GRB 221009A: observations 8 hours later with HAWC and Fermi-LAT

The gamma-ray burst GRB221009A has been the brightest GRB observed so far. It was even observed >10 TeV and its afterglow has been studied over a large range of the electromagnetic spectrum. After 8 hours of the initial trigger, the position of the burst started to transit the HAWC observatory. No significant detection was found in searches of timescales of hundreds of seconds to hours. However, 1.3 hours into the transit, the Fermi-LAT telescope detected a 400 GeV photon 0.1deg away from the GRB position, with a probability of being a random coincidence of 4σ. Using both HAWC and Fermi data we searched for a possible late-time flare or rebrighting of the GRB, as well as performed a spectral fit of the afterglow over the energy range of ~100 MeV to 10 TeV. We will present the results of these analyses during this talk.