Search

In general, giant flares (GFs) produced by magnetars have a very short-hard initial spike that is followed by a weak oscillatory phase. GFs from a nearby galaxy would appear as cosmic short-hard gamma-ray bursts (GRBs), such as GRB 200415A. In this paper, we search for GF-originated bursts in the Fermi GRB category and report GRB 210410A, which is presented with a very short-hard spike followed by an extended tail emission. In the E p, z − E iso plane, GRB 210410A with a duration of T 90 ∼ 48 s differs from long GRBs, might be classified as a short GRB with a redshift of z ∼ 0.28, and could be regarded as a GF with a distance of ∼2.7 Mpc. Here, E p, z , E iso, and L iso denote the rest-frame peak photon energy, the isotropic energy, and the isotropic luminosity of the burst, respectively. The radiation spectrum of GRB 210410A, similar to that of GRB 200415A, can be well fitted with a non-dissipative photospheric emission. However, GRB 210410A in the E p, z − L iso plane is beyond the death line of cosmic GRBs for non-dissipated photospheric emission with a general initial size of the fireball. Since the E p, z − L iso relation of GFs is far beyond the death line of cosmic GRBs, GRB 210410A may have originated from the same channel that produces GFs. We also perform the analysis and discuss both the highest photon energy event (4.2 GeV) and the extended tail emission in this burst. [ABSTRACT FROM AUTHOR]

Ultra-long-duration gamma-ray burst GRB 111209A was found to be associated with a very luminous supernovae (SNe) SN 2011kl. The physics of GRB 111209A/SN 2011kl has been extensively studied in the literature, but such research has not yet settled down. By investigating in detail the characteristics of the X-ray light curve of GRB 111209A, coupled with the temporal and spectral features observed in SN 2011kl, we argue that a short-lived supramassive magnetar could be responsible for the initial shallow X-ray emission. Then the electromagnetic extraction of spin energy from a black hole (BH) results in the steeply declining X-ray flux when the magnetar collapses into a BH. A fraction of the envelope materials falls back and activates the accretion onto the newborn BH, which produces the X-ray rebrightening bump at late times. During this process, a centrifugally driven baryon-rich quasi-isotropic Blandford & Payne outflow from the revived accretion disk deposits its kinetic energy on the SN ejecta, which powers luminous SN 2011kl. Finally, we place a limitation on the magnetar's physical parameters based on the observations. [ABSTRACT FROM AUTHOR]