The dissipation of toroidal magnetic fields and spin‐down evolution of young and strongly magnetized pulsars

Abstract

Magnetars are a kind of pulsars powered mainly by superhigh magnetic fields. They are popular sources with many unsolved issues in themselves but are also linked to various high-energy phenomena, such as quasi periodic oscillations (QPOs), giant flares, fast radio bursts, and superluminous supernovae. In this work, we first review our recent works on the dissipation of toroidal magnetic fields in magnetars and rotationally powered pulsars and then review the spin-down evolution of young and strongly magnetized pulsars, especially of magnetars. We present an interesting and important relation between the magnetization parameter and magnetic field in the magnetar crust. Finally, we introduce our two works in progress: to explain the magnetar "antiglitch" events in the thermal plastic flow model and to revisit the expression of braking index n, which is independent of the second derivative of spin frequency of a pulsar, and give some proposals for our future work.

The fundamental plane of black hole activity for quiescent sources

“…It is predicted that the X-ray emissions in both sub-Eddington sources and quiescent sources originate from radiatively inefficient accretion flow (e.g., ADAF). We also find that the strong radio sources normally follow a steeper radio-X-ray correlation and fundamental plane of BH activity and predict that the X-ray emission of strong radio sources is mainly emitted from the jet (see also, de Gasperin et al 2011;Gao et al 2011b;Xie & Yuan 2017;Gao et al 2013Gao et al , 2015Gao et al , 2016Gao et al , 2017Gao et al , 2019aGao et al , 2019bGao et al , 2021.…”

On the fractional glitch recoveries and pulsar spin properties

“…by rotation powered pulsars, the other four pulsars are mostly magnetars and high-B rotation powered pulsars with magnetar-like behaviors. As we know, magnetars are mostly young pulsars powered by the decay of their conspicuous magnetic field (Gao et al 2016(Gao et al , 2017(Gao et al , 2019. It is discussed in detail in Section 4.…”

“…Ordinarily with respect to a rotation powered pulsar with a similar characteristic age, glitches in magnetars should be smaller compared to what is observed, as such, there could be a contribution of magnetospheric activity to their glitch sizes (Dib et al 2008; Yuan et al 2010). For magnetars, the glitch is usually accompanied with a burst or a flare and an excessive recovery could occur in the post‐glitch state, due to the dissipation of superhigh multiple magnetic fields (Gao et al 2021; H. Wang et al 2020; Yan et al 2021). Although the physics of such over‐recovery is still not very clear, several possibilities or models were put forward by several authors to explain the cause of over‐recovery in magnetars and high‐B rotation powered pulsars.…”

Equation of state and surface thermal emission of magnetized white dwarfs

“…This paper aims to establish a coupled magnetothermal evolution model for B-WDs, based on our previous study on the neutron star magnetic field evolution (Gao et al , 2017(Gao et al , 2021Wang et al 2019Wang et al , 2020Wang et al , 2021. The specific methods include introducing the magnetic-to-thermal conversion coefficient, combining the Ohmic dissipation and Hall drift, and considering the influence of the central temperature on the stellar radius.…”