The study of narrow-line Seyfert 1 galaxies (NLS1s) is now mostly limited to low redshift (z < 0.8) because their definition requires the presence of the Hβ emission line, which is redshifted out of the spectral coverage of major ground-based spectroscopic surveys at z > 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(Mg II) = (0.880 0.005) FWHM(Hβ) + (0.438 0.018), we present a sample of high-z NLS1 candidates having FWHM of Mg ii < 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 0.35 M _⊙, 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.

窄线的赛弗特1个星系（NLS1s）的研究现在大多局限于低红移（Ž <0.8），因为它们的定义需要H的存在β发射线，这是红移的基于地面主要的光谱范围的出z > 0.8的光谱调查。我们研究了H的性质之间的相关性β和Mg II类星体找到高线SDSS DR14的大样本的Ž NLS1候选。基于FWHM（镁的强相关性II）=（0.880 0.005）FWHM（H β）+（0.438 0.018）中，我们提出高的样品ž具有的Mg的FWHM NLS1候选II <2000年公里S^-1。所述高ž样品含有2684个NLS1s与红移Ž = 0.8-2.5与46.16 0.42尔格秒的平均对数热光度^-1，8.01 0.35对数黑洞质量中号 _⊙，和0.02 0.27对数的Eddington比率。在相似的红移范围内，无线电探测到的高z NLS1的分数与低z NLS1和SDSS DR14类星体的分数相似，并且发现其无线电发光度与其黑洞质量密切相关。