The Double-Peaked SN2013ge: a Type Ib/c SN with an Asymmetric Mass
  Ejection or an Extended Progenitor Envelope
  We present extensive observations of the Type Ib/c SN2013ge from -13 to +457
days, including spectra and Swift UV-optical photometry beginning 2-4 days
post-explosion. This data set makes SN2013ge one of the best observed normal
Type Ib/c SN at early times---when the light curve is particularly sensitive to
the progenitor configuration and mixing of radioactive elements---and reveals
two distinct light curve components in the UV bands. The first component rises
over 4-5 days and is visible for the first week post-explosion. Spectra of the
first component have blue continua and show a plethora of high velocity
(~15,000 km/s) but narrow (~3500 km/s) features, indicating that the
line-forming region is restricted. The explosion parameters estimated for the
bulk explosion are standard for Type Ib/c SN, and there is evidence for weak He
features at early times. In addition, SN2013ge exploded in a low metallicity
environment and we have obtained some of the deepest radio and X-ray limits for
a Type Ib/c SN to date, which constrain the progenitor mass-loss rate. We are
left with two distinct progenitor scenarios for SN2013ge, depending on our
interpretation of the early emission. If the first component is cooling
envelope emission, then the progenitor of SN2013ge either possessed a low-mass
extended envelope or ejected a portion of its envelope in the final <1 year
before core-collapse. Alternatively, if the first component is due to outwardly
mixed Ni-56, then our observations are consistent with the asymmetric ejection
of a distinct clump of nickel-rich material at high velocities. Current models
for the collision of a SN shock with a binary companion cannot reproduce both
the timescale and luminosity of the early emission in SN2013ge. Finally, the
spectra of the first component of SN2013ge are similar to those of the
rapidly-declining SN2002bj.
