论文标题
基于有限厚的薄盘模型的黑洞自旋测量。MCG-06-30-15的示例研究
Black Hole Spin Measurements Based on a Thin Disc Model with Finite Thickness I. An example study of MCG-06-30-15
论文作者
论文摘要
我们介绍了XMM-Newton和Nustar观察活动的重新分析，以进行精心研究的X射线射击AGN MCG-06-30-15。特别是，我们考虑了一个厚度有限的光盘模型。通过将圆盘反射光谱拟合到数据中，我们在考虑盘的厚度后，获得了一个0.87--0.99（90 \％置信范围）的黑洞自旋。计算MCG-06-30-15计算的，具有从0到$ 30 \％\ dot {m} _ {\ rm edd} $的质量积聚率网格的光谱模型。通过考虑免费的圆盘反射分数参数$ f _ {\ rm refl} $获得此结果，并且与基于剃须刀 - 薄盘模型的先前测量值一致。此外，在我们的模型中假定了各向同性，点状的几何形状，即“灯柱”几何形状。我们发现这种几何形状高估了数据中的$ f _ {\ rm refl} $。因此，$ f _ {\ rm refl} $具有一致的“ lamppost”值的薄盘模型比具有免费的$ f _ {\ rm refl} $参数的薄光盘模型提供的拟合度更低。我们讨论了论文末尾观察到的$ f _ {\ rm refl} $之间差异的可能原因。当在将来的工作中考虑薄盘的厚度时，可能需要对过度简化的灯柱模型进行修改。
We present a re-analysis of the XMM-Newton and NuSTAR observing campaign for the well-studied, X-ray-bright AGN MCG-06-30-15. In particular, we consider a disc model with finite thickness. By fitting the disc reflection spectra in the data, we obtain a black hole spin of 0.87--0.99 (90\% confidence range) after taking the thickness of the disc into consideration. Spectral models with a grid of mass accretion rate from 0 to $30\%\dot{M}_{\rm Edd}$ are calculated for MCG-06-30-15. This result is obtained by considering a free disc reflection fraction parameter $f_{\rm refl}$ and is consistent with previous measurements based on razor-thin disc models. Besides, an isotropic, point-like geometry, i.e. the `lamppost' geometry, is assumed for the corona in our model. We find that such a geometry overestimates $f_{\rm refl}$ in the data. Therefore, thin disc models with consistent `lamppost' values of $f_{\rm refl}$ provide a worse fit than ones with a free $f_{\rm refl}$ parameter. We discuss possible reasons for the discrepancy between the observed and theoretical values of $f_{\rm refl}$ at the end of the paper. Modifications for the over-simplified lamppost model might be needed when the thickness of the thin disc is considered in future work.
