A long-duration gamma-ray burst with a peculiar origin

Article

关键词: CENTRAL ENGINE;    SPECTRA;   

DOI  :  10.1038/s41586-022-05403-8

来源: SCIE

【 摘 要 】

It is generally believed that long-duration gamma-ray bursts (GRBs) are associated with massive star core collapse(1), whereas short-duration GRBs are associated with mergers of compact star binaries(2). However, growing observations(3-6) have suggested that oddball GRBs do exist, and several criteria (prompt emission properties, supernova/kilonova associations and host galaxy properties) rather than burst duration only are needed to classify GRBs physically(7). A previously reported long-duration burst, GRB 060614 (ref. (3)), could be viewed as a short GRB with extended emission if it were observed at a larger distance(8) and was associated with a kilonova-like feature(9). As a result, it belongs to the type I (compact star merger) GRB category and is probably of binary neutron star (NS) merger origin. Here we report a peculiar long-duration burst, GRB 211211A, whose prompt emission properties in many aspects differ from all known type I GRBs, yet its multiband observations suggest a non-massive-star origin. In particular, substantial excess emission in both optical and near-infrared wavelengths has been discovered (see also ref. (10)), which resembles kilonova emission, as observed in some type I GRBs. These observations point towards a new progenitor type of GRBs. A scenario invoking a white dwarf (WD)-NS merger with a post-merger magnetar engine provides a self-consistent interpretation for all the observations, including prompt gamma rays, early X-ray afterglow, as well as the engine-fed(11,12) kilonova emission.

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