During a core-collapse supernova ( SN ) , axionlike particles ( ALPs ) could be produced through the Primakoff process and subsequently convert into \gamma rays in the magnetic field of the Milky Way .
We do not find evidence for such a \gamma -ray burst in observations of extragalactic SNe with the Fermi Large Area Telescope ( LAT ) .
The SN explosion times are estimated from optical light curves and we find a probability of about \sim 90 \% that the LAT observed at least one SN at the time of the core collapse .
Under the assumption that at least one SN was contained within the LAT field of view , we exclude photon-ALP couplings \gtrsim 2.6 \times 10 ^ { -12 } \mathrm { GeV } ^ { -1 } for ALP masses m _ { a } \lesssim 3 \times 10 ^ { -10 } eV , improving previous limits from SN1987A by a factor of 2 .