我们选择了292个SDSS窄发射线星系的样本，这些星系在相对孤立的情况下形成和演化，以研究活动星系核现象的性质和起源。我们样本中的星系具有S/N>3的线通量，并使用标准诊断图将其分为恒星形成星系团（SFG; 36.0%），过渡型天体（TO; 28.4%）和窄线活动星系核（NLAGN; 35.6%）。在发现了核球质量与NLAGN现象之间的强相关性之后，我们应用与宽线活动星系核相同的关系来估计它们的黑洞（BH）质量。NLAGN中的BH在质量上比BLAGN中发现的BH低2到3个数量级，但与窄线塞弗特~1中观察到的BH相当，尽管我们的物体都不能被归类为这样。为了确定NLAGN的金属丰度[O/H]，我们使用与SFG相似的关系校准了标准诊断图[OIII]/Hb vs. [NII]/Ha，其重现了Bennert等人[3]开发的CLOUDY模拟获得的值。对于一些个别的对象，我们比较了我们的线比与其他云的相似不同的作者。这表明我们在[O/H]上获得了0.2 dex的典型不确定度，在Seyfert~2（S2）中增加到0.3-0.5。这种校准表明NLAGN的金属丰度是太阳下的，在1和0.3 $Z_\odot$之间变化。我们发现两个统计上显著的正相关：[O/H]与BH质量和[O/H]与5100 nm处的光度，$λL(5100$与$)$。[O/H]与吸积速率L_bol/L_Edd之间没有相关性。然而，与BLAGN的比较表明，NLAGN将金属丰度-吸积率关系[24]扩展到低金属丰度区域。虽然NLS 1与NLAGN具有相似的BH质量，但它们显示出更高的吸积速率，这与它们更高的金属丰度相一致。
英文摘要：
We have selected a sample of 292 SDSS Narrow-Emission-Line galaxies known to have formed and evolved in relative isolation to study the nature and origin of the AGN phenomenon. The galaxies in our sample have line fluxes with S/N>3 and were separated using a standard diagnostic diagram into Star Forming Galaxies (SFGs; 36.0%), Transition type Objects (TOs; 28.4%) and Narrow-Line AGNs (NLAGNs; 35.6%). Having found a strong correlation between the bulge mass and the NLAGN phenomenon, we have applied the same relation as for the Broad-Line AGNs to estimate their black hole (BH) masses. The BH in the NLAGNs are 2 to 3 orders lower in mass than the BHs found in BLAGNs, but are comparable to those observed in Narrow-Line Seyfert~1, although none of our objects can be classified as such. To determine the metallicities, [O/H], of the NLAGNs we calibrated the standard diagnostic diagram [OIII]/Hb vs. [NII]/Ha using similar relation as for the SFGs, which reproduce the values obtained with CLOUDY simulations developed for Bennert et al. [3]. For some individual objects we compared our line ratios with other CLOUDY similations by different authors. This suggests we achieve a typical uncertainty of 0.2 dex on [O/H], increasing to 0.3-0.5 in the Seyfert~2 (S2). This calibration suggests the metallicities of the NLAGNs are subsolar, varying between 1 and 0.3 $Z_\odot$. We find two statistically significant positive correlations: for [O/H] with the BH mass and for [O/H] with the luminosity at 5100Å, $λL(5100$Å$)$. No correlation is found between [O/H] and the accretion rate, L_bol/L_Edd. However, comparisons with the BLAGNs suggest the NLAGNs extend the metallicity-accretion rate relationship [24] to the low metallicity regime. Although the NLS1 have similar BH masses as the NLAGNs they show higher accretion rates, which is consistent with their higher metallicities.
Low-Redshift Ly-alpha Selected Galaxies from GALEX Spectroscopy: A Comparison with Both UV-Continuum Selected Galaxies and High-Redshift Ly-alpha Emitters
