The most distant $\gamma$-ray flare to date: a multiwavelength campaign on the $z=4.715$ blazar GB6 B1428+4217

Andrea Gokus, Manel Errando, Ivan Agudo +12

In November 2023, the Fermi Large Area Telescope detected a $\gamma$-ray flare from the high-redshift blazar GB6 B1428+4217 ($z=4.715$). We initiated a multi-wavelength follow-up campai…