SPECTRAL CLASSIFICATION AND REDSHIFT MEASUREMENT FOR THE SDSS-III BARYON OSCILLATION SPECTROSCOPIC SURVEY
SPECTRAL CLASSIFICATION AND REDSHIFT MEASUREMENT FOR THE SDSS-III BARYON OSCILLATION SPECTROSCOPIC SURVEY
复制标题
DOI：
10.1088/0004-6256/144/5/144
复制
发表时间：
2012-07
期刊：
影响因子：
--
通讯作者：
A. Bolton;D. Schlegel;E. Aubourg;Stephen Bailey;V. Bhardwaj;J. Brownstein;S. Burles;Yan-Mei Chen-Yan-Mei-Che
中科院分区：
文献类型：
--
作者：
A. Bolton;D. Schlegel;E. Aubourg;Stephen Bailey;V. Bhardwaj;J. Brownstein;S. Burles;Yan-Mei Chen-Yan-Mei-Che
我们描述了斯隆数字巡天III （SDSS-III）的重子振荡光谱巡天（BOSS）中使用的自动光谱分类、红移测定和参数测量管道，该巡天的第九次数据发布（DR9）包括831,000个中等分辨率光谱。我们回顾了所采用的算法，并描述了BOSS相对于以前的SDSS-I/II版本所实现的管道的变化，包括新的恒星，星系和类星体红移模板集。对于BOSS针对大尺度宇宙学测量的红移0.4≤z≤0.8的大质量星系的颜色选择“CMASS”样本，该管道实现了98.7%的自动分类成功率，并确认了95.4%的唯一CMASS目标为星系（其余大部分为M星）。基于对BOSS星系子集的目视检查，我们发现大约0.2%的自信报告的CMASS样本分类和红移是不正确的，大约0.4%的CMASS光谱是当前算法未分类的对象，这些对象可能是可恢复的。BOSS管道证实，类星体目标中约51.5%具有类星体光谱，平衡主要由恒星和低信噪比光谱组成。从光子噪声传播的统计（与系统相反）红移误差对星系和类星体来说通常都是几十km s - 1，类星体的红移误差有几百km s - 1的显著尾巴。我们使用重复观测来测试这些统计红移误差估计的准确性，发现它们被低估了1.19-1.34倍的星系和2倍的类星体。我们评估了天差质量、信噪比和其他因素对星系红移成功的影响。最后，我们记录了BOSS DR9光谱数据集的已知问题，并描述了正在进行的开发方向。
We describe the automated spectral classification, redshift determination, and parameter measurement pipeline in use for the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey III (SDSS-III) as of the survey's ninth data release (DR9), encompassing 831,000 moderate-resolution optical spectra. We give a review of the algorithms employed, and describe the changes to the pipeline that have been implemented for BOSS relative to previous SDSS-I/II versions, including new sets of stellar, galaxy, and quasar redshift templates. For the color-selected “CMASS” sample of massive galaxies at redshift 0.4 ≲ z ≲ 0.8 targeted by BOSS for the purposes of large-scale cosmological measurements, the pipeline achieves an automated classification success rate of 98.7% and confirms 95.4% of unique CMASS targets as galaxies (with the balance being mostly M stars). Based on visual inspections of a subset of BOSS galaxies, we find that approximately 0.2% of confidently reported CMASS sample classifications and redshifts are incorrect, and about 0.4% of all CMASS spectra are objects unclassified by the current algorithm which are potentially recoverable. The BOSS pipeline confirms that ∼51.5% of the quasar targets have quasar spectra, with the balance mainly consisting of stars and low signal-to-noise spectra. Statistical (as opposed to systematic) redshift errors propagated from photon noise are typically a few tens of km s−1 for both galaxies and quasars, with a significant tail to a few hundreds of km s−1 for quasars. We test the accuracy of these statistical redshift error estimates using repeat observations, finding them underestimated by a factor of 1.19–1.34 for galaxies and by a factor of two for quasars. We assess the impact of sky-subtraction quality, signal-to-noise ratio, and other factors on galaxy redshift success. Finally, we document known issues with the BOSS DR9 spectroscopic data set and describe directions of ongoing development.