DOI:
10.1051/0004-6361/201730578
Authors:
Knust, F.;Greiner, J.;van Eerten, H. J.;Schady, P.;Kann, D. A.;Chen, T. -W.;Delvaux, C.;Graham, J. F.;Klose, S.;Krühler, T.;McConnell, N. J.;Nicuesa Guelbenzu, A.;Perley, D. A.;Schmidl, S.;Schweyer, T.;Tanga, M.;Varela, K.
Journal:
Astronomy and Astrophysics
Abstract:
Context. Short-duration gamma-ray bursts (GRBs) with extended emission form a subclass of short GRBs, comprising about 15% of the short-duration sample. Afterglow detections of short GRBs are also rare (about 30%) because of their lower luminosity. <BR /> Aims: We present a multiband data set of the short burst with extended emission, GRB 150424A, comprising of GROND observations, complemented with data from Swift/UVOT, Swift/XRT, HST, Keck/LRIS, and data points from the literature. The GRB 150424A afterglow shows an extended plateau phase, lasting about 8 h. The analysis of this unique GRB afterglow might shed light on the understanding of afterglow plateau emission, the nature of which is still under debate. <BR /> Methods: We present a phenomenological analysis made by applying fireball closure relations and interpret the findings in the context of the fireball model. We discuss the plausibility of a magnetar as a central engine, which would be responsible for additional and prolonged energy injection into the fireball. <BR /> Results: We find convincing evidence for energy injection into the afterglow of GRB 150424A. We find that a magnetar spin-down as the source for a prolonged energy injection requires that at least 4% of the spin-down energy is converted into radiation.
URL:
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85034838101&doi=10.1051%2f0004-6361%2f201730578&partnerID=40&md5=c764558f3a900a0c9ee2ba37e8545cbe
Keywords:
gamma-ray burst: general;gamma-ray burst: individual: 150424A;methods: observational;methods: data analysis