Selecting superluminous supernovae in faint galaxies from the first year
  of the Pan-STARRS1 Medium Deep Survey
  The Pan-STARRS1 (PS1) survey has obtained imaging in 5 bands (grizy_P1) over
10 Medium Deep Survey (MDS) fields covering a total of 70 square degrees. This
paper describes the search for apparently hostless supernovae (SNe) within the
first year of PS1 MDS data with an aim of discovering new superluminous
supernovae (SLSNe). A total of 249 hostless transients were discovered down to
a limiting magnitude of M_AB ~ 23.5, of which 76 were classified as Type Ia
SNe. There were 57 SNe with complete light curves that are likely core-collapse
SNe (CCSNe) or SLSNe and 12 of these have had spectra taken. Of these 12
hostless, non-Type Ia SNe, 7 were SLSNe of Type Ic at redshifts between
0.5-1.4. This illustrates that the discovery rate of Type Ic SLSNe can be
maximised by concentrating on hostless transients and removing normal SNe Ia.
We present data for two new possible SLSNe; PS1-10pm (z = 1.206) and PS1-10ahf
(z = 1.1), and estimate the rate of SLSNe-Ic to be between 3^{+3}_{-2} *
10^{-5} and 8^{+2}_{-1} * 10^{-5} of the CCSNe rate within 0.3 <= z <= 1.4 by
applying a Monte-Carlo technique. The rate of slowly evolving, SN2007bi-like
explosions is estimated as a factor of 10 lower than this range.
