QSO Luminosity Function at z = 3
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z = 3 处 QSO 光度函数的微弱末端
DOI：
10.1086/381727
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
A. Shapley
中科院分区：
文献类型：
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作者：
M. Hunt;C. Steidel;K. Adelberger;A. Shapley
我们提出了QSO亮度函数在z = 3处的微弱末端的第一次测量。使用多色选择标准（莱曼断裂技术）和光谱跟踪，在17个总计0.43°2的油田中发现了qso，范围从M1450 = -21到M1450 = -27。我们发现亮度函数的暗端斜率为βl = 1.24±0.07 （Φ∝L），比低红移时测得的βl = 1.64±0.18更平坦。在相同的红移下，z = 3 qso的紫外亮度仅为以前估计的50%，仅为Lyman破碎星系的8%。假设弱量子粒子的电离光子能像明亮量子粒子那样成功地逃离宿主星系，我们估计量子粒子对电离通量的贡献在z ~ 3， J912为2.4 × 10-22 ergs -1 cm-2 Hz-1。这个估计，我们认为是上限，与基于Lyα森林“接近效应”的J912的粗略估计保持一致。
We present the first measurement of the faint end of the QSO luminosity function at z = 3. The QSOs, which range from M1450 = -21 to M1450 = -27, were discovered in 17 fields totaling 0.43 deg 2 using multicolor selection criteria (the Lyman break technique) and spectroscopic follow-up. We find that the faint-end slope of the luminosity function is βl = 1.24 ± 0.07 (Φ ∝ L), flatter than the value of βl = 1.64 ± 0.18 measured at lower redshift. The integrated rest 1450 Å UV luminosity of z = 3 QSOs is only 50% of most previous estimates and only ≃8% of that produced by Lyman break galaxies at the same redshifts. Assuming that ionizing photons from faint QSOs are as successful in escaping their host galaxies as bright QSOs, we estimate the total contribution of QSOs to the ionizing flux J912 at z ~ 3, J912 ≃ 2.4 × 10-22 ergs s-1 cm-2 Hz-1. This estimate, which we regard as an upper limit, remains consistent with rough estimates of J912 based on the Lyα forest "proximity effect."