New physics through a multimessenger lens: searching for axion-like particles from transient astrophysical events

Axion-like particles (ALPs) are a well-motivated candidate for constituting a significant fraction of dark matter. They are produced in high-energy environments, such as core-collapse supernovae (CCSNe) or binary neutron star (BNS) mergers. They could undergo conversion into gamma-rays in the presence of an external magnetic field, with a characteristic spectrum peaking in the MeV energy range. As CCSNe and BNS mergers are progenitors to gamma-ray bursts (GRBs), studying the gamma-ray spectra of GRBs can be used as a probe into the physical properties of ALPs. Here, we present the results from ALP searches using the Fermi Large Area Telescope (LAT) observations of long-duration GRBs using both the standard, as well as LAT's Low Energy (LLE) technique. We use the LLE technique to report the Fermi sensitivity limits to detect ALPs to distances up to ~10 Mpc, comparable to the standard LAT analysis results. We also share the preliminary results on the ALP-photon coupling using the LAT-detected GRBs. Furthermore, we offer an overview and motivation for utilizing the already-in-place multimessenger infrastructure for future ALP searches from BNS mergers, as well as introduce new venues exploring new physics guided by the current and future multimessenger efforts which will allow us to establish competitive upper limits on the ALP parameter space.