Electromagnetic emission from newly born magnetar spin-down by gravitational-wave and magnetic dipole radiations

Lü, Hou-Jun; Zou, Le; Lin, Li; Liang, En‐Wei

doi:10.1093/mnras/sty2176

Cited by 38 publications

(44 citation statements)

References 70 publications

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“…We estimate the P 0 and B p values for those sGRBs and lGRBs in our sample with n < 3 or n ∼ 3 within its error bars (e.g. Zhang & Mészáros 2001;Lü et al 2018),…”

Section: Initial Spin Period and Magnetic Field Strengthmentioning

confidence: 64%

“…For example, the alignment and magnetic dipole moment decline and the fall-back accretion of a newborn magnetar should result in the evolutions of the braking index and spin period in the early stage (e.g. Mészáros 2001;Fan et al 2013;Giacomazzo & Perna 2013;Lasky & Glampedakis 2016;Lü et al 2018;Metzger et al 2018;S ¸aşmaz Muş et al 2019).…”

Section: Spin Down Mechanisms Of Newborn Magnetarsmentioning

confidence: 99%

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Comparison of the Characteristics of Magnetars Born in Death of Massive Stars and Merger of Compact Objects With {\em Swift} Gamma-Ray Burst Data

Zou,

Liang,

Zhong

et al. 2021

Preprint

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Assuming that the shallow-decaying phase in the early X-ray lightcurves of gamma-ray bursts (GRBs) is attributed to the dipole radiations (DRs) of a newborn magnetar, we present a comparative analysis for the magnetars born in death of massive stars and merger of compact binaries with long and short GRB (lGRB and sGRB) data observed with the Swift mission. We show that the typical braking index (n) of the magnetars is ∼ 3 in the sGRB sample, and it is ∼ 4 for the magnetars in the lGRB sample. Selecting a sub-sample of the magnetars whose spin-down is dominated by DRs (n 3) and adopting a universal radiation efficiency of 0.3, we find that the typical magnetic field strength (B p ) is 10 16 G vs. 10 15 G and the typical initial period (P 0 ) is ∼ 20 ms vs. 2 ms for the magnetars in the sGRBs vs. lGRBs. They follow the same relation between P 0 and the isotropic GRB energy as P 0 ∝ E −0.4 jet . We also extend our comparison analysis to superluminous supernovae (SLSNe) and stable pulsars. Our results show that a magnetar born in merger of compact stars tends to have a stronger B p and a longer P 0 by about one order of magnitude than that born in collapse of massive stars. Its spin-down is dominated by the magnetic DRs as old pulsars, being due to its strong magnetic field strength, whereas the early spin-down of magnetars born in massive star collapse is governed by both the DRs and gravitational wave (GW) emission. A magnetar with a faster rotation speed should power a more energetic jet, being independent of its formation approach.

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“…We estimate the P 0 and B p values for those sGRBs and lGRBs in our sample with n < 3 or n ∼ 3 within its error bars (e.g. Zhang & Mészáros 2001;Lü et al 2018),…”

Section: Initial Spin Period and Magnetic Field Strengthmentioning

confidence: 64%

Section: Spin Down Mechanisms Of Newborn Magnetarsmentioning

confidence: 99%

Comparison of the Characteristics of Magnetars Born in Death of Massive Stars and Merger of Compact Objects With {\em Swift} Gamma-Ray Burst Data

Zou,

Liang,

Zhong

et al. 2021

Preprint

Self Cite

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“…Moreover, one can obtain the transition time (τ * ) which point is from GW dominated to EM dominated emission (Zhang & Mészáros 2001;Lasky & Glampedakis 2016;Lü et al 2018),…”

Section: Physical Interpretation With Magnetar Central Enginementioning

confidence: 99%

Evidence for Gravitational-wave-dominated Emission in the Central Engine of Short GRB 200219A

