We fit the (quasi-)simultaneous multi-waveband spectral energy distributions (SEDs) for a sample of low-synchrotron-peaked (LSP) blazars with a one-zone leptonic model. The seed photons that predominantly come from broad line region (BLR) and infrared (IR) molecular torus are considered respectively in external Compton process. We find that the modeling with IR seed photons is systematically better than that with BLR photons based on a χ 2 test, which suggest that γ-ray emitting region most possibly stay outside the BLR. The minimum electron Lorentz factor, γ min , is constrained from the modeling for these LSP blazars with good soft X-ray data (ranges from 5 to 160 with a median value of 55), which plays a key role in jet power estimation. Assuming one-to-one ratio of proton and electron, we find that the jet power for LSP blazars is systematically higher than that of FR II radio galaxies at given 151 MHz radio luminosity, L 151MHz , even though FR IIs are regarded as same as LSP blazars in unification scheme except the jet viewing angle. The possible reason is that there are some e ± pairs in the jet of these blazars. If this is the case, we find the number density of e ± pairs should be several times higher than that of e − − p pairs by assuming the jet power is the same for LSP blazars and FR IIs at given L 151MHz .

S5 0716+714 is a typical BL Lacertae object. In this paper we present the analysis and results of long-term simultaneous observations in the radio, near-infrared, optical, X-ray, and γ -ray bands, together with our own photometric observations for this source. The light curves show that the variability amplitudes in γ -ray and optical bands are larger than those in the hard X-ray and radio bands and that the spectral energy distribution (SED) peaks move to shorter wavelengths when the source becomes brighter, which is similar to other blazars, i.e., more variable at wavelengths shorter than the SED peak frequencies. Analysis shows that the characteristic variability timescales in the 14.5 GHz, the optical, the X-ray, and the γ -ray bands are comparable to each other. The variations of the hard X-ray and 14.5 GHz emissions are correlated with zero lag, and so are the V band and γ -ray variations, which are consistent with the leptonic models. Coincidences of γ -ray and optical flares with a dramatic change of the optical polarization are detected. Hadronic models do not have the same natural explanation for these observations as the leptonic models. A strong optical flare correlating a γ -ray flare whose peak flux is lower than the average flux is detected. The leptonic model can explain this variability phenomenon through simultaneous SED modeling. Different leptonic models are distinguished by average SED modeling. The synchrotron plus synchrotron selfCompton (SSC) model is ruled out because of the extreme input parameters. Scattering of external seed photons, such as the hot-dust or broad-line region emission, and the SSC process are probably both needed to explain the γ -ray emission of S5 0716+714.

Plasmonic nanostructures can significantly improve the performance of photoconductive devices (PCDs). In the mean time, they introduce intricate structures and complex scattering, which lead new challenges to simulations.In this work, a multiphysics framework based on discontinuous Galerkin (DG) methods is proposed to model the nonlinearly-coupled multiphysics processes in plasmonic PCDs. Without optical pumping, the nonequilibrium steadystate of the device, described by a coupled Poisson/drift-diffusion (DD) system, is solved with the Gummel iteration method. With pumping, the wave scattering, carrier dynamics and their nonlinear interactions are modeled by an explicit time domain solver solving the coupled system of Maxwell/time-dependent DD equations. The DD equations and Poisson equation are discretized with the local DG method and Maxwell equations are discretized with the nodal DG method. The DG-based multiphysics framework provides favorable discretization flexibilities for modeling the multiscale features in plasmonic PCDs. The proposed framework is demonstrated with simulations of a conventional PCD and a plasmonic PCD.

PKS 1424+240 is a distant very high energy gamma-ray BL Lac object with redshift z = 0.601. It was found that pure synchrotron self-Compton (SSC) process normally need extreme input parameters (e.g., very low magnetic field intensity and extraordinarily large Doppler factor) to explain its multi-wavelength spectral energy distributions (SEDs). To avoid the extreme model parameters, different models have been proposed (e.g., two-zone SSC model or lepto-hadronic model). In this work, we employ the traditional one-zone leptonic model after including a weak external Compton component to re-explore the simultaneous multi-wavelength SEDs of PKS 1424+240 in both high (2009) and low (2013) states. We find that the input parameters of magnetic field and Doppler factor are roughly consistent with those of other BL Lacs if a weak external photon field from either broad line region (BLR) or the dust torus. However, the required energy density of seed photons from BLR or torus is about 3 orders of magnitude less than that constrained in luminous quasars (e.g., flat-spectrum radio quasars, FSRQs). This result suggests that the BLR/torus in BL Lacs is much weaker than that of luminous FSRQs (but not fully disappear), and the inverse-Compton of external photons from BLR/torus may still play a role even in high synchrotron peaked blazars.

In recent years, extensive attention has been focused on a new topological phase induced by nonmagnetic disorder, known as the topological Anderson insulator (TAI). In this work, we study the disorder strength dependence of the edge states in TAI phase in disordered HgTe/CdTe quantum wells. It is shown clearly that the disorder-induced edge states appear above a critical disorder strength after a gap-closing phase transition. These edge states are then found to decline with an increase of disorder strength in a stepwise pattern due to the finite-width effect, where the opposite edges couple to each other through the localized bulk states. This is in sharp contrast with the localization of the edge states themselves by time-reversal symmetry breaking. The size-independent phase boundaries are further obtained through scaling analysis, where a metallic phase is found separating two topologically distinct phases, which is due to the Fermi energy and mass renormalization. A. The complete dependence of the energy spectrum on disorder strength in disordered HgTe/CdTe quantum wells (QWs) 13 Appendix B. Comparison of the energy spectrum in disordered HgTe/CdTe QWs between periodic and open boundary conditions in the y-direction 14 Appendix C. Spin-momentum locking of the edge states in disordered HgTe/CdTe QWs in the topological Anderson insulator phase 14 References 15