THE RADIATIVE EFFICIENCY OF ACCRETION FLOWS IN INDIVIDUAL ACTIVE GALACTIC NUCLEI
THE RADIATIVE EFFICIENCY OF ACCRETION FLOWS IN INDIVIDUAL ACTIVE GALACTIC NUCLEI
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DOI：
10.1088/0004-637x/728/2/98
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发表时间：
2011-02-20
影响因子：
4.9
通讯作者：
Laor, Ari
中科院分区：
文献类型：
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作者：
Davis, Shane W.;Laor, Ari
活动星系核（AGN）的辐射效率通常是根据吸积的总质量和宇宙中每单位体积AGN发出的总光随时间的积分来估算的（Soltan论点）。在单个活动星系核中，薄吸积盘模型谱拟合可以用来推导绝对吸积率M。如果黑洞的质量M是已知的。辐射效率。然后由测热光度L-bol与（M）除以dotc（2）的比值设定。我们用这种方法来确定。在80个具有确定的L-bol的Palomar-Green类星体的样本中，其中（M）由薄吸积盘模型拟合光学光度密度，M的确定基于球核恒星速度色散（13个天体）或宽线区。我们推导出平均log eta = -1.05 +/- 0.52，与基于Soltan自变量的估计值一致。我们发现eta与M的强相关性，从M = 10（7）M-圆点和L/L-Edd类似于1的eta类似于0.03上升到M = 10（9）M-圆点和L/L-Edd类似于0.3的eta类似于0.4。这种趋势与我们的样品中L-opt/L-bol的总体均匀性有关，特别是L-opt/L-bol没有随着M增加（和L/L-Edd降低）而预期增加，这是固定eta下热盘发射的一般性质。M测定的显著不确定度不足以消除相关性。η随M的增加可能意味着黑洞自旋随M的增加，这是基于其他间接论证提出的。
The radiative efficiency of active galactic nucleus (AGN) is commonly estimated based on the total mass accreted and the total AGN light emitted per unit volume in the universe integrated over time (the Soltan argument). In individual AGNs, thin accretion disk model spectral fits can be used to deduce the absolute accretion rate M., if the black hole mass M is known. The radiative efficiency. is then set by the ratio of the bolometric luminosity L-bol to (M) over dotc(2). We apply this method to determine. in a sample of 80 Palomar-Green quasars with well-determined L-bol, where (M) over dot is set by thin accretion disk model fits to the optical luminosity density, and the M determination based on the bulge stellar velocity dispersion (13 objects) or the broad line region. We derive a mean log eta = -1.05 +/- 0.52 consistent with the Soltan-argument-based estimates. We find a strong correlation of eta with M, rising from eta similar to 0.03 at M = 10(7) M-circle dot and L/L-Edd similar to 1 to eta similar to 0.4 at M = 10(9) M-circle dot and L/L-Edd similar to 0.3. This trend is related to the overall uniformity of L-opt/L-bol in our sample, particularly the lack of the expected increase in L-opt/L-bol with increasing M (and decreasing L/L-Edd), which is a generic property of thermal disk emission at fixed eta. The significant uncertainty in the M determination is not large enough to remove the correlation. The rising eta with M may imply a rise in the black hole spin with M, as proposed based on other indirect arguments.