Metallicity from Type II SN from (i)PTF

The spectral models of Dessart et al. (2014MNRAS.440.1856D) showed that the pseudo-equivalent width of FeII {lambda}5018 (pEW_5018_) during the plateau phase depends on the primordial Z, but there was a paucity of SNe IIP exhibiting pEW_5018_ that were compatible with Z<0.4Z_{sun}_. This lack might be due to some physical property of the SN II population or to the fact that those SNe have been discovered in luminous, metal-rich targeted galaxies.

Here we use SN II observations from the untargeted (intermediate) Palomar Transient Factory [(i)PTF] survey, aiming to investigate the pEW_5018_ distribution of this SN population and, in particular, to look for the presence of SNe II at lower Z. We perform pEW_5018_ measurements on the spectra of a sample of 39 (i)PTF SNe II, selected to have well-constrained explosion epochs and light-curve properties. Based on the comparison with the pEW_5018_ spectral models, we subgrouped our SNe into four Z bins from Z=~0.1 Z_{sun}_ up to Z=~2 Z_{sun}_.