A5029576541- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Atomic and Subatomic Physics Research
- Underwater Acoustics Research
- Advanced Differential Geometry Research
- Nuclear Physics and Applications
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Particle Detector Development and Performance
- Cosmology and Gravitation Theories
Jilin University
2020-2024
Purple Mountain Observatory
2018-2019
Nanjing University
2016-2019
Ministry of Education of the People's Republic of China
2016
Centrum Badań Kosmicznych
2016
National Institute for Astrophysics
2016
Institute of Theoretical Physics
2010
Chinese Academy of Sciences
2010
University of Science and Technology of China
2010
ABSTRACT In previous studies, the time evolution information is missed in deducing time-integrated polarizations of gamma-ray burst prompt emission. Here, it considered and investigated through summation time-resolved ones. The statistical properties distribution polarization degree (Π) can be read from q–Π curve, where q ≡ θV/θj. θV θj are observational jet half-opening angles, respectively. Hence, only curves studied. addition to a toroidal magnetic field radiation region, an aligned also...
Polarization spectra had been predicted within the photosphere model. For purpose of seeking more clues to distinguish between models, both time-resolved and time-integrated polarization from optical band MeV gamma-rays magnetic reconnection model are studied here. There two newly found differences models. First, degree (PD) would in general increase with frequency for on-axis observations, while it is not monotonous Second, variations angles (PAs) random, PA varies randomly Therefore,...
Abstract Polarization spectra were predicted within the photosphere model. To seek more clues to distinguish between models, both time-resolved and time-integrated polarization from optical band MeV gamma-rays of magnetic reconnection model are studied here. There two newly found differences models. First, degree would in general increase with frequency for on-axis observations, while it is not monotonous Second, variations angles (PAs) random, PA varies randomly Therefore, future...
Abstract The rotations of the polarization angle (PA) with time (energy) can lead to depolarization time-integrated (energy-integrated) polarization. However, we do not know how and when it will rotate. Here, consider a magnetic reconnection model investigate polarizations, especially PA gamma-ray burst (GRB) prompt emission. For large-scale ordered aligned field configuration, find that within T 50 PAs rotate for slight off-axis observations. Our studies show are due changes in observed...
Aims. With the accumulation of polarization data in gamma-ray burst (GRB) prompt phase, models can be tested. Methods. We predicted time-integrated polarizations 37 GRBs with observation. used their observed spectral parameters to do this. In model, emission mechanism is synchrotron radiation, and magnetic field configuration region was assumed large-scale ordered. Therefore, degrees (PDs) are upper limits. Results. For most detected by Gamma-ray Burst Polarimeter (GAP), POLAR, AstroSat, PD...
The possibility of reconstructing a spherically symmetric inhomogeneous Lemaitre-Tolman-Bondi (LTB) model with $\Lambda$CDM observations has drawn lot attention. Recently, LTB having the same luminosity-distance and light-cone mass density as was reconstructed. We calculate cosmic age at our position in this model, get $t_{LTB}<11.7$Gyr 2$\sigma$ confidence level from Seven-Year WMAP observations. This result is inconsistent some Milky Way
Abstract Besides light curves and spectra, polarization provides a different powerful tool of studying the gamma-ray burst (GRB) prompt phase. Compared with time-integrated energy-integrated polarization, time-resolved energy-resolved can deliver more physical information about emitting region. Here we investigate GRB emission using synchrotron models. We find that equal arrival time surface effect is very important in shaping degree (PD) when conditions region change violently radius....
The central engine and jet composition of gamma-ray bursts (GRBs) remain mysterious. Here we suggest that observations on polarization evolution early optical afterglows may shed light these questions. We first study the dynamics a reverse shock forward are generated during interaction relativistic its ambient medium. is likely magnetized with globally large-scale magnetic field from engine. existence requires magnetization degree should not be high ($\sigma\leq 1$), so mainly composed...
Abstract Gamma-ray bursts have been widely argued to originate from binary compact object mergers or core collapse of massive stars. Jets these systems may two components: an inner, narrow sub-jet and outer, wider sub-jet. Such a jet subsequently interacts with its ambient gas, leading reverse shock (RS) forward shock. The magnetic field in the is very likely be mixed by ordered component random during afterglow phase. In this paper, we calculate light curves polarization evolution optical...
Abstract A large-scale ordered magnetic field plays a very important role in the formation and acceleration of gamma-ray burst (GRB) jet. During GRB prompt phase, some dissipation processes may occur disturb field, making become random to extent. Therefore, mixed consisting an component is plausible for early afterglow phase. Here we investigate polarization evolution light curve under such three-dimensional field. Three kinds (i.e., aligned, toroidal, radial) are discussed. We find that...
As the standard gamma-ray burst (GRB) prompt-emission model, internal shock (IS) model can reproduce fast-rise and slow-decay features of pulses in GRB light curve. The time- energy-dependent polarization deliver important physical information on emission region be used to test models. Polarization predictions for prompt phase with magnetized IS should investigated carefully. magnetic field is very likely mixed decays radius. synchrotron presence such a decaying recover Band-like spectrum...
