A neutron star–white dwarf binary model for periodically active fast radio burst sources

ABSTRACT We propose a compact binary model with an eccentric orbit to explain periodically active fast radio burst (FRB) sources, where the system consists of a neutron star (NS) with strong dipolar magnetic fields and a magnetic white dwarf (WD). In our model, the WD fills its Roche lobe at periastron, and mass transfer occurs from the WD to the NS around this point. The accreted material may be fragmented into a number of parts, which arrive at the NS at different times. The fragmented magnetized material may trigger magnetic reconnection near the NS surface. The electrons can be accelerated to an ultrarelativistic speed, and therefore the curvature radiation of the electrons can account for the burst activity. In this scenario, the duty cycle of burst activity is related to the orbital period of the binary. We show that such a model may work for duty cycles roughly from 10 min to 2 d. For the recently reported 16.35-d periodicity of FRB 180916.J0158 + 65, our model does not naturally explain such a long duty cycle, since an extremely high eccentricity (e > 0.95) is required.

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A NEUTRON STAR–WHITE DWARF BINARY MODEL FOR REPEATING FAST RADIO BURST 121102

The Astrophysical Journal ◽

10.3847/2041-8205/823/2/l28 ◽

2016 ◽

Vol 823 (2) ◽

pp. L28 ◽

Cited By ~ 41

Author(s):

Wei-Min Gu ◽

Yi-Ze Dong ◽

Tong Liu ◽

Renyi Ma ◽

Junfeng Wang

Keyword(s):

Neutron Star ◽

Radio Burst ◽

White Dwarf ◽

Binary Model ◽

Fast Radio Burst

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AT2018kzr: the merger of an oxygen–neon white dwarf and a neutron star or black hole

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1822 ◽

2020 ◽

Vol 497 (1) ◽

pp. 246-262 ◽

Cited By ~ 3

Author(s):

J H Gillanders ◽

S A Sim ◽

S J Smartt

Keyword(s):

Black Hole ◽

Neutron Star ◽

White Dwarf ◽

Near Infrared ◽

Theoretical Work ◽

Rapid Decline ◽

Compact Binary ◽

Fe Content ◽

Short Time ◽

Infrared Triplet

ABSTRACT We present detailed spectroscopic analysis of the extraordinarily fast-evolving transient AT2018kzr. The transient’s observed light curve showed a rapid decline rate, comparable to the kilonova AT2017gfo. We calculate a self-consistent sequence of radiative transfer models (using tardis) and determine that the ejecta material is dominated by intermediate-mass elements (O, Mg, and Si), with a photospheric velocity of ∼12 000–14 500 $\rm {km}\, s^{-1}$. The early spectra have the unusual combination of being blue but dominated by strong Fe ii and Fe iii absorption features. We show that this combination is only possible with a high Fe content (3.5 per cent). This implies a high Fe/(Ni+Co) ratio. Given the short time from the transient’s proposed explosion epoch, the Fe cannot be 56Fe resulting from the decay of radioactive 56Ni synthesized in the explosion. Instead, we propose that this is stable 54Fe, and that the transient is unusually rich in this isotope. We further identify an additional, high-velocity component of ejecta material at ∼20 000–26 000 $\rm {km}\, s^{-1}$, which is mildly asymmetric and detectable through the Ca ii near-infrared triplet. We discuss our findings with reference to a range of plausible progenitor systems and compare with published theoretical work. We conclude that AT2018kzr is most likely the result of a merger between an ONe white dwarf and a neutron star or black hole. As such, it would be the second plausible candidate with a good spectral sequence for the electromagnetic counterpart of a compact binary merger, after AT2017gfo.

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Sub-second periodicity in a fast radio burst

10.21203/rs.3.rs-726646/v1 ◽

2021 ◽

Author(s):

Bridget C. Andersen ◽

Kevin Bandura ◽

Mohit Bhardwaj ◽

P. J. Boyle ◽

Charanjot Brar ◽

...

