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 language | English (US) |
|---|---|
| Pages (from-to) | 742-745 |
| Number of pages | 4 |
| Journal | Nature |
| Volume | 626 |
| Issue number | 8000 |
| DOIs | |
| State | Published - Feb 22 2024 |
Funding
This work was supported by the European Research Council through the Consolidator grant BHianca (grant agreement ID 101002761) and, in part, by the National Science Foundation (under award number 2108950). This work was in part carried out at the Aspen Center for Physics, which is supported by National Science Foundation grant PHY-2210452. The development of afterglow models used in this work was partially supported by the European Union Horizon 2020 programme under the AHEAD2020 project (grant agreement number 871158). B.O. acknowledges useful discussions with J. Pierel and O. Fox regarding JWST analysis. M.I., G.S.H.P., S.-W.C., H.C. and M.J. acknowledge support from the National Research Foundation of Korea (NRF) grants, no. 2020R1A2C3011091 and no. 2021M3F7A1084525, funded by the Korea government (MSIT). C.R.B. acknowledges the financial support from CNPq (316072/2021-4) and from FAPERJ (grants 201.456/2022 and 210.330/2022) and the FINEP contract 01.22.0505.00 (ref.1891/22). C.R.B. made use of HPC Sci-Mind servers machines developed and supported by the CBPF AI LAB team. This research has made use of the KMTNet system operated by the Korea Astronomy and Space Science Institute (KASI) at three host sites of CTIO in Chile, SAAO in South Africa, and SSO in Australia. Data transfer from the host site to KASI and SNU was supported by the Korea Research Environment Open NETwork (KREONET). A.J.C.-T. acknowledges funding of the Spanish Ministry project PID2020-118491GB-I00/AEI/10.13039/501100011033. The observations included data obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Minist\u00E9rio da Ci\u00EAncia, Tecnologia e Inova\u00E7\u00F5es (MCTI/LNA) do Brasil, the US National Science Foundation\u2019s NOIRLab, the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). The national facility capability for SkyMapper has been funded through ARC LIEF grant LE130100104 from the Australian Research Council, awarded to the University of Sydney, the Australian National University, Swinburne University of Technology, the University of Queensland, the University of Western Australia, the University of Melbourne, Curtin University of Technology, Monash University and the Australian Astronomical Observatory. SkyMapper is owned and operated by The Australian National University\u2019s Research School of Astronomy and Astrophysics. The survey data were processed and provided by the SkyMapper Team at ANU. The SkyMapper node of the All-Sky Virtual Observatory (ASVO) is hosted at the National Computational Infrastructure (NCI). Development and support of the SkyMapper node of the ASVO has been funded in part by Astronomy Australia Limited (AAL) and the Australian Government through the Commonwealth\u2019s Education Investment Fund (EIF) and National Collaborative Research Infrastructure Strategy (NCRIS), particularly the National eResearch Collaboration Tools and Resources (NeCTAR) and the Australian National Data Service Projects (ANDS).
ASJC Scopus subject areas
- General