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How Much Can $^{56}$Ni Be Synthesized by Magnetar Model for Long Gamma-ray Bursts and Hypernovae?

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 نشر من قبل Yudai Suwa
 تاريخ النشر 2014
  مجال البحث فيزياء
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 تأليف Yudai Suwa




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A rapidly rotating neutron star with strong magnetic fields, called magnetar, is a possible candidate for the central engine of long gamma-ray bursts and hypernovae (HNe). We solve the evolution of a shock wave driven by the wind from magnetar and evaluate the temperature evolution, by which we estimate the amount of $^{56}$Ni that produces a bright emission of HNe. We obtain a constraint on the magnetar parameters, namely the poloidal magnetic field strength ($B_p$) and initial angular velocity ($Omega_i$), for synthesizing enough $^{56}$Ni mass to explain HNe ($M_{^{56}mathrm{Ni}}gtrsim 0.2M_odot$), i.e. $(B_p/10^{16}~mathrm{G})^{1/2}(Omega_i/10^4~mathrm{rad~s}^{-1})gtrsim 0.7$.



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