http://arxiv.org/abs/2112.00530
Aiming to delineate the physical framework of blazars, we present an effective method to estimate four important parameters based on the idea proposed by \citet{BK95}, including the upper limit of central black hole mass $M$, the Doppler factor $\delta$, the distance along the axis to the site of the $\gamma$-ray production $d$ (which then can be transformed into the location of $\gamma$-ray-emitting region $R_{\gamma}$) and the propagation angle with respect to the axis of the accretion disk $\Phi$. To do so, we adopt an identical sample with 809 {\it Fermi}-LAT-detected blazars which had been compiled in \citet{Pei20PASA}. These four derived parameters stepping onto the stage may shed new light on our knowledge regarding $\gamma$-ray blazars. With regard to the paper of \citet{BK95}, we obtain several new perspectives, mainly in: (1) putting forward an updated demarcation between BL Lacs and FSRQs based on the relation between broad-line region luminosity and disk luminosity both measured in Eddington units, i.e., $L_{\rm disk}/L_{\rm Edd}=4.68\times10^{-3}$, indicating that there are some differences between BL Lacs and FSRQs on the accretion power in the disk; (2) proposing that there is a so-called `appareling zone’, a potential transition field between BL Lacs and FSRQs where the changing-look blazars perhaps reside; (3) the location of $\gamma$-ray emission region is principally constrained outside the broad-line region, and for some BL Lacs are also away from the dusty molecular torus, which means the importance of emission components in the jet.
Z. Pei, J. Fan, J. Yang, et. al.
Thu, 2 Dec 21
40/61
Comments: 24 pages, 9 figures, Accepted to ApJ