The Faint End of the Quasar Luminosity Function at z ∼ 5 from the Subaru Hyper Suprime-Cam Survey
The Faint End of the Quasar Luminosity Function at z ∼ 5 from the Subaru Hyper Suprime-Cam Survey
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DOI：
10.3847/1538-4357/abbe11
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发表时间：
2020-10
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通讯作者：
M. Niida;T. Nagao;H. Ikeda;M. Akiyama;Y. Matsuoka;W. He;K. Matsuoka;Y. Toba;M. Onoue;Masakazu A. R. Kobayashi;Y. Taniguchi;H. Furusawa;Y. Harikane;M. Imanishi;N. Kashikawa;T. Kawaguchi;Y. Komiyama;H. Shirakata;Y. Terashima;Y. Ueda
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作者：
M. Niida;T. Nagao;H. Ikeda;M. Akiyama;Y. Matsuoka;W. He;K. Matsuoka;Y. Toba;M. Onoue;Masakazu A. R. Kobayashi;Y. Taniguchi;H. Furusawa;Y. Harikane;M. Imanishi;N. Kashikawa;T. Kawaguchi;Y. Komiyama;H. Shirakata;Y. Terashima;Y. Ueda
我们提出的类星体的光度函数在z = 5来自光学宽视场调查数据的斯巴鲁战略计划（SSP）的一部分，与超Suprime-Cam（HSC）。在HSC-SSP巡天的宽层中，我们采用Lyman break方法，在24.1等以下选取了224个候选的低光度类星体。根据我们的候选和Sloan数字巡天（SDSS）光谱证实的类星体，我们导出了z = 24.1等的类星体光度函数，我们发现类星体的光度函数可以用双幂律模型来拟合，其突变星等为ma。低光度类星体的数密度较低，并且导出的暗端斜率，比以前的研究在z 105处的那些平坦。从HSC-SSP得到的类星体光度函数在4 ≤ z ≤ 6处的汇编表明，在这个红移范围内，突变星等和暗端斜率几乎没有红移演化，尽管以前的研究表明暗端斜率在更高的红移处变得更陡。低光度类星体的数密度从z 105到z 106比从z 104到z 105下降得更快。
We present the quasar luminosity function at z ∼ 5 derived from the optical wide-field survey data obtained as a part of the Subaru strategic program (SSP) with the Hyper Suprime-Cam (HSC). From a ∼81.8 deg2 area in the Wide layer of the HSC-SSP survey, we selected 224 candidates of low-luminosity quasars at z ∼ 5 by adopting the Lyman-break method down to i = 24.1 mag. Based on our candidates and spectroscopically confirmed quasars from the Sloan Digital Sky Survey (SDSS), we derived the quasar luminosity function at z ∼ 5, covering a wide luminosity range of −28.76 < M1450 < −22.32 mag. We found that the quasar luminosity function is fitted by a double power-law model with a break magnitude of mag. The inferred number density of low-luminosity quasars is lower, and the derived faint-end slope, , is flatter than those of previous studies at z ∼ 5. A compilation of the quasar luminosity function at 4 ≤ z ≤ 6 from the HSC-SSP suggests that there is little redshift evolution in the break magnitude and in the faint-end slope within this redshift range, although previous studies suggest that the faint-end slope becomes steeper at higher redshifts. The number density of low-luminosity quasars decreases more rapidly from z ∼ 5 to z ∼ 6 than from z ∼ 4 to z ∼ 5.