论文标题
在类星体的大光谱调查中检测Z> 3的中性氢
Detecting neutral hydrogen at z > 3 in large spectroscopic surveys of quasars
论文作者
论文摘要
我们提出了基于随机森林分类器的管道，用于鉴定中性氢的高柱密度云（即莱曼极限系统，LLSS，LLSS）在Z> 3 Quasars的大光谱范围内吸收。 We test the performance of this method on mock quasar spectra that reproduce the expected data quality of the Dark Energy Spectroscopic Instrument (DESI) and the WHT Enhanced Area Velocity Explorer (WEAVE) surveys, finding >90% completeness and purity for N(HI)> 10^17.2 cm^-2 LLSs against quasars of g < 23 mag at z~3.5-3.7.训练并应用了我们的方法在Sloan数字天空调查中的Z〜3.5-4.0上的10,000个类星体光谱上（数据发行16），我们在Z〜3.1-4.0之间识别〜6600 llss> 10^17.5 cm^-2，其完整性和纯度的完整性和纯度为> 90％> 90％> 90％> 90％。使用此样本，我们测量z = [3.3,3.6]时的每单位红移的LLSS每单位红移为2.32 +/- 0.08。我们还提出了关于随机森林的性能，以测量LLS红移和HI色谱柱密度，以及鉴定广泛的吸收线类星体。
We present a pipeline based on a random forest classifier for the identification of high column-density clouds of neutral hydrogen (i.e. the Lyman limit systems, LLSs) in absorption within large spectroscopic surveys of z>3 quasars. We test the performance of this method on mock quasar spectra that reproduce the expected data quality of the Dark Energy Spectroscopic Instrument (DESI) and the WHT Enhanced Area Velocity Explorer (WEAVE) surveys, finding >90% completeness and purity for N(HI)> 10^17.2 cm^-2 LLSs against quasars of g < 23 mag at z~3.5-3.7. After training and applying our method on 10,000 quasar spectra at z~3.5-4.0 from the Sloan Digital Sky Survey (Data Release 16), we identify ~6600 LLSs with N(HI)>10^17.5 cm^-2 between z~3.1-4.0 with a completeness and purity of >90% for the classification of LLSs. Using this sample, we measure a number of LLSs per unit redshift of 2.32 +/- 0.08 at z=[3.3,3.6]. We also present results on the performance of random forest for the measurement of the LLS redshifts and HI column densities, and for the identification of broad absorption line quasars.
