Constraining the long-lived supramassive neutron stars by magnetar boosted kilonovae

Hao Wang, Paz Beniamini, Dimitrios Giannios

Research output: Contribution to journalArticlepeer-review


Kilonovae are optical transients following the merger of neutron star binaries, which are powered by the r-process heating of merger ejecta. However, if a merger remnant is a long-lived supramassive neutron star supported by its uniform rotation, it will inject energy into the ejecta through spin-down power. The energy injection can boost the peak luminosity of a kilonova by many orders of magnitudes, thus significantly increasing the detectable volume. Therefore, even if such events are only a small fraction of the kilonova population, they could dominate the detection rates. However, after many years of optical sky surveys, no such event has been confirmed. In this work, we build a boosted kilonova model with rich physical details, including the description of the evolution and stability of a proto neutron star, and the energy absorption through X-ray photoionization. We simulate the observation prospects and find the only way to match the absence of detection is to limit the energy injection by the newly born magnetar to only a small fraction of the neutron star rotational energy, thus they should collapse soon after the merger. Our result indicates that most supramassive neutron stars resulting from binary neutron star mergers are short lived and they are likely to be rare in the Universe.

Original languageEnglish
Pages (from-to)5166-5182
Number of pages17
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
StatePublished - 1 Jan 2024

Bibliographical note

Publisher Copyright:
© 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.


  • equation of state
  • neutron star mergers
  • radiation mechanisms:general
  • stars: magnetars
  • stars: neutron


Dive into the research topics of 'Constraining the long-lived supramassive neutron stars by magnetar boosted kilonovae'. Together they form a unique fingerprint.

Cite this