Optical observations of the broad-lined type Ic supernova SN 2012ap

The optical observations of the type Ic supernova (SN Ic) SN 2012ap in NGC 1729 are presented. A comparison with other SNe Ic indicates that SN 2012ap is highly reddened (with E (B -V)(host)similar to 0.8 mag) and may represent one of the most luminous SNe Ic ever observed, with an absolute V-band peak magnitude of similar to -19.3 +/- 0.5 mag after extinction correction. The near-maximum-light spectrum shows wide spectral features that are typical of broad-lined SNe Ic. One interesting feature in the spectrum is the appearance of some narrow absorption features that can be attributed to the diffuse interstellar bands, consistent with the large reddening inferred from the photometric method. Based on the light curves and the spectral data, we estimate that SN 2012ap produced a Ni-56 mass of similar to 0.3 +/- 0.1 M-circle dot in the explosion, with an ejecta mass of 2.4(-0.7)(+0.7) M-circle dot and a kinetic energy of E-K = 1.1(-0.4)(+0.4) x 10(52) erg. The properties of its progenitor are also briefly discussed.