Author: V. Stanishev (Stockholm University) and the European Supernova
Collaboration
We present an extensive set of optical observations of the peculiar Type Ia
SN 2005hk during the first three months after the explosion. We show that
the evolution of SN 2005hk closely follows that of the peculiar SN
2002cx. SN 2005hk is more luminous than SN 2002cx, while still
under-luminous compared to normal Type Ia supernovae. The spectrum at 9
days before maximum is dominated by conspicuous Fe III and Ni III
lines, and the Si II 6355 line is also clearly visible. The near-maximum
spectra show lines of Si II, S II, Fe II, Fe III, as well as other
intermediate mass and iron group elements. The velocities of the lines in
all these spectra are rather low (~6000 km/s). We also present
near-infrared spectra of SN 2005hk around maximum light and late-time
optical and near-infrared photometry.