Evidence of X-ray plateaus driven by the magnetar spindown winds in gamma-ray burst afterglows

Abstract

The central engine of gamma-ray bursts (GRBs) remains an open and forefront topic in the era of multimessenger astrophysics. The X-ray plateaus appear in some GRB afterglows, which are widely considered to originate from the spindown of magnetars. According to the stable magnetar scenario of GRBs, an X-ray plateau and a decay phase as ∼ t −2 should appear in X-ray afterglows. Meanwhile, the "normal" X-ray afterglow is produced by the external shock from GRB fireball. We analyze the Neil Gehrels Swift GRB data, then find three gold samples, which have an X-ray plateau and a decay phase as ∼ t −2 superimposed on the jet-driven normal component. Based on these features of the lightcurves, we argue that the magnetars should be the central engines of these three GRBs. Future joint multimessenger observations might further test this possibility, then which can be beneficial to constrain GRB physics.