Mysterious transients unmasked as the bright blue death throes of massive stars

Movies of the heavens, produced by modern synoptic imaging surveys, are
revolutionizing the field of cosmic explosions in astronomy. Recent discoveries
suggest entirely new pathways for the deaths of massive stars, and the
observational case for pair-instability supernovae has now been made. Other,
unexplained optical transient phenomena have engendered a wide range of models
as typified by the long duration and spectroscopically peculiar event SCP06F6
(theories range from a Texas sized asteroid impacting a white dwarf to the
eruption of a carbon rich star). Here we report three discoveries from the
newly commissioned Palomar Transient Factory (PTF) that resolve the mystery of
SCP06F6; we argue that these four events along with SN2005ap reveal the death
throes of the most massive stars — pulsational pair-instability outbursts. The
unprecedented ultra-violet peak luminosities (-23 mag) and longevity of these
events permit their discovery out to redshifts of 4 or more with existing
telescopes and may be exploited by future, large aperture facilities to study
the interstellar medium of primitive galaxies.