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Abstract GW230529 is the first compact binary coalescence detected by the LIGO–Virgo–KAGRA collaboration with at least one component mass confidently in the lower mass gap, corresponding to the range 3–5M⊙. If interpreted as a neutron star–black hole merger, this event has the most symmetric mass ratio detected so far and therefore has a relatively high probability of producing electromagnetic (EM) emission. However, no EM counterpart has been reported. At the merger timet0, Swift-BAT and Fermi-GBM together covered 100% of the sky. Performing a targeted search in a time window [t0− 20 s,t0+ 20 s], we report no detection by the Swift-BAT and Fermi-GBM instruments. Combining the position-dependentγ-ray flux upper limits and the gravitational-wave posterior distribution of luminosity distance, sky localization, and inclination angle of the binary, we derive constraints on the characteristic luminosity and structure of the jet possibly launched during the merger. Assuming atop-hatjet structure, we exclude at 90% credibility the presence of a jet that has at the same time an on-axis isotropic luminosity ≳1048erg s−1in the bolometric band 1 keV–10 MeV and a jet opening angle ≳15°. Similar constraints are derived by testing other assumptions about the jet structure profile. Excluding GRB 170817A, the luminosity upper limits derived here are below the luminosity of any GRB observed so far.
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This content will become publicly available on March 7, 2026
Limits on the Low-energy Electron Antineutrino Flux from the Brightest Gamma-Ray Burst of All Time
Abstract The electron antineutrino flux limits are presented for the brightest gamma-ray burst (GRB) of all time, GRB221009A, over a range of 1.8–200 MeV using the Kamioka Liquid Scintillator Antineutrino Detector. Using multiple time windows ranging from minutes to days surrounding the event to search for electron antineutrinos coincident with the GRB, we set an upper limit on the flux under the assumption of several power-law neutrino source spectra, with power-law indices ranging from 1.5 to 3 in steps of 0.5. No excess was observed in any time windows ranging from seconds to days around the event trigger timeT0. For a power-law index of 2 and a time window ofT0 ± 500 s, a flux upper limit of 2.34 × 109cm−2was calculated. The limits are compared to the results presented by IceCube.
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- Award ID(s):
- 2110720
- PAR ID:
- 10636065
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- AAS Publishing
- Date Published:
- Journal Name:
- Astrophysical journal
- Volume:
- 981
- Issue:
- 2
- ISSN:
- 1538-4357
- Page Range / eLocation ID:
- 192
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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