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Published March 2016 | Submitted + Published
Journal Article Open

Metallicity from Type II supernovae from the (i)PTF

Abstract

Type IIP supernovae (SNe IIP) have recently been proposed as metallicity (Z) probes. The spectral models of Dessart et al. (2014, MNRAS, 440, 1856) showed that the pseudo-equivalent width of Fe II λ5018 (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 < 0.4 Z⊙. 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⊙ up to Z ≈ 2 Z⊙. We also independently investigated the Z of the hosts by using their absolute magnitudes and colors and, in a few cases, using strong-line diagnostics from spectra. We searched for possible correlations between SN observables, such as their peak magnitudes and the Z inferred from pEW_(5018). We found 11 events with pEW_(5018) that were small enough to indicate Z ≈ 0.1 Z⊙. The trend of pEW_(5018) with Z matches the Z estimates obtained from the host-galaxy photometry, although the significance of the correlation is weak. We also found that SNe with brighter peak magnitudes have smaller pEW_(5018) and occur at lower Z.

Additional Information

© 2016 ESO. Received 16 December 2015; Accepted 7 February 2016. We gratefully acknowledge the support from the Knut and Alice Wallenberg Foundation. