Fermi-LAT-detected blazars fundamental parameters

Aiming to delineate the physical framework of blazars, we present an effective method to estimate four important parameters based on the idea proposed by Becker & Kafatos (1995ApJ...453...83B), 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 Fermi-LAT-detected blazars which had been compiled in Pei+ (2020PASA...37...43P). 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 Becker & Kafatos, 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_disk_/L_Edd_=4.68x10^-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.