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GCN Circular 36495

LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits
2024-05-16T11:33:35Z (12 days ago)
GRID Student Team at Tsinghua University <>
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Chenyu Wang, Zirui Yang and Longhao Li report on behalf of the GRID Collaboration:

We have carried out a search for GRB candidates in GRID data in a 50 sec window around the trigger time of the event S240422ed (UTC 2024-04-22 21:35:13, GraceDB event).

We do not find any evidence for any GRB transient in this window, in the GRID energy range of 10-1000 keV. At the time of the merger, GRID-04's nominal pointing is RA,DEC = 353.93, -48.06, which is ~94 deg away from the maximum probability location.

We set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2):

Timescale  Upper limit
0.128 s:       6.2
1.024 s:       2.7
8.192 s:       1.3

GRID is a student-led project to monitor the transient gamma-ray sky with multiple detectors onboard different nanosatellites in the era of multi-messenger astronomy. For more information about GRID, please refer to the following references: and

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