Magnetic Field Effects on Pulsars

Dr Ng, Stephen Chi Yung   (Principal Investigator (PI))

Dr Wang Zhongxiang   (Co-Investigator)

Professor Cumming Andrew   (Co-Investigator)

Professor Kaspi Victoria M.   (Co-Investigator)

Dr Takata Jumpei   (Co-Investigator)

36

2016-01-01

501255

Magnetic Field Effects on Pulsars

magnetars, magnetic field, millisecond pulsars, pulsars, radiation process

Others - Physical Sciences

Physical Sciences (P)

17300215

General Research Fund (GRF)

2015

Completed

1 Comparing the surface temperature of magnetars and high-B RPPs: one major prediction of the magneto-thermal evolution model is that objects possess strong B-fields should show significant crustal heating resulting from field decay. This effect is expected to keep magnetars hotter for longer. We plan to test this with new X-ray observations of magnetars and RPPs. We will measure their surface temperature and compare quantitatively with theory predictions. The results will significantly expand the sample, as only a few strongly magnetized pulsars have temperature measurements so far. 2 Determining the physical conditions of magnetars and high-B RPPs from timing: the physical distinction between different pulsar classes could lie on the toroidal B-field component, which is not directly observable from spin down, but can give rise to complex pulse profiles. In order to test this theory, we will analyse the magnetars and high-B RPPs pulse profiles and quantify their complexity using a Fourier or wavelet technique. We will identify any correlations between the complexity and the surface temperature, field strength, and other physical parameters. Moreover, we will compile a database of magnetar glitches and carry out a statistical comparison with those of radio pulsars. The results will reveal effects of strong magnetic fields on pulsar interior structure. 3 Detecting magnetar emission at long wavelengths: four magnetars have radio pulsations detected, but the emission mechanism remains unclear. We propose new observations to measure the magnetar spectra at high radio frequency. This will fill in the gap between radio and infrared data and indicate any spectral turnover. The results will provide essential inputs for building a physical model. Also, detecting any correlated flux variabilities with emission at other wavelengths will localize the emission site to unveil the emission mechanism. 4 Measuring the hard X-ray spectra of MSPs: the strong magnetic fields at the light cylinders of MSPs result in short plasma instability timescales, which could lead to coherent radio emission in phase with gamma-ray pulsations. The radio waves would inverse-Compton scatter with energetic particles in the magnetosphere to produce X-rays. To test this idea, we propose new observations to measure the hard X-ray spectra of several MSPs. We will search for signatures of inverse-Compton emission. The results will make predictions to the low-frequency radio spectra, which can be tested with the on-going radio studies.