Millisecond Magnetars

Two classes of X-ray/$\gamma$-ray sources, the Soft Gamma Repeaters and Anomalous X-ray Pulsars have been identified with isolated, slowly spinning magnetars, neutron stars whose emission draws energy from their extremely strong magnetic field ($\sim 10^{15}-10^{16}$ G). Magnetars are believed to form millisecond spin period represent an important fraction whole population young stars. Newborn magnetars can convert very quickly rotational into electromagnetic and/or gravitational waves, by virtue fields fast spins. This chapter provides a brief summary astrophysical problems scenarios in which play key role: these include Ray Bursts, Supernovae, Gravitational Wave events Fast Radio Bursts.