Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - The case for a minute-long merger-driven gamma-ray burst from fast-cooling synchrotron emission
AU - Gompertz, Benjamin P.
AU - Ravasio, Maria Edvige
AU - Nicholl, Matt
AU - Levan, Andrew J.
AU - Metzger, Brian D.
AU - Oates, Samantha R.
AU - Lamb, Gavin P.
AU - Fong, Wen-fai
AU - Malesani, Daniele B.
AU - Rastinejad, Jillian C.
AU - Tanvir, Nial R.
AU - Evans, Philip A.
AU - Jonker, Peter G.
AU - Page, Kim L.
AU - Pe’er, Asaf
PY - 2023/1/31
Y1 - 2023/1/31
N2 - For decades, gamma-ray bursts (GRBs) have been broadly divided into long- and short-duration bursts, lasting more or less than 2 s, respectively. However, this dichotomy does not perfectly map to the two progenitor channels that are known to produce GRBs: mergers of compact objects (merger GRBs) or the collapse of massive stars (collapsar GRBs). In particular, the merger GRB population may also include bursts with a short, hard <2 s spike and subsequent longer, softer extended emission. The recent discovery of a kilonova—the radioactive glow of heavy elements made in neutron star mergers—in the 50-s-duration GRB 211211A further demonstrates that mergers can drive long, complex GRBs that mimic the collapsar population. Here we present a detailed temporal and spectral analysis of the high-energy emission of GRB 211211A. We demonstrate that the emission has a purely synchrotron origin, with both the peak and cooling frequencies moving through the γ-ray band down to X-rays, and that the rapidly evolving spectrum drives the extended emission signature at late times. The identification of such spectral evolution in a merger GRB opens avenues to diagnostics of the progenitor type.
AB - For decades, gamma-ray bursts (GRBs) have been broadly divided into long- and short-duration bursts, lasting more or less than 2 s, respectively. However, this dichotomy does not perfectly map to the two progenitor channels that are known to produce GRBs: mergers of compact objects (merger GRBs) or the collapse of massive stars (collapsar GRBs). In particular, the merger GRB population may also include bursts with a short, hard <2 s spike and subsequent longer, softer extended emission. The recent discovery of a kilonova—the radioactive glow of heavy elements made in neutron star mergers—in the 50-s-duration GRB 211211A further demonstrates that mergers can drive long, complex GRBs that mimic the collapsar population. Here we present a detailed temporal and spectral analysis of the high-energy emission of GRB 211211A. We demonstrate that the emission has a purely synchrotron origin, with both the peak and cooling frequencies moving through the γ-ray band down to X-rays, and that the rapidly evolving spectrum drives the extended emission signature at late times. The identification of such spectral evolution in a merger GRB opens avenues to diagnostics of the progenitor type.
U2 - 10.1038/s41550-022-01819-4
DO - 10.1038/s41550-022-01819-4
M3 - Journal article
VL - 7
SP - 67
EP - 79
JO - Nature Astronomy
JF - Nature Astronomy
SN - 2397-3366
ER -