Carnegie Supernova Project-II: Using Near-infrared Spectroscopy to Determine the Location of the Outer 56Ni in Type Ia Supernovae Academic Article uri icon


  • Abstract We present the H-band wavelength region of 37 postmaximum light near-infrared spectra of three normal, nine transitional, and four subluminous typeIa supernovae (SNe Ia), extending from +5days to +20days relative to the epoch of B-band maximum. We introduce a new observable, the blue-edge velocity, v edge, of the prominent Fe/Co/Ni-peak H-band emission feature, which is quantitatively measured. The v edge parameter is found to decrease over subtype ranging from around 14,000kms1 for normal SNe Ia, to 10,000kms1 for transitional SNeIa, down to 5000kms1 for the subluminous SNeIa. Furthermore, inspection of the +103 days spectra indicates that v edge is correlated with the color-stretch parameter, s BV , and hence with peak luminosity. These results follow the previous findings that brighter SNeIa tend to have 56Ni located at higher velocities as compared to subluminous objects. As v edge is a model-independent parameter, we propose it can be used in combination with traditional observational diagnostics to provide a new avenue to robustly distinguish between leading SNeIa explosion models.

published proceedings


altmetric score

  • 10.25

author list (cited authors)

  • Ashall, C., Hsiao, E. Y., Hoeflich, P., Stritzinger, M., Phillips, M. M., Morrell, N., ... Taddia, F.

citation count

  • 27

publication date

  • April 2019