Lü

Yuan

Lin

et al. 2020

ApJL

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GRB 200219A is a short gamma-ray burst (GRB) with an extended emission (EE) lasting ∼ 90s. By analyzing data observed with the Swift/BAT and Fermi/GBM, we find that a cutoff power-law model can adequately fit the spectra of the initial short pulse with E p = 1387 +232 −134 keV. More interestingly, together with the EE component and early X-ray data, it exhibits plateau emission smoothly connected with a ∼ t −1 segment and followed by an extremely steep decay. The short GRB composed of those three segments is unique in the Swift era and is very difficult to explain with the standard internal/external shock model of a black hole central engine, but could be consistent with the prediction of a magnetar central engine from the merger of an NS binary. We suggest that the plateau emission followed by a ∼ t −1 decay phase is powered by the spin-down of a millisecond magnetar, which loses its rotation energy via GW quadrupole radiation. Then, the abrupt drop decay is caused by the magnetar collapsing into a black hole before switching to EM-dominated emission. This is the first short GRB for which the X-ray emission has such an intriguing feature powered by a magnetar via GW-dominated radiation. If this is the case, one can estimate the physical parameters of a magnetar, the GW signal powered by a magnetar and the merger-nova emission are also discussed.

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“…In principle, the physical parameters of the newly born magnetar could be estimated by fitting the observed GRB X-ray plateau data. On the other hand, one can also infer the dominant energy loss term (EM or GW radiation) by analyzing the braking index of the magnetar, which can be obtained by fitting the decay slopes of the X-ray plateau and its follow-up segment (Zhang & Mészáros 2001;Lasky & Glampedakis 2016;Lasky et al 2017;Lü et al 2018Lü et al , 2019. Studying the population of braking indices is another feasible way to look at this (Sarin et al 2020a).…”

Section: Introductionmentioning

confidence: 99%

The evolution effects of radius and moment of inertia for rapidly rotating neutron stars

Lan,

Gao,

et al. 2021

Preprint

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A newly born millisecond magnetar is thought to be the central engine of some gamma-ray bursts (GRBs), especially those that present long-lasting X-ray plateau emissions. By solving the field equations, we find that when the rotational speed of the magnetar is approaching the breakup limit, its radius R and moment of inertia I would undergo an obvious evolution as the magnetar spins down. Meanwhile, the values of R and I would sensitively depend on the adoption of neutron star (NS) equation of state (EoS) and the NS baryonic mass. With different EoSs and baryonic masses considered, the magnetic dipole radiation luminosity (L dip ) could be variant within one to two orders of magnitude. We thus suggest that when using the X-ray plateau data of GRBs to diagnose the properties of the nascent NSs, EoS and NS mass information should be invoked as simultaneously constrained parameters. On the other hand, due to the evolution of R and I, the temporal behavior of L dip would become more complicated. For instance, if the spin-down process is dominated by gravitational wave emission due to the NS asymmetry caused by magnetic field distortion (ǫ ∝ B 2 p ), the segment L dip ∝ t 0 could be followed by L dip ∝ t −γ with γ larger than 3. This case could naturally interpret the so-called internal X-ray plateau feature shown in some GRB afterglows, which means the sharp decay following the plateau is unnecessarily corresponding to the NS collapsing. This may explain why some internal X-ray plateaus are followed by late time central engine activity, manifested through flares and second shallow plateaus.

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Electromagnetic emission from newly born magnetar spin-down by gravitational-wave and magnetic dipole radiations

Cited by 38 publications

References 70 publications

Comparison of the Characteristics of Magnetars Born in Death of Massive Stars and Merger of Compact Objects With {\em Swift} Gamma-Ray Burst Data

Comparison of the Characteristics of Magnetars Born in Death of Massive Stars and Merger of Compact Objects With {\em Swift} Gamma-Ray Burst Data

Evidence for Gravitational-wave-dominated Emission in the Central Engine of Short GRB 200219A

The evolution effects of radius and moment of inertia for rapidly rotating neutron stars

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