期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 497, 期 1, 页码 246-262出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/staa1822
关键词
line: identification; radiative transfer; binaries: close; stars: neutron; supernovae: individual: AT2018kzr; white dwarfs
资金
- STFC [ST/P000312/1]
- W. M. Keck Foundation
- Google Summer ofCode initiative
- ESA's Summer ofCode in Space program
- ESO program -ePESSTO [199.D-0143]
- STFC [ST/P000312/1] Funding Source: UKRI
We present detailed spectroscopic analysis of the extraordinarily fast-evolving transient AT2018kzr. The transient's observed light curve showed a rapid decline rate, comparable to the kilonova AT2017gfo. We calculate a self-consistent sequence of radiative transfer models (using TARDIS) and determine that the ejecta material is dominated by intermediate-mass elements (O, Mg, and Si), with a photospheric velocity of similar to 12 000-14 500 km s(-1). The early spectra have the unusual combination of being blue but dominated by strong Fe II and Fe III absorption features. We show that this combination is only possible with a high Fe content (3.5 per cent). This implies a high Fe/(Ni+Co) ratio. Given the short time from the transient's proposed explosion epoch, the Fe cannot be Fe-56 resulting from the decay of radioactive Ni-56 synthesized in the explosion. Instead, we propose that this is stable Fe-54, and that the transient is unusually rich in this isotope. We further identify an additional, high-velocity component of ejecta material at similar to 20 000-26 000 km s(-1), which is mildly asymmetric and detectable through the Ca II near-infrared triplet. We discuss our findings with reference to a range of plausible progenitor systems and compare with published theoretical work. We conclude that AT2018kzr is most likely the result of a merger between an ONe white dwarf and a neutron star or black hole. As such, it would be the second plausible candidate with a good spectral sequence for the electromagnetic counterpart of a compact binary merger, after AT2017gfo.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据