Conveners
Pulsar Power in Physics and Astrophysics and Pulsars and Pulsar Systems at High Energies: Block 2
- Pak-Hin Thomas Tam (Sun Yat-sen University)
Description
Pulsars and pulsar systems are efficient particle accelerators. Young pulsars and millisecond pulsars accelerate particles to relativistic speeds in their magnetosphere, emitting gamma-rays seen by the Fermi Gamma-ray Space Telescope. At larger length scales, pulsar wind particles are re-accelerated at the termination shock, generating pulsar wind nebulae in radio, X-rays, up to gamma-ray energies. Recently, a group of middle-aged pulsars, notably Geminga, are seen to be surrounded by an even larger structure -- TeV halo, discovered by the HAWC detector. Understanding how particles are transported from the pulsar to TeV halo scales (i.e., from 10 km to 10 parsec) is an important question in pulsar physics and can have implications to cosmic-ray physics. In this session, related topics will be discussed in the context of both observational and theoretical aspects.
The HAWC gamma-ray observatory has discovered very extended TeV gamma-ray structures around two pulsars Geminga and B0656+14. The gamma-ray emission, with its size of tens of parsecs, is produced from high-energy electrons and positrons around these two nearby middle-aged pulsars. Morphology studies suggest that the diffusion in the vicinity of these two pulsars is 100 times slower than the...
The Crab Pulsar's radio emission is unusual, consisting predominantly of giant pulses, with durations of about a micro-second but structure down to the nano-second level, and brightness temperatures of up to $10^{37}\,$K. It is unclear how giant pulses are produced, but they likely originate near the pulsar's light cylinder, where corotating plasma approaches the speed of light. We report...
Magnetars are slowly rotating, young, and isolated neutron stars with surface dipole magnetic fields exceeding the quantum electrodynamic magnetic field limit. They exhibit highly energetic behavior, as in the case of soft-gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs). Recently, they have been studied with paramount interest by almost every modern X-ray telescope. Despite the...
A scenario for the formation of an isolated X-ray pulsar 1E161348-5055 with an anomalously long period of 6.7 hours is proposed. It is shown that this pulsar can be a descendant of a massive X-ray binary system, which disintegrated about 2000 years ago after a supernova explosion caused by the core collapse of a massive component. X-ray radiation of this object in the present epoch is...
We present a new, complementary method of pulsar timing, which explicitly tracks the evolution of the pulse frequency and frequency derivative using a hidden Markov model (HMM). The HMM incorporates both stochastic spin wandering (timing noise) and glitches.
We describe how this framework can be used to detect glitches through Bayesian model selection with minimal human intervention and low...
Radio pulsar glitches probe far-from-equilibrium processes involving stress accumulation and relaxation in neutron star interiors. Previous studies of glitch rates have focused on individual pulsars with as many recorded glitches as possible. In this work we analyze glitch rates using all available glitch data, including objects that have glitched never or once. We assume the glitch rate...
