  The purpose of this study is to investigate radiation from asymptotic zero
acceleration motion where a horizon is formed and subsequently detected by an
outside witness. A perfectly reflecting moving mirror is used to model such a
system and compute the energy and spectrum. The trajectory is asymptotically
inertial (zero proper acceleration)-ensuring negative energy flux (NEF), yet
approaches light-speed with a null ray horizon at a finite advanced time. We
compute the spectrum and energy analytically.
