Evolution of superhigh magnetic fields of magnetars

Gao, Zhi; Wang, Na; Yuan, Jianping; Jiang, Luhua; Song, D. L.; Qiao, Erlin

doi:10.1007/s10509-011-0664-3

Cited by 16 publications

(13 citation statements)

References 34 publications

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“…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 2013, 2015, 2016, 2017, 2019a, 2019b, 2021).…”

Section: Discussionsupporting

confidence: 61%

The fundamental plane of black hole activity for quiescent sources

Dong

Liu

et al. 2021

Astron Nachr

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In this work, we construct a sample of black hole X-ray binaries (BH XRBs), low-luminosity active galactic nuclei (LLAGNs), and FR Is with wider distribution of Eddington ratios and re-explore their fundamental plane of BH activities, that is, log L R = X log L X + M log L M BH + c 0. We find that the quiescent BH sources follow a similar fundamental plane (ξ X ∼ 0.6) with sub-Eddington BH sources very well, while the strong radio sources (e.g., FR Is) follow a steeper fundamental plane (ξ X ∼ 1.30). We also find that the radio-X-ray correlation of quiescent BH sources are still on the extension of sub-Eddington BH sources and the strong radio sources follow a steeper correlation (ξ X ∼ 1.30). The results are consistent with recent observations in BH XRBs. It is predicted that the X-ray emissions of both sub-Eddington BH sources and quiescent BH sources originate from radiatively inefficient accretion mode, while the X-ray emissions of strong radio sources dominantly originate from the jet.

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Section: Discussionsupporting

confidence: 61%

The fundamental plane of black hole activity for quiescent sources

Dong

Liu

et al. 2021

Astron Nachr

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“…Moreover, when investigating solar flare using this model, apart from the difficulty in explaining such a high energy transformation efficiency, there are also many other problems to be settled at present. According to the above analysis, the α − dynamo is still just a hypothesis (Gao et al 2011b;Hurley et al 2005;Mereghetti 2008;Vink and Kuiper 2006).…”

Section: Introductionmentioning

confidence: 96%

The Landau level-superfluid modified factor and the overal soft X/γ-ray efficiency coefficient of a magnetar

Gao

Peng

Wang

et al. 2011

Astrophys Space Sci

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As soon as the energies of electrons near the Fermi surface exceed Q, the threshold energy of inverse β-decay, electron capture (EC) dominates inside a neutron star. The high-energy neutrons released by EC will destroy anisotropic 3 P 2 neutron Cooper pairs in the degenerate superfluid. By colliding with the neutrons produced in the process n + (n ↑ n ↓) → n + n + n, the kinetic energies of the neutrons released by EC will be transformed into thermal energy. A portion of this thermal energy will be transported from the star interior to the star surface by conduction, then converted to a thermal spectrum of soft X-rays and γ -rays. By introducing two important parameters: the Landau levelsuperfluid modified factor and the overal soft X/γ -ray efficiency coefficient, we compute the theoretical luminosity L X of a magnetar under our model and plot a diagram of L X as a function of magnetic field strength B. Numerical calculations based on our model agree well with the observed properties of magnetar candidates.

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“…An equation of state (EoS) of matter under exotic conditions is a prerequisite for studies of the structure and evolution of compact stars. As an extremely interesting and important physical parameter in NS EoS, the electron fraction Y e influences the weak‐interaction processes, for example, modified Urca reactions, α ‐decay, electron capture, the absorption of neutrinos and anti‐neutrinos, and so on (see Yakovlev et al ; Dong et al , ; Gao et al , ; Liu & Liu , ; Liu et al , ; Sun et al ; Cheng et al , , ). The electron fraction Y e is defined as Y e = n e / n B , and varies with matter density, where n e and n B are the electron number density and baryon number density, respectively.…”

Section: Introductionmentioning

confidence: 99%

Reinvestigation of the electron fraction and electron Fermi energy of neutron star

et al. 2017

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In this work, we reinvestigate the electron fraction Ye and electron Fermi energy EF(e) of neutron stars, based on our previous work, in which we first deduce a special solution to EF(e), and then obtain several useful analytical formulae for Ye and matter density ρ within classical models and the relativistic mean‐field (RMF) theory using numerical fitting. The advantages of this formalism include the following: (a) Linear functions are substituted for the nonlinear exponential functions used in the previous work. This method may be simpler and closer to realistic equation of state (EoS) of a neutron star (NS) because there are linear or quasi‐linear relationships between number fractions of leptons and matter density, which can be seen by solving NS EoS. (b) We introduce a dimensionless variable ϱ (ϱ = ρ/ρ0, ρ0 is the standard saturated nuclear density), which greatly reduces the scope of the fitting coefficients. (c) We present numerical errors including absolute and relative deviations between the data and fit. By numerical simulations, we obtain several analytical formulae for Ye and ρ for both APR98 and RMF models. Combining these analytical formulae with the special solution, we can calculate the value of EF(e) for any given matter density. Since Ye and EF(e) are important in assessing the cooling rate of an NS and the possibility of kaon/pion condensation in the NS's interior, this formalism could be useful in the future studies on the thermal evolution of an NS.

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Evolution of superhigh magnetic fields of magnetars

Cited by 16 publications

References 34 publications

The fundamental plane of black hole activity for quiescent sources

The fundamental plane of black hole activity for quiescent sources

The Landau level-superfluid modified factor and the overal soft X/γ-ray efficiency coefficient of a magnetar

Reinvestigation of the electron fraction and electron Fermi energy of neutron star

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