HIGH-REDSHIFT NARROW LINE SEYFERT 1 GALAXIES: A CANDIDATE SAMPLE

The study of Narrow line Seyfert 1 galaxies (NLS1s) is now mostly limited to low redshift (z &lt; 0.8). This is because their definition requires the presence of the Hβ emission line, which is red-shifted out of the spectral coverage of major ground-based spectroscopic surveys at z &gt; 0.8. We studied the correlation between the properties of Hβ and Mg II lines of a large sample of SDSS DR14 quasars to find high-z NLS1 candidates. Based on the strong correlation of FWHM(MgII)=(0.880±0.005)×FWHM(Hβ)+(0.438±0.018), we present a sample of high-z NLS1 candidates having FWHM of Mg II &lt; 2000 km s−1. The high-z sample contains 2684 NLS1s with redshift z = 0.8 − 2.5 with a median logarithmic bolometric luminosity of 46.16 ± 0.42 erg s−1, logarithmic black hole mass of 8.01 ± 0.35M⊙, and logarithmic Eddington ratio of 0.02 ± 0.27. The fraction of radio-detected high-z NLS1s is similar to that of the low-z NLS1s and SDSS DR14 quasars at a similar redshift range and their radio luminosity is found to be strongly correlated with their black hole mass. This page contains the catalog of high-z NLS1 candidates.窄线赛弗1星系（Narrow line Seyfert 1 galaxies, NLS1s）的研究目前大多局限于红移z<0.8的低红移样本。这是因为该类天体的定义要求观测到Hβ发射线，而当红移z>0.8时，该谱线会红移至主流地面光谱巡天的光谱覆盖范围之外。我们针对斯隆数字巡天第14次数据发布（SDSS DR14）的大样本类星体，研究了其Hβ与Mg Ⅱ谱线的性质相关性，以搜寻高红移NLS1候选体。基于$ ext{FWHM( ext{Mg} , ext{Ⅱ})}=(0.880pm0.005) imes ext{FWHM( ext{H}eta)}+(0.438pm0.018)$这一显著相关性，我们筛选出Mg Ⅱ半高全宽（Full Width at Half Maximum, FWHM）小于2000 km s⁻¹的高红移NLS1候选体样本。该高红移样本包含2684个红移范围为0.8~2.5的NLS1候选体，其中位数对数总光度为$46.16pm0.42$ erg s⁻¹，对数黑洞质量为$8.01pm0.35M_☉$，对数爱丁顿比率为$0.02pm0.27$。射电探测到的高红移NLS1s占比，与相近红移范围内的低红移NLS1s及SDSS DR14类星体的占比相近；且其射电光度与黑洞质量存在显著相关性。本页面收录了该高红移NLS1候选体星表。