| Autor: |
Piro, L, Troja, E, Zhang, B, Ryan, G, van Eerten, H, Ricci, R, Wieringa, M H, Tiengo, A, Butler, N R, Cenko, S B, Fox, O D, Khandrika, H G, Novara, G, Rossi, A, Sakamoto, T |
| Předmět: |
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| Zdroj: |
Monthly Notices of the Royal Astronomical Society; Feb2019, Vol. 483 Issue 2, p1912-1921, 10p |
| Abstrakt: |
Multimessenger observations of GW170817 have not conclusively established whether the merger remnant is a black hole (BH) or a neutron star (NS). We show that a long-lived magnetized NS with a poloidal field B ≈ 1012 G is fully consistent with the electromagnetic dataset, when spin-down losses are dominated by gravitational wave (GW) emission. The required ellipticity ε ≳ 10−5 can result from a toroidal magnetic field component much stronger than the poloidal component, a configuration expected from an NS newly formed from a merger. Abrupt magnetic dissipation of the toroidal component can lead to the appearance of X-ray flares, analogous to the one observed in gamma-ray burst (GRB) afterglows. In the X-ray afterglow of GW170817, we identify a low-significance (≳3σ) temporal feature at 155 d, consistent with a sudden reactivation of the central NS. Energy injection from the NS spin-down into the relativistic shock is negligible, and the underlying continuum is fully accounted for by a structured jet seen off-axis. Whereas radio and optical observations probe the interaction of this jet with the surrounding medium, observations at X-ray wavelengths, performed with adequate sampling, open a privileged window on to the merger remnant. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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