Gamma-ray bursts (GRBs) are systems of unprecedented complexity across all
the electromagnetic spectrum, including the radio, optical, X-rays, gamma-rays
in the megaelectronvolt (MeV) and gigaelectronvolt (GeV) regime, as well as
ultrahigh-energy cosmic rays (UHECRs), each manifested in seven specific
physical processes with widely different characteristic evolution timescales
ranging from $10^{-14}$ s to $10^{7}$ s or longer. We here study the long GRB
180720B originating from a binary system composed of a massive carbon-oxygen
(CO) star of about $10 M_\odot$ and a companion neutron star (NS). The
gravitational collapse of the CO star gives rise to a spinning newborn NS
($\nu$NS), with an initial period of $P_0=1$ ms that powers the synchrotron
radiation in the radio, optical, and X-ray wavelengths. We here only
investigate the GRB 180720B afterglows and present a detailed treatment of its
origin based on the synchrotron radiation released by the interaction of the
$\nu$NS and the SN ejecta. We show that in parallel to the X-ray afterglow, the
spinning $\nu$NS also powers the optical and radio afterglows and allows us to
infer the $\nu$NS and ejecta parameters that fit the observational data.
