Strongly screened electron capture rates of chromium isotopes in presupernova evolution

Liu, Jingjing; Peng, Qiu‐He; Hao, Liang; Kang, Xiao-Ping; Li, Dongmei

doi:10.1088/1674-4527/17/10/107

Cited by 14 publications

(8 citation statements)

References 17 publications

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“…Ordinarily with respect to a rotationpowered pulsar with a similar characteristic age, glitches in magnetars should be smaller compared to what is observed. Magnetars are mostly young pulsars powered by the decay of their conspicuous magnetic field rather than the loss of their rotational energy (Gao et al 2013;Zhu et al 2016;Liu et al 2017); as such, there could be a contribution of magnetospheric activity to their glitch sizes (Gao et al 2016).…”

Section: Discussionmentioning

confidence: 99%

On the distributions of pulsar glitch sizes and the inter-glitch time intervals

Eya

Urama

Chukwude

2019

Res. Astron. Astrophys.

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The glitch size, ∆ν/ν, inter-glitch time interval, t i and frequency of glitches in pulsars are key parameters in discussing glitch phenomena. In this paper, the glitch sizes and inter-glitch time intervals were statistically analysed in a sample of 168 pulsars with a total of 483 glitches. The glitches were broadly divided into two groups. Those with ∆ν/ν < 10 −7 are regarded as small size glitches, while those with ∆ν/ν ≥ 10 −7 are regarded as relatively large size glitches. In the ensemble of glitches, the distribution of ∆ν/ν is seen to be bimodal as usual. The distribution of inter-glitch time intervals is unimodal and the inter-glitch time intervals between small and large size glitches are not significantly different from each other. This observation shows that inter-glitch time intervals are size independent. In addition, the distribution of the ratio ∆ν/ν : t i in both small and large size glitches has the same pattern. This observation suggests that a parameter which depends on time, which could be the spin-down rate of a pulsar plays a similar role in the processes that regulate both small and large size glitches. Equally this could be an indication that a single physical mechanism, which could produce varying glitch sizes at similar time-intervals could be responsible for both classes of glitch sizes.

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Section: Discussionmentioning

confidence: 99%

On the distributions of pulsar glitch sizes and the inter-glitch time intervals

Eya

Urama

Chukwude

2019

Res. Astron. Astrophys.

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“…The main reasons are twofold: (i) magnetars are a kind of special pulsar powered by their magnetic energy rather than their rotational energy (Duncan & Thompson 1992;Gao et al 2013;Liu et al 2017);and (ii) to account for the high-value braking indices of magnetars, we adopted the updated magnetothermal evolution model of Viganò et al (2013) (see Gao et al 2016.…”

Section: Comparisons With Our Previous Workmentioning

confidence: 99%

The Dipole Magnetic Field and Spin-down Evolutions of the High Braking Index Pulsar PSR J1640–4631

Gao

Wang

Shan

et al. 2017

ApJ

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In this work, we interpreted the high braking index of PSR J1640−4631 with a combination of the magnetodipole radiation and dipole magnetic field decay models. By introducing a mean rotation energy conversion coefficient z , the ratio of the total high-energy photon energy to the total rotation energy loss in the whole life of the pulsar, and combining the pulsar's high-energy and timing observations with a reliable nuclear equation of state, we estimate the pulsar's initial spin period, P 17 44 0~( -) ms, corresponding to the moment of inertia I 0.8 2.1 10 45( -) g cm 2 .Assuming that PSR J1640−4631 has experienced a long-term exponential decay of the dipole magnetic field, we calculate the true age t age , the effective magnetic field decay timescale D t , and the initial surface dipole magnetic field at the pole B 0 p ( ) of the pulsar to be 2900−3100 yr, 1.07 2 10 5 ( ) yr, and 1.84 4.20 10 13 ( -) G, respectively. The measured braking index of n 3.15 3 = ( ) for PSR J1640−4631 is attributed to its long-term dipole magnetic field decay and a low magnetic field decay rate, dB dt 1.66 3.85 10 p 8-( -) G yr −1 . Our model can be applied to both the high braking index (n 3 > ) and low braking index (n 3 < ) pulsars, tested by the future polarization, timing, and high-energy observations of PSR J1640−4631.

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“…As fossils of stellar evolution, radio pulsars are considered to be strongly gravitating, rapidly rotating, and strongly magnetized neutron stars (NSs), the products of massive stars evolving through supernova events. The spin periods of young radio pulsars have been observed to be decreasing (Liu et al ; Yan et al ; Zhao et al , ). A pulsar's secular spin‐down is probably caused by its rotational energy losses due to electromagnetic radiation, particle winds, intense neutrino emission, or gravitational radiation.…”

Section: Introductionmentioning

confidence: 99%

The evolution of magnetic field and spin‐down of young pulsars

2019

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Here, we summarize our recent work on the evolution of magnetic field and spin-down of young pulsars including high-B pulsars and magnetars. Our work includes the following three parts: (a) Based on the estimated ages of their potentially associated supernova remnants (SNRs), we estimate the values of the mean braking indices of eight magnetars with SNRs and find that five magnetars have smaller mean braking indices of 1 < n < 3, and we interpret them within a combination of magnetodipole radiation and wind-aided braking. (b) The low braking index of n = 0.9(2) for PSR J1734-3333 could undergo a supercritical accretion soon after its formation in a supernova explosion. The buried multipole magnetic fields will merge into a dipole magnetic field. Retaining the current field growth index = 1.34, this pulsar will become a magnetar with dB p ∼6.2(2) × 10 14 G and dB p ∼1.06(4) × 10 15 G after 50 kyrs and 100 kys, respectively. (c) By introducing a mean rotation energy conversion coefficient and combining the pulsar's high-energy and timing observations with a reliable nuclear equation of state, we estimate the initial spin period, initial dipole magnetic field, and true age of PSR J1640-4631. For this source, its measured high braking index n = 3.15(3) is attributed to a long-term dipole magnetic field decay, and its soft X-ray emission is attributed to anisotropic heating. K E Y W O R D SPSR J1640-4631, toroidal magnetic field, TPW heating

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Strongly screened electron capture rates of chromium isotopes in presupernova evolution

Cited by 14 publications

References 17 publications

On the distributions of pulsar glitch sizes and the inter-glitch time intervals

On the distributions of pulsar glitch sizes and the inter-glitch time intervals

The Dipole Magnetic Field and Spin-down Evolutions of the High Braking Index Pulsar PSR J1640–4631

The evolution of magnetic field and spin‐down of young pulsars

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