2013ApJ...772L..17T

We present a set of photometric and spectroscopic observations of a bright Type Ib supernova SN 2012au from -6 days until ∼ + 150 days after maximum. The shape of its early R-band light curve is similar to that of an average Type Ib/c supernova. The peak absolute magnitude is M_R= -18.7 ±0.2 mag, which suggests that this supernova belongs to a very luminous group among Type Ib supernovae. The line velocity of He I λ5876 is about 15,000 km/s around maximum, which is much faster than that in a typical Type Ib supernova. From the quasi-bolometric peak luminosity of (6.7 ±1.3)x10⁴² erg/s, we estimate the ⁵⁶Ni mass produced during the explosion as ∼0.30 M_☉. We also give a rough constraint to the ejecta mass 5-7 M_☉ and the kinetic energy (7-18)x10⁵¹ erg. We find a weak correlation between the peak absolute magnitude and He I velocity among Type Ib SNe. The similarities to SN 1998bw in the density structure inferred from the light-curve model as well as the large peak bolometric luminosity suggest that SN 2012au had properties similar to energetic Type Ic supernovae.