A5011268144- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Solar and Space Plasma Dynamics
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Radio Astronomy Observations and Technology
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Star Formation Studies
- Particle Detector Development and Performance
- Cosmology and Gravitation Theories
- International Science and Diplomacy
- Particle physics theoretical and experimental studies
Yuxi Normal University
2016-2024
Yunnan University
2016-2024
Abstract The classification of gamma-ray bursts (GRBs) has long been an unresolved problem. Early long- and short-burst based on duration is not convincing owing to the significant overlap in plot, which leads different views results. We propose a new method convolutional neural networks adopt sample including 3774 GRBs observed by Fermi-GBM address T 90 By using count maps that incorporate both temporal spectral features as inputs, we successfully classify 593 overlapping events into two...
Abstract The broadband emission of numerous pulsar wind nebula (PWNe) in our Galaxy can be well described by synchrotron radiation and inverse Compton scattering from relativistic particles, specifically electrons positrons. However, the particle transport mechanism is still under debate. We use here a time-dependent model to investigate process young PWN, while cooling processes are also analyzed. Following applications six PWNe, results show that (1) dominated adiabatic loss low-energy...
Multi-band emission from radio to ultra-high energy gamma-rays in the Crab Nebula has been detected. To explain observed results, non-thermal photon production \textbf{in} is carefully studied a spatially dependent lepto-hadronic model. In our model, dynamical evolution of PWN simulated spherically symmetric system. Both electrons and protons are accelerated at termination shock. The relevant particle propagation equations as well evolving equation simultaneously solved. For Nebula, results...
Abstract Pulsar wind nebula HESS J1849-000 is one of the sources that may emit PeV γ -ray photons based on recent measurement by Tibet Air Shower Array and Large High Altitude Observatory. We use a time-dependent model to investigate nonthermal radiative properties J1849-000. Observed multiband data are produced well relativistic leptons through synchrotron radiation inverse Compton processes, particle transport cooling processes analyzed. Our results show adiabatic loss dominates over...
Abstract Magnetars are neutron stars with extremely strong magnetic fields, frequently powering high-energy activity in X-rays. Pulsed radio emission following some X-ray outbursts has been detected, albeit its physical origin is unclear. It long speculated that the of magnetars’ signals different from those canonical pulsars, although convincing evidence still lacking. Five months after magnetar SGR 1935+2154's outburst and associated fast burst 20200428, a pulsar phase was discovered. Here...
ABSTRACT A self-consistent and spatially dependent model is presented to investigate the multiband emission of pulsar wind nebulae (PWNe). In this model, a spherically symmetric system assumed dynamical evolution PWN included. The processes convection, diffusion, adiabatic loss, radiative photon–photon pair production are taken into account in electron’s equation, synchrotron radiation, inverse Compton scattering, self-absorption, included for photon’s equation. Both coupled equations...
Abstract We propose a jet helical motion model to explain the γ -ray quasiperiodic oscillation of PG 1553+113. In this model, we hypothesize that relativistic with constant angular velocity rotates around axis, causing Doppler factor vary over time, leading periodic changes in flux. addition, consider parameters emission field slightly during observation period and can be obtained by directly fitting their multiwavelength spectra. Then, use resulting information reproduce light curve. Our...
Abstract A turbulent diffusion model is presented to account for the energy and spatial of particles within pulsar wind nebulae (PWNe), with assumption that injected from into nebula split between turbulence waves electrons/positrons. In model, mutual interactions are taken account, representing damping effect stochastic acceleration particles, respectively. The evolutions described coupled kinetic equations, in which Kolmogorov- Kraichnan-type are, respectively, considered. applied Crab...
ABSTRACT We examine the fundamental plane of 91 blazars which include flat-spectrum radio quasars and BL Lacertae objects with known X-ray luminosity (LR), (LX), black hole mass measurements (M) to reflect relationship between jet accretion for blazars. The are logLR = ${0.273}_{+0.059}^{-0.059}\log L_X$ + ${0.695}_{+0.191}^{-0.191}\log M$ ${25.457}_{+2.728}^{-2.728}$ ${0.190}_{+0.049}^{-0.049}\log ${0.475}_{+0.157}^{-0.157}\log ${28.568}_{+2.245}^{-2.245}$ after considering effect beam...
Aims. Nonthermal radiation properties of pulsar wind nebulae (PWNe) are studied in the frame a time-dependent model with particle advection and diffusion. Methods. The dynamical radiative evolution PWN was self-consistently solved model. lepton (electrons positrons) equation is described by injection, advection, diffusion, adiabatic loss, loss. emission from mainly produced relativistic leptons through synchrotron inverse Compton process. Results. effect transport including diffusion...
Observations of two pulsar wind nebulae (PWNe) 3C 58 and G21.5−0.9 indicate that they have mostly symmetric spherical morphologies, emit photons from radio to γ-rays the radial variations photon indices in X-ray band. The spatially radiative properties are modelled frame a dependent model. Combining with dynamical evolution each PWN, time spectral energy distributions (SEDs) calculated. Our modelling results show observed multiband SEDs band these PWNe can be reproduced well. From results,...
ABSTRACT 3C 58 is a pulsar wind nebula (PWN) that shows an interesting energy-dependent extent and spatial variations of the photon index surface brightness in X-ray band. These observations provide useful information with which to study spatially dependent radiative cooling electrons transport mechanisms within nebula. In this paper, resolved spectra PWN are investigated framework particle model. The nebula, including spectral energy distribution, spectrum, measurements extent, can be...
