A Spectroscopic Analysis of the Energetic Type Ic Hypernova SN 1997ef

Citations Over TimeTop 10% of 2000 papers

Abstract

The properties of the bright and energetic Type Ic SN 1997ef are investigated using a Monte Carlo spectrum synthesis code. Analysis of the earliest spectra is used to determine the time of outburst. The changing features of the spectrum and the light curve are used to probe the ejecta and to determine their composition, verifying the results of explosion calculations. Since synthetic spectra computed using our best explosion model CO100 are only moderately good reproductions of the observations, the inverse approach is adopted, and a density structure is derived by demanding that it gives the best possible fit to the observed spectrum at every epoch analysed. It is found that the density structure of model CO100 is adequate at intermediate velocities (5000--25000 km/s), but that a slower density decline ($\rho \propto r^{-4}$) is required to obtain the extensive line blending at high velocities (25000--50000 km/s). The `best fit' density distribution results in somewhat different parameters for the SN, namely an ejecta mass of 9.6$M_\odot$ and an explosion kinetic energy of 1.75 x 10^{52} erg. The modified density structure is used to compute a synthetic light curve, which is found to agree very well with the observed bolometric light curve around maximum. The amount of radioactive $^{56}$Ni produced by the SN is confirmed at 0.13$M_\odot$. In the context of an axisymmetric explosion, a somewhat smaller kinetic energy than that of SN 1998bw may have resulted from the non alignment of the symmetry axis of the SN and the line of sight. This might also explain the lack of evidence for a Gamma Ray Burst correlated with SN 1997ef.

Related Papers

• → Three-dimensional Hydrodynamic Simulations of Supernova Ejecta with a Central Energy Source(2019)26 cited
• → X-ray illumination of the ejecta of supernova 1987A(2011)81 cited
• → On the Geometry of the High‐Velocity Ejecta of the Peculiar Type Ia Supernova 2000cx(2004)39 cited
• → Explaining the Early Excess Emission of the Type Ia Supernova 2018oh by the Interaction of the Ejecta with Disk-originated Matter(2019)29 cited
• → Spectral sequences of Type Ia supernovae. I. Connecting normal and sub-luminous SN Ia and the presence of unburned carbon(2017)