C. Y. Hui — Page 6 | Searcharxiv

arXiv2006

Searches for diffuse X-ray emission around millisecond pulsars: An X-ray nebula associated with PSR J2124-3358

We report on diffuse X-ray emission associated with the nearby solitary millisecond pulsar PSR J2124-3358 detected with XMM-Newton and Chandra. The emission extends from the pulsar to the northwest by ~0.5 arcmin. The spectrum of the nebular emission can be modeled with a power-law of photon index $2.2\pm0.4$, in line with the emission originating from accelerated particles in the post shock flow. For PSR J0437-4715, PSR J0030+0451 and PSR J1024-0719, which all have spin parameters comparable to that of PSR J2124-3358, no diffuse emission is detected down to a 3-sigma limiting flux of $4-7\times10^{-15}$ ergs s$^{-1}$ cm$^{-2}$.

astro-ph↗

arXiv2004

The Effects of Rotation on Thermal X-Ray Afterglows Resulting from Pulsar Glitches

We derive the anisotropic heat transport equation for rotating neutron stars and the thermal equilibrium condition in a relativistic rotating axisymmetric star is also derived through a simple variational argument. With a simple model of neutron star, we model the propagation of heat pulses resulting from transient energy releases inside the star. {\bf Such sudden energy release can occur in pulsars during glitches.} Even in slow rotation limit ($Ω\leq 1\times 10^{3}{s}^{-1}$), the results with rotational effects involved could be noticeably different from those obtained with a spherically symmetric metric in terms of the time scales and magnitudes of thermal afterglow. The effects of gravitational lensing and frame dragging on the X-ray light curve pulsations are also studied. The results we obtain indicate that the effect of rotation on the light curve modulation is small, and the spacetime curvature effect predominates. The metric components and rotational deformation on the stellar structure are calculated by using Hartle-Thorne formalism. {\bf We have applied our model to study the thermal response time scales of pulsars after glitches and find that the centrifugal force produced by rotation can substantially reduce the response time by a factor of three between non-rotating star and rotating star with $Ω\sim 900 s^{-1}$. The equation of state can also affect the duration of response.

astro-ph↗

arXiv2003

Anisotropic Heat Transfer inside Rotating Neutron Stars

We have developed the anisotropic heat transport equation for rotating neutron stars. With a simple model of neutron star, we also model the propagation of heat pulses result from transient energy releases inside the star. Even in slow rotation limit, the results with rotational effects involved could differ significantly from those obtained with a spherically symmetric metric in the time scale of the thermal afterglow.

astro-ph↗