Abstract We have systemically studied the properties of 1ES 1959+650, specifically its multiband variability and emission mechanisms. carefully analyze by four different kinds trusted approaches. In contrast with previous research thanks to our more detailed data, we find that an unprecedented significant quasi-periodic component timescale <?CDATA $P={266.2}_{-7.2}^{+7.5}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>P</mml:mi> <mml:mo>=</mml:mo>...
Using the standard one-zone synchrotron self-Compton (SSC) model and Markov chain Monte Carlo (MCMC) technique, we systematically analyze quasi-simultaneous multi-wavelength (MWL) spectral energy distributions (SEDs) of Mrk 421 501 during states relatively low activity. With this in place, a semi-analytical method is developed to examine uncertainty jet power estimation caused by degeneracy radiative models. The method, combination with MCMC allows us explore properties over wide range...
ABSTRACT Pulsar wind nebula (PWN) HESS J1825-137 is one of the largest and brightest gamma-ray sources in Milky Way. It was found that morphology strongly depends on energy photon spectrum varies obviously with distance from pulsar &gt;0.1 TeV band. In frame a spatially-dependent particle transport model, we investigate observed features by using Markov chain Monte Carlo method. Our results are as follows: (i) can be reasonably explained competition between (advection diffusion) cooling...
We present a one-zone homogeneous self-consistent model for the multiwavelength emission features of PKS 1424+240 that allows effects automatic photon quenching to be studied. In model, steady γ-ray injection rate in source is assumed and non-linear time-dependent kinematic equations describing evolution both electrons photons are then acquired; these self-consistently involve photon–photon interaction, synchrotron radiation electron/positron pairs, inverse Compton scattering...
Context . Vela X is a middle-aged pulsar wind nebula (PWN) that has been detected in radio, X-ray, and γ -ray bands. The observations indicate photon index flux density of the inner regions have obvious changes as radial distance increases X-ray band, surface brightness discovered to decrease with increase band. Aims multi-band emission high energy spatially radiative properties are investigated framework dependent particle transport model. Methods Electron distribution inside PWN was...
Observations of plerionic supernova remnant (SNR) G21.5-0.9 indicate an extended X-ray halo surrounding the bright central pulsar wind nebula (PWN), and that photon index surface brightness SNR have been discovered to change with increase radial distance in band. To explain observational features this source, a two-zone spatially dependent model slow diffusion PWN fast region is proposed paper. In model, evolution electron inside entire described particle transport equation under assumption...
Abstract We present periodicity search analyses on the long-term γ -ray light curve of BL Lacertae object 4FGL J2139.4−4235 observed by Fermi Large Area Telescope, over a period more than 15 yr, from 2008 August 4 to 2023 December 10. To determine quasiperiodic oscillation (QPO) behavior in 0.3–300 GeV energy range, we used four methods, namely Lomb–Scargle periodogram, weighted wavelet z-transform, phase dispersion minimization, and autoregressive integrated moving average model. A Monte...
Abstract We present the statistical results of GeV spectral breaks bright gamma-ray flat-spectrum radio quasars (FSRQs) in energy range 0.1–10 based on New Pass 8 data Large Area Telescope board Fermi Gamma-Ray Space Telescope. have fitted 15 yr average spectra 755 FSRQs by using both broken power law (BPL) and logarithmic parabola (LP) models, obtained 87 with their integrated photon fluxes greater than 2.16 × 10 −8 cm −2 s −1 . From our results, FSRQ population shows similar preferences...
Abstract Turbulent transport characteristics of the particles within two Crab-like pulsar wind nebulae (PWNe), 3C58 and G54.1+0.3, are investigated in framework a time-dependent turbulent diffusion model. The model takes gyroresonant interactions between waves into account, which enables us to self-consistently determine energy spatial coefficients nebula via distributions waves. Our application multiband emission from G54.1+0.3 reveals following. (1) seem follow quasi-linear Kolmogorov-type...
We investigate the spatial dependence of high energy electrons and their radiations in pulsar wind nebulae (PWNe). By assuming a time-dependent broken power-law injection convection velocity, magnetic field strength diffusion coefficient on radial distance an expanding system, we numerically solve Fokker-Planck transport equation including convection, diffusion, adiabatic loss radiative spherical coordinates, effects field, PWN age, maximum electrons, electron spectra non-thermal photon...
ABSTRACT The multiband photon emission and spectral evolution of G54.1+0.3 are investigated in the framework leptonic leptonic–hadronic models. We model energy distribution (SED) pulsar wind nebula (PWN) find that both models can well reproduce observations with appropriate parameters. Combining dynamical PWN, we investigate time SED radiative luminosity X-ray TeV γ-ray bands G54.1+0.3. results indicate synchrotron spectrum band PWN calculated these two have obvious differences as age...
Abstract We present a one-zone homogeneous lepton-hadronic model and obtain steady-state spectra by solving the time-dependent equations to study plausible origin of hard TeV in PKS 2155–304. In this model, we assume steady electron proton injection rate source solve non-linear kinematic that self-consistently consist proton-photon interaction, synchrotron radiation electron/positron pairs proton, inverse Compton scattering, self-absorption. employ reproduce multi-wavelength spectrum...