Related papers: Steep Decay Phase Shaped by the Curvature Effect. …
The curvature effect may be responsible for the steep decay phase observed in gamma-ray bursts. For testing the curvature effect with observations, the zero time point $t_0$ adopted to plot observer time and flux on a logarithmic scale…
We consider a relativistic spherical shell and calculate its spectral flux as received by a distant observer. Using two different methods, we derive a simple analytical expression of the observed spectral flux and show that the well-known…
Spectral evolution of gamma-ray burst pulses assumed to arise from emission of fireballs is explored. It is found that, due to the curvature effect, the integrated flux and peak energy are well related by a power law in the decaying phase…
The curvature effect is explored in the case of extremely short intrinsic emission. Assuming a $\delta$ function emission we get formulas that get rid of the impacts from the intrinsic emission duration, which are applicable to any forms of…
As a result of spherical kinematics, temporal evolution of received gamma-ray emission should demonstrate signatures of curvature from the emitting shell. Specifically, the shape of the pulse decay must bear a strict dependence on the…
Recent research shows that the spectral lag is closely related to the spectral evolution in GRBs. In this paper, we study the spectral lag for a radiating jet shell with a high-energy cut-off radiation spectrum. For the jet shell with a…
An elementary kinematic model for emission produced by relativistic spherical colliding shells is studied. The case of a uniform blast-wave shell with jet opening angle $\theta_j \gg 1/\Gamma$ is considered, where $\Gamma$ is the Lorentz…
The quasi-thermal components found in many Fermi gamma-ray bursts (GRBs) imply that the photosphere emission indeed contributes to the prompt emission of many GRBs. But whether the observed spectra empirically fitted by the Band function or…
Assuming an intrinsic `Band' shape spectrum and an intrinsic energy-independent emission profile we have investigated the connection between the evolution of the rest-frame spectral parameters and the spectral lags measured in gamma-ray…
We use the local curvature derived from velocity vector fields or particle tracks as a surrogate for structure size to compute curvature-based energy spectra. An application to homogeneous isotropic turbulence shows that these spectra…
We report results from an experiment designed to test the conserved vector current (CVC) hypothesis by measuring the shape of the $\beta$-decay spectrum for the allowed $0^+\rightarrow 1^+$ ground state decay of $^{14}$O. Measurements of…
Photons that decouple from a relativistic jet do so over a range of radii, which leads to a spreading in arrival times at the observer. Therefore, changes to the comoving photon distribution across the decoupling zone are encoded in the…
In the work, we explore the role of jet properties in the spectral evolution for a sample of Fermi-LAT bright blazars composed primarily by flat spectrum radio quasars (FSRQs). We introduce a near-equipartition log-parabola (NELP) model to…
The Lorentz factor of a relativistic jet and its evolution during the jet expansion are difficult to estimate, especially for the jets in gamma-ray bursts (GRBs). However, it is related to the understanding of jet physics. Owing to the…
We consider an analytical approach that involves the complex poles of the propagator to investigate the effect due to the lack of time reversal invariance on the time evolution of decay for purely absorptive potentials. We find that the…
The atomic exchange effect will lead to a significant increase in the probability density of $\beta$ decays below a few keV. This effect is very important for scientific experiments that performed by low-energy electron spectroscopy…
There is theoretical and observational evidence that the jet core position changes with frequency. However, the core position for a given frequency may vary with time in the case of flares or for a precessing jet. In this work, we want to…
We develop the theory of jitter radiation from GRB shocks containing small-scale magnetic fields and propagating at an angle with respect to the line of sight. We demonstrate that the spectra vary considerably: the low-energy photon index,…
We consider the energy spectrum of emitted electrons in $\beta$-decay. Exact Coulomb Dirac wave functions describing the $\beta$-electron in the Coulomb field of the daughter nucleus are used. Further, the improved wave functions which…
Solar flare accelerated electrons escaping into the interplanetary space and seen as type III solar radio bursts are often detected near the Earth. Using numerical simulations we consider the evolution of energetic electron spectrum in the…