A lanthanide-rich kilonova in the aftermath of a long gamma-ray burst

Yu Han Yang, Eleonora Troja, Brendan O’Connor, Chris L. Fryer, Myungshin Im, Joe Durbak, Gregory S.H. Paek, Roberto Ricci, Clécio R. Bom, James H. Gillanders, Alberto J. Castro-Tirado, Zong Kai Peng, Simone Dichiara, Geoffrey Ryan, Hendrik van Eerten, Zi Gao Dai, Seo Won Chang, Hyeonho Choi, Kishalay De, Youdong HuCharles D. Kilpatrick, Alexander Kutyrev, Mankeun Jeong, Chung Uk Lee, Martin Makler, Felipe Navarete, Ignacio Pérez-García

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Observationally, kilonovae are astrophysical transients powered by the radioactive decay of nuclei heavier than iron, thought to be synthesized in the merger of two compact objects1–4. Over the first few days, the kilonova evolution is dominated by a large number of radioactive isotopes contributing to the heating rate2,5. On timescales of weeks to months, its behaviour is predicted to differ depending on the ejecta composition and the merger remnant6–8. Previous work has shown that the kilonova associated with gamma-ray burst 230307A is similar to kilonova AT2017gfo (ref. 9), and mid-infrared spectra revealed an emission line at 2.15 micrometres that was attributed to tellurium. Here we report a multi-wavelength analysis, including publicly available James Webb Space Telescope data9 and our own Hubble Space Telescope data, for the same gamma-ray burst. We model its evolution up to two months after the burst and show that, at these late times, the recession of the photospheric radius and the rapidly decaying bolometric luminosity (Lbol ∝ t−2.7±0.4, where t is time) support the recombination of lanthanide-rich ejecta as they cool.

Original languageEnglish (US)
Pages (from-to)742-745
Number of pages4
JournalNature
Volume626
Issue number8000
DOIs
StatePublished - Feb 22 2024

All Science Journal Classification (ASJC) codes

  • General

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