Keyword(s):

Neutron Star ◽

Binary System ◽

Radio Burst ◽

Radio Bursts ◽

Radio Waves ◽

Pulse Profile ◽

Intensity Mapping ◽

Giant Pulses ◽

Component Pulse ◽

Fast Radio Burst

Abstract The origin of fast radio bursts (FRBs), millisecond-duration flashes of radio waves that are visible at distances of billions of light-years, remains an open astrophysical question. Here we report the detection of the multi-component FRB 20191221A with the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst Project (CHIME/FRB), and the identification of a periodic separation of 216.8(1) ms between its components with a significance of 6.5 sigmas. The long (~ 3 s) duration and nine or more components forming the pulse profile make this source an outlier in the FRB population. We also report two additional FRBs, 20210206A and 20210213A, whose multi-component pulse profiles show some indication of periodic separations of 2.8(1) and 10.7(1) ms, respectively, suggesting the possible existence of a group of FRBs with complex and periodic pulse profiles. Such short periodicities provide strong evidence for a neutron-star origin of these events. Moreover, our detections favour emission arising from the neutron-star magnetosphere, as opposed to emission regions located further away from the star, as predicted by some models. Possible explanations for the observed periodicity include super-giant pulses from a neutron star that are possibly related to a magnetar outburst and interacting neutron stars in a binary system.

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Revisiting the neutron star-white dwarf binary model of FRB 121102

SCIENTIA SINICA Physica, Mechanica & Astronomica ◽

10.1360/sspma2017-00176 ◽

2017 ◽

Vol 48 (2) ◽

pp. 029501 ◽

Cited By ~ 1

Author(s):

YiQing LIN ◽

ZaiJun CHENG ◽

LiangQin GAN

Keyword(s):

Neutron Star ◽

White Dwarf ◽

Binary Model

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Fast radio burst source properties and curvature radiation model

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stx665 ◽

2017 ◽

Vol 468 (3) ◽

pp. 2726-2739 ◽

Cited By ~ 86

Author(s):

Pawan Kumar ◽

Wenbin Lu ◽

Mukul Bhattacharya

Keyword(s):

Radio Burst ◽

Radiation Model ◽

Burst Source ◽

Curvature Radiation ◽

Fast Radio Burst

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A black hole–white dwarf compact binary model for long gamma-ray bursts without supernova association

Monthly Notices of the Royal Astronomical Society Letters ◽

10.1093/mnrasl/sly014 ◽

2018 ◽

Vol 475 (1) ◽

pp. L101-L105 ◽

Cited By ~ 6

Author(s):

Yi-Ze Dong ◽

Wei-Min Gu ◽

Tong Liu ◽

Junfeng Wang

Keyword(s):

Black Hole ◽

White Dwarf ◽

Gamma Ray ◽

Gamma Ray Bursts ◽

Compact Binary ◽

Binary Model

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Acoustic-Reflex Dynamics for Pulsed Signals

Journal of Speech and Hearing Research ◽

10.1044/jshr.2102.295 ◽

1978 ◽

Vol 21 (2) ◽

pp. 295-308

Author(s):

Terry L. Wiley ◽

Raymond S. Karlovich

Keyword(s):

Duty Cycle ◽

Acoustic Impedance ◽

Normal Hearing ◽

Broadband Noise ◽

Threshold Shift ◽

Temporary Threshold Shift ◽

Acoustic Reflex ◽

Stapedius Muscle ◽

Duty Cycles

Contralateral acoustic-reflex measurements were taken for 10 normal-hearing subjects using a pulsed broadband noise as the reflex-activating signal. Acoustic impedance was measured at selected times during the on (response maximum) and off (response minimum) portions of the pulsed activator over a 2-min interval as a function of activator period and duty cycle. Major findings were that response maxima increased as a function of time for longer duty cycles and that response minima increased as a function of time for all duty cycles. It is hypothesized that these findings are attributable to the recovery characteristics of the stapedius muscle. An explanation of portions of the results from previous temporary threshold shift experiments on the basis of acoustic-reflex dynamics is proposed.

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