Identifying the physical nature of Fast Radio Burst (FRB) emitters requires good localisation of more detections, and broadband studies enabled by real-time telescope combinations. I will present the results from our Apertif FRB survey (ALERT), focusing on what we learned so-far about the connection between FRBs and neutron stars. ALERT performed wide-field, fully coherent, real-time FRB...
The radio transient phenomenon of fast radio bursts (FRBs), extragalactic flashes of radio emission occurring on ~millisecond timescales, continues to defy a definitive explanation. Ongoing monitoring campaigns from dedicated radio transient surveys have provided a rich catalog that have spurred a wide variety of analysis of the FRB population as a whole as well as specific sources displaying...
I discuss the physical mechanism of fast radio bursts based on observational constraints and theoretical modeling. First, within the magnetar model of FRBs, I discuss mounting evidence of the magnetospheric origin of at least some bursts. I argue that FRBs can propagate within a dynamically distorted magnetosphere with relativistic particles. I present a mechanism involving inverse Compton...
The first repeating fast radio burst (FRB) was discovered in a dwarf host galaxy, and unveiled a surprising persistent radio source (PRS) co-located with the bursts and offset from its host center. At present, the prevailing progenitor model for this source invokes a young magnetar engine born from a superluminous supernova or long-duration gamma-ray burst based on their similar host...
The MeerKAT telescope owned and operated by SARAO in the Karoo in South Africa is a new radio telescope with outstanding properties for precision pulsar timing. The telescope comprises of 64x13.6m dishes with offset Gregorian feeds, enabling it to achieve a system equivalent flux density of less than 7 Jy over an octave of bandwidth from 856-1712 MHz. Unlike single dishes, interferometers can...
In this talk, I will review the current understanding of the origin of FRBs, highlighting persisting enigmas such as FRB locations, magneto-environment, and long-term periodicity. Additionally, I will propose searches for rare polarized propagation effects to understand FRB sources.
Pulsars and Fast Radio Bursts (FRB) are radio astronomy's most energetic and "fast" phenomena. They are both possibly from "neutron stars". In this talk, I will introduce some of my group and collaborators' pulsars and FRB research using the Five-hundred-meter Aperture Spherical Radio Telescope (FAST), from pulsar spin-kick geometry, emission geometry, relativistic spin precession in double...
At least some repeating FRBs are thought to occur in magnetars, and the similarity of magnetar activity to earthquakes and solar flares has been discussed in the literature. Here I present a brief review of studies on the occurrence times and energies of repeater FRBs and their correlations. I then report on our recent work based on the two-point correlation function. We found many notable...
FRBs and gravitational waves are the first coherent cosmic sources that exhibit interference effects. These open the window for direct FRB microlensing time delay measurement and gravitational wave diffractive lensing, enabling new direct measures of the cosmic geometry.
We started the Galactic Plane Pulsar Snapshot (GPPS) survey since 2020, and now have discovered more than 630 pulsars, including pulsars in more than 60 binaries. We found 4 NS-NS binary systems, and many NS-WD systems including the one with the shortest orbit period (53min) probably evolved from Low-Mass X-ray Binaries. We also find many interesting pulsars such as RRATs, and also detected...
In this talk I will review recent progress in understanding the complex multi-scale plasma physics of neutron star magnetospheres through the lens of first-principles particle-in-cell simulations. I will highlight pair production discharges near the stellar surface and radiative magnetic reconnection near and beyond the light cylinder. I will extensively discuss their role in powering the...
Active neutron stars generate kHz magnetospheric waves of two types: Alfvén and magnetosonic. As the waves propagate away from the star, they become strongly nonlinear and dissipative. Alfvén waves trigger magnetic reconnection and ejection of relativistic plasmoids. Magnetosonic waves form monster radiative shocks inside the magnetosphere and then launch ultrarelativistic blast waves...
Magnetic energy injected into the magnetar magnetosphere is carried by Alfven waves. The dynamics and interactions of Alfven waves are essential in understanding how magnetic energy can be converted into radiations and building theoretical models for magnetar bursts and fast radio bursts. In this talk, I will discuss the dynamics and interactions of Alfven waves, including conversion to fast...
A rapidly rotating and highly magnetized neutron star (i.e., magnetar) may be formed in extreme stellar explosions or binary compact star mergers. In observation, the implement of various high-cadence transient surveys has discovered a considerable number of unusual optical transients in the past decades, which are generally analogy to ordinary supernovae but usually distinct in their...
I will discuss 3-dimensional simulations of pinning and unpinning of individual vortices and speculate on what happens to them during a glitch. I will also discuss a very simple evolutionary models for pinned vorticity in spinning-down neutron stars, and show that vortex loops and "rivers" inside them arise quite naturally in such models.
Recent neutron star observations coupled with the theoretical understanding emerging of the role that quark degrees of freedom play in supporting neutron stars are providing a consistent picture of neutron star interiors. An important key is the finding by the NICER telescope that massive neutron stars have considerably larger radius than nuclear degrees of freedom alone can explain. I will...
I will discuss efforts to interpret recent multi-messenger observations of neutron stars using advances in theory and modeling. These studies have provided new insights into the sound speed in dense matter and low-temperature properties, such as its specific heat and transport phenomena. Neutron stars can also be excellent sites to look for dark matter. I will briefly discuss harnessing...
The spindown of isolated pulsars, both aligned and oblique, has been extensively studied over the past few decades. However, in some binary systems, the interaction of pulsar magnetosphere and the wind from the companion can alter the rate of pulsar spindown. In this study, we use the particle-in-cell method to measure the spindown of pulsars surrounded by relativistic winds from companion...
The discovery of GW170817 has significantly advanced our understanding of the high-density equation of state. In this poster, I will showcase our recent studies that involve constraining the hadron-quark phase transition using both the existing GW170817 data and future GW observations. The discussion will encompass the constraints derived not only from quasi-equilibrium tides, but also from...
The Five-hundred-meter Aperture Spherical radio Telescope (FAST), the largest single-dish telescope ever built , has been in operation for over three years. Motivated by the great Arecibo observatory, FAST achieves the best instantaneous sensitivity in deca-centimeter bands. FAST data have resulted in more than 300 peer-reviewed publications, including high-impact results such as 9on Nature,...
The discovery of Fast Radio Bursts (FRBs), bright flashes of millisecond duration, has been a major breakthrough in radio astronomy. Sufficiently close to the engine, electrons in the field of the FRB electromagnetic wave oscillate with relativistic velocities. In this regime, the propagation of FRBs is subject to non-linear effects, including modulation/filamentation instabilities. I will...