Abstract In addition to the light curve and energy spectrum, polarization is also important for inferring physical properties of gamma-ray burst (GRB). Rotation angle (PA) with time will cause depolarization time-integrated degree. However, it has rarely been studied before. Here, we use a magnetic reconnection model large-scale ordered aligned field in emitting region study influence parameters on PA rotations GRB prompt phase. We find that half-opening jet θ j , observational V bulk...
Abstract The time-integrated polarization degree (PD) in the prompt optical band of a gamma-ray burst (GRB) was predicted to be less than 20%, while time-resolved one can reach as high 75% photosphere model. Polarizations during GRB phase have not previously been studied framework magnetic reconnection Here, three-segment power law energy spectrum is used reconstruct Stokes parameters Multiwavelength light curves and from MeV gamma rays are studied. We found that, depending mainly on jet...
The X-ray afterglows of almost one half gamma-ray bursts have been discovered to a shallow decay phase by the {\em Swift} satellite, whose origin remains mysterious. Two main models proposed explain this phase, relativistic wind bubbles (RWBs) and structured ejecta, which could originate from millisecond magnetars rapidly-rotating black holes, respectively. Based on these models, we here investigate polarization evolution in optical afterglows. We find that RWB model, significant bump degree...
The environment of gamma-ray burst (GRB) has an important influence on the evolution jet dynamics and its afterglow. Here we investigate afterglow polarizations in a stratified medium with equal arrival time surface (EATS) effect. Polarizations multi-band afterglows are predicted. effects parameters also investigated. We found influences EATS effect become for off-axis detections PD bumps move to later times Even magnetic field configurations, structure observational angles fixed,...
Abstract A central compact object (CCO; e.g., a black hole) with an accretion disk has been suggested as the common engine of various astrophysical phenomena, such gamma-ray bursts (GRBs), tidal disruption events (TDEs), and active galactic nuclei (AGNs). jet powered by system might precess due to misalignment angular momenta CCO disk. Some quasiperiodic behaviors observed in light curves these phenomena can be well interpreted within framework precessing model. In this paper, we study...
In the former studies, time evolution information is missed in deducing time-integrated polarizations of gamma-ray burst (GRB) prompt emission. Here, it considered and investigated through summation time-resolved ones. The statistical properties distribution polarization degree ($\Pi$) can be read from $q-\Pi$ curve, where $q\equiv\theta_V/\theta_j$. $\theta_V$ $\theta_j$ are observational jet half-opening angles, respectively. Hence, only curves studied. addition to a toroidal magnetic...
The time-integrated polarization degree (PD) at prompt optical band of gamma-ray burst (GRB) was predicted to be less than $20\%$, while the time-resolved one can reach as high $75\%$ in photosphere model. Polarizations during GRB phase had not been studied under framework magnetic reconnection Here, a three-segment power laws energy spectrum is used reconstruct Stokes parameters multi-wavelength light curves and from MeV gamma-rays are studied. We found depending mainly on jet dynamics...
Abstract The observed abrupt twice-90° rotations of the polarization angle (PA) in prompt phase gamma-ray bursts (GRBs) are difficult to understand within current one-emitting-shell models. Here, we apply a model with multiple emitting shells solve this new challenging problem. Two configurations large-scale ordered magnetic fields considered: toroidal and aligned. Together light curves spectral peak energy evolutions, PA GRB 170114A 160821A could be well interpreted multishell aligned field...
The observed twice abrupt ${90}^{\circ}$ rotations of the polarization angle (PA) in prompt phase gamma-ray bursts (GRBs) are difficult to be understandable within current one-emitting-shell models. Here, we apply a model with multiple emitting shells solve this new challenging problem. Two configurations large-scale ordered magnetic fields considered: toroidal and aligned. Together light curves spectral peak-energy evolutions, PA GRB 170114A 160821A could well interpreted multi-shell...
The multi-window observations, including the light curve and evolutions of spectral peak energy ($E_p$), polarization degree (PD) angle (PA), are used to infer model parameters predict time-integrated PD in gamma-ray burst (GRB) prompt phase. We select 23 GRBs co-detected by Fermi/GBM detectors (i.e., GAP, POLAR AstroSat). In our fitting, curve, $E_p$ PA interpreted simultaneously under synchrotron radiation ordered magnetic fields aligned-fields case toroidal-fields case). For bursts with...
In addition to the light curve and energy spectrum, polarization is also important for study of Gamma-ray burst (GRB) prompt emission. Rotation angle (PA) with time will cause depolarization time-integrated degree. However, it rarely studied before. Here, we use magnetic reconnection model a large-scale ordered aligned field in emitting region influence key parameters on PA rotations. We find that half-opening jet $\theta_{j}$, observational $\theta_{V}$, bulk Lorentz factor $\Gamma$ all...