Shengnan Sun | Searcharxiv

arXiv2024

The Study of Mode Switching behavior of PSR J0614+2229 Using the Parkes Ultra-wideband Receiver Observations

In this paper, we presented a detailed single pulse and polarization study of PSR J0614+2229 based on the archived data observed on 2019 August 15 (MJD 58710) and September 12 (MJD 58738) using the Ultra-wideband Low-frequency Receiver on the Parkes radio telescope. The single-pulse sequences show that this pulsar switches between two emission states, in which the emission of state A occurs earlier than that of state B in pulse longitude. We found that the variation in relative brightness between the two states is related to time and both states follow a simple power law very well. Based on the phase-aligned multi-frequency profiles, we found that there is a significant difference in the distributions of spectral index across the emission regions of the two states. Furthermore, we obtained the emission height evolution for the two emission states and found that, at a fixed frequency, the emission height of state A is higher than that of state B. What is even more interesting is that the emission heights of both states A and B have not changed with frequency. Our results suggest that the mode switching of this pulsar is possibly caused by changes in the emission heights that alter the distributions of spectral index across the emission regions of states A and B resulting in the frequency-dependent behaviors, i.e., intensity and pulse width.

astro-ph.HE↗

arXiv2018

On Isolated Millisecond Pulsars Formed by the Coalescence of Neutron Stars and Massive White Dwarfs

This paper uses population synthesis to investigate the possible origin of isolated millisecond pulsars (IMSPs) as born from the coalescence of a neutron star (NS) and a white dwarf (WD). Results show that the galactic birth - rate of IMSPs is likely to lie between $5.8\times10^{-5}$ $\rm yr^{-1}$ and $2.0\times10^{-4}$ $\rm yr^{-1}$, depending on critical variables, such as the stability of mass transfer via the Roche lobe and the value of kick velocity. In addition to this, this paper estimates that the solar mass of IMSPs can range from $1.5$ and 2.0 $M_{\odot}$, making them more massive than other 'normal' pulsars. Finally, the majority of IMSPs in our simulations have spin periods ranging from several to 20 milliseconds, which is consistent with previous observations.

astro-ph.HE↗