SN 2009kf : a UV bright type IIP supernova discovered with Pan-STARRS 1
  and GALEX
  We present photometric and spectroscopic observations of a luminous type IIP
Supernova 2009kf discovered by the Pan-STARRS 1 (PS1) survey and detected also
by GALEX. The SN shows a plateau in its optical and bolometric light curves,
lasting approximately 70 days in the rest frame, with absolute magnitude of M_V
= -18.4 mag. The P-Cygni profiles of hydrogen indicate expansion velocities of
9000km/s at 61 days after discovery which is extremely high for a type IIP SN.
SN 2009kf is also remarkably bright in the near-ultraviolet (NUV) and shows a
slow evolution 10-20 days after optical discovery. The NUV and optical
luminosity at these epochs can be modelled with a black-body with a hot
effective temperature (T ~16,000 K) and a large radius (R ~1x10^{15} cm). The
bright bolometric and NUV luminosity, the lightcurve peak and plateau duration,
the high velocities and temperatures suggest that 2009kf is a type IIP SN
powered by a larger than normal explosion energy. Recently discovered high-z
SNe (0.7 < z < 2.3) have been assumed to be IIn SNe, with the bright UV
luminosities due to the interaction of SN ejecta with a dense circumstellar
medium (CSM). UV bright SNe similar to SN 2009kf could also account for these
high-z events, and its absolute magnitude M_NUV = -21.5 +/- 0.5 mag suggests
such SNe could be discovered out to z ~2.5 in the PS1 survey.
