论文标题
无线电排放对无线电定价的爱丁顿比率的依赖性
Dependence of the Radio Emission on the Eddington Ratio of Radio-Quiet Quasars
论文作者
论文摘要
大约10％的类星体是“无线电大声”，在大型喷气机中产生大量的无线电发射。从其余90％的类星体中看到的低级无线电发射的起源尚不清楚。观察具有非常长的基线阵列的八个放射定价类星体的样本，我们发现它们的无线电特性在很大程度上取决于其爱丁顿的比率（r_edd = l_agn/l_edd）。在较低的Eddington比率（R_EDD <0.3）下，AGN的总无线电发射主要源于极度紧凑的区域，可能与增生磁盘一样小。在较高的爱丁顿比率（R_EDD> 0.3）下，该紧凑型区域的相对贡献显着降低，尽管总的无线电功率保持差异大致相同，但该发射现在起源于大于100 pc的区域。带有R_EDD的放射发射等离子体区域的物理起源的变化是出乎意料的，因为Radio-Loud类星体的特性与Eddington Batio没有依赖性。我们的结果表明，在较低的Eddington比率下，磁化的血浆很可能受积聚磁盘电晕的限制，并且只有在较高的Eddington比率下才能逃脱到更大的尺度。恒星质量的黑洞显示出其无线电性能对吸积率的相似依赖性，从而支持将积聚到整个质量范围的黑洞上的范式。
Roughly 10% of quasars are "radio-loud", producing copious radio emission in large jets. The origin of the low-level radio emission seen from the remaining 90% of quasars is unclear. Observing a sample of eight radio-quiet quasars with the Very Long Baseline Array, we discovered that their radio properties depend strongly on their Eddington ratio (r_Edd=L_AGN/L_Edd). At lower Eddington ratios (r_Edd < 0.3), the total radio emission of the AGN predominately originates from an extremely compact region, possibly as small as the accretion disk. At higher Eddington ratios (r_Edd > 0.3), the relative contribution of this compact region decreases significantly, and though the total radio power remains about the same, the emission now originates from regions >100 pc large. The change in the physical origin of the radio-emitting plasma region with r_Edd is unexpected, as the properties of radio-loud quasars show no dependence with Eddington ratio. Our results suggest that at lower Eddington ratios the magnetised plasma is likely confined by the accretion disk corona, and only at higher Eddington ratios escapes to larger scales. Stellar-mass black holes show a similar dependence of their radio properties on the accretion rate, supporting the paradigm which unifies the accretion onto black holes across the mass range.
