* Astronomy

Title: Superluminous Supernova iPTF13ehe: First Evidence of Triple Energy Sources
Author: S. Q. Wang, L. D. Liu, Z. G. Dai, L. J. Wang, X. F. Wu

Almost all superluminous supernovae (SLSNe) whose peak magnitudes are \lesssim -21 mag can be explained by the 56Ni-powered model or magnetar-powered (highly magnetized pulsar) model or ejecta-circumstellar medium (CSM) interaction model. Recently, iPTF13ehe challenges these energy-source models, because the spectral analysis indicates that ~2.5 solar masses of 56Ni have been synthesised but are inadequate to power the peak bolometric emission of iPTF13ehe, while the rebrightening of the late-time light-curve (LC) and the H alpha emission lines indicate that the ejecta-CSM interaction must play a key role in powering the late-time LC. In this Letter, we show that the early LC of iPTF13ehe can be powered by a magnetar together with a large amount of 56Ni, while the late-time LC may be attributed to all three energy sources listed above. Therefore, iPTF13ehe is the first SLSN powered by triple energy sources. Furthermore, we propose that iPTF13ehe is a genuine core-collapse supernova (CCSN) rather than a pulsational pair-instability supernova (PPISN) candidate. Further studies on similar SLSNe in the future would eventually shed light on the nature of the explosion mechanisms and energy-mechanisms of these SLSNe.

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