TY - JOUR
T1 - The early evolution of magnetar rotation – II. Rapidly rotating magnetars
T2 - implications for gamma-ray bursts and superluminous supernovae
AU - Prasanna, Tejas
AU - Coleman, Matthew S.B.
AU - Raives, Matthias J.
AU - Thompson, Todd A.
N1 - Publisher Copyright:
© 2023 Oxford University Press. All rights reserved.
PY - 2023/12/1
Y1 - 2023/12/1
N2 - Rapidly rotating magnetars have been associated with gamma-ray bursts (GRBs) and superluminous supernovae (SLSNe). Using a suite of two-dimensional magnetohydrodynamic simulations at fixed neutrino luminosity and a couple of evolutionary models with evolving neutrino luminosity and magnetar spin period, we show that magnetars are viable central engines for powering GRBs and SLSNe. We also present analytical estimates of the energy outflow rate from the proto-neutron star (PNS) as a function of polar magnetic field strength B0, PNS angular velocity Ω*, PNS radius R*, and mass outflow rate M͘ . We show that rapidly rotating magnetars with spin periods P* ~< 4 ms and polar magnetic field strength B0 ~< 1015 G can release 1050 to 5 × 1051 erg of energy during the first ∼2 s of the cooling phase. Based on this result, it is plausible that sustained energy injection by magnetars through the relativistic wind phase can power GRBs. We also show that magnetars with moderate field strengths of B0 <~ 5 × 1014 G do not release a large fraction of their rotational kinetic energy during the cooling phase and, hence, are not likely to power GRBs. Although we cannot simulate to times greater than ∼3–5 s after a supernova, we can hypothesize that moderate field strength magnetars can brighten the supernova light curves by releasing their rotational kinetic energy via magnetic dipole radiation on time-scales of days to weeks, since these do not expend most of their rotational kinetic energy during the early cooling phase.
AB - Rapidly rotating magnetars have been associated with gamma-ray bursts (GRBs) and superluminous supernovae (SLSNe). Using a suite of two-dimensional magnetohydrodynamic simulations at fixed neutrino luminosity and a couple of evolutionary models with evolving neutrino luminosity and magnetar spin period, we show that magnetars are viable central engines for powering GRBs and SLSNe. We also present analytical estimates of the energy outflow rate from the proto-neutron star (PNS) as a function of polar magnetic field strength B0, PNS angular velocity Ω*, PNS radius R*, and mass outflow rate M͘ . We show that rapidly rotating magnetars with spin periods P* ~< 4 ms and polar magnetic field strength B0 ~< 1015 G can release 1050 to 5 × 1051 erg of energy during the first ∼2 s of the cooling phase. Based on this result, it is plausible that sustained energy injection by magnetars through the relativistic wind phase can power GRBs. We also show that magnetars with moderate field strengths of B0 <~ 5 × 1014 G do not release a large fraction of their rotational kinetic energy during the cooling phase and, hence, are not likely to power GRBs. Although we cannot simulate to times greater than ∼3–5 s after a supernova, we can hypothesize that moderate field strength magnetars can brighten the supernova light curves by releasing their rotational kinetic energy via magnetic dipole radiation on time-scales of days to weeks, since these do not expend most of their rotational kinetic energy during the early cooling phase.
KW - MHD
KW - gamma-ray bursts
KW - stars: magnetars
KW - transients: supernovae
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U2 - 10.1093/mnras/stad2948
DO - 10.1093/mnras/stad2948
M3 - Article
AN - SCOPUS:85175166429
SN - 0035-8711
VL - 526
SP - 3141
EP - 3155
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -