利用昴星团望远镜“Onohi'ula”PFS-SSP发现4个红移z=2.54至6.06的窄线1型类星体
Discovery of four Narrow-line Type-1 Quasars at z = 2.54 -- 6.06 with Subaru 'Onohi'ula PFS-SSP
AI总结：
本研究利用昴星团望远镜PFS-SSP在z=2.54至6.06处发现4个窄线1型类星体，通过Lyα线筛选，测得其参数与低红移NLS1星系相符，1个为mini-BAL类星体，证实其为NLS1的亮版本
AI中文摘要：
我们报告利用昴星团望远镜“Onohi'ula”主焦点光谱仪 Subaru 战略计划（PFS-SSP）发现4个窄线1型类星体（NLQ1s）的成果。为了将对这类天体的全面认知拓展至遥远宇宙，我们利用莱曼α（Lyα）线轮廓，搜寻静止紫外光谱形态与本地窄线赛弗特1星系（NLS1星系）相似的宽线活动星系核（类星体），并在红移z=2.54至6.06范围内确认了4个NLQ1s（含1个候选体）。获取的光谱显示出显著的Lyα发射线，且连续谱水平极低。测得Lyα的半高全宽（FWHM）范围为1410 km/s至1510 km/s，平均值约为1430 km/s。尽管我们仅利用线宽信息筛选NLQ1s，但所得Lyα的等效宽度（EW）高于类星体的典型值，静止坐标系下平均值约为190 Å。其中2个类星体拥有异常高的Lyα光度，占总光度的3%至4%。对3个可获取碳IV（C IV）线的天体，我们测量了其黑洞质量与爱丁顿比率，测得黑洞质量范围为10^6.9至10^7.7倍太阳质量，且爱丁顿比率较高（>0.1），与低红移宇宙中报道的NLS1星系结果一致。在1个天体中检测到氮V（N V）和C IV宽吸收线，该类星体可归类为迷你宽吸收线（mini-BAL）类星体，进一步支持该NLQ1确实是NLS1星系的亮版本这一观点。
英文摘要：
We report the discovery of four narrow-line type-1 quasars (NLQ1s) from the Subaru 'Onohi'ula Prime Focus Spectrograph Subaru Strategic Program (PFS-SSP). To extend a comprehensive understanding of this population to the distant universe, we searched for broad-line AGNs (quasars) whose rest-UV spectral shapes resemble those of local NLS1 galaxies, utilizing the Ly$α$ line profile. We identified four NLQ1s, including one candidate, at $z=2.54$ -- $6.06$. The obtained spectra show a prominent Ly$α$ emission line with a very low continuum level. The measured full width at half maximum (FWHM) of Ly$α$ ranges from $1410 \ \mathrm{km\,s^{-1}}$ to $1510 \ \mathrm{km\,s^{-1}}$ with a mean of $\sim 1430 \,\mathrm{km\,s^{-1}}$. Although we used only line width information for the NLQ1 selection, the resulting equivalent widths (EW) of Ly$α$ are higher (the mean $\sim 190$\,Å\ in the rest frame) than the typical values of quasars. Two quasars have exceptionally large Ly$α$ luminosity, accounting for $\sim 3$ -- $4$\% of the bolometric luminosity. We measured black hole masses and Eddington ratios for three objects whose C\,\textsc{iv} line is available. The resulting black hole masses are $\sim 10^{6.9}$ -- $10^{7.7}\, M_{\odot}$ with high Eddington ratios ($> 0.1$), consistent with those of NLS1 galaxies reported in the low-$z$ universe. N\,\textsc{v} and C\,\textsc{iv} broad absorption lines are detected in one object. This quasar can be classified as a mini-BAL quasar, which further supports the idea that this NLQ1 is indeed a luminous version of an NLS1 galaxy.
