The physical properties of \textit{Fermi} TeV BL Lac objects jets

TL;DR

This study models the spectral energy distributions of 29 Fermi TeV BL Lac objects to explore jet properties, acceleration mechanisms, and energy distributions, revealing correlations and jet power estimates that enhance understanding of blazar jet physics.

Contribution

It provides the first comprehensive modeling of Fermi TeV BL Lac jets using a one-zone leptonic model, uncovering key correlations and jet power relations.

Findings

Negative correlation between magnetic field B and Doppler factor δ.

Energy-dependent acceleration signatures in spectral correlations.

Jets are particle dominated with P_e > P_B and weak dependence on black hole mass.

Abstract

We investigate the physical properties of \textit{Fermi} TeV BL Lac objects jets by modeling the quasi-simultaneous spectral energy distribution of 29 \textit{Fermi} TeV BL Lacs in the frame of a one-zone leptonic synchrotron self-Compton model. Our main results are the following: (i) There is a negative correlation between $B$ and $\delta$ in our sample, which suggests that $B$ and $\delta$ are dependent on each other mainly in Thomson regime. (ii) There are negative correlations between $\nu_{\text{sy}}$ and $r$, the $\nu_{\text{IC}}$ and $r$, which is a signature of the energy-dependence statistical acceleration or the stochastic acceleration. There is a significant correlation between $r$ and $s$, which suggests that the curvature of the electron energy distribution is attributed to the energy-dependence statistical acceleration mechanism. (iii) By assuming one proton per relativistic electron, we estimate the jet power and radiative power. A size relation $P_{\text{e}} \sim P_{\text{p}} > P_{\text{r}} \gtrsim P_{\text{B}}$ is found in our sample. The $P_{\text{e}}>P_{\text{B}}$ suggests that the jets are particle dominated, and the $P_{\text{e}}\sim P_{\text{p}}$ means that the mean energy of relativistic electrons approaches $m_{\text{p}}/m_{\text{e}}$. There are not significant correlations between $P_{\text{jet}}$ and black hole mass in high or low state with a sub-sample of 18 sources, which suggests that the jet power weakly depends on the black hole mass. (iv) There is a correlation between the changes in the flux density at 1 TeV and the changes in the $\gamma_{\text{peak}}$, which suggests the change/evolution of electron energy distribution may be mainly responsible for the flux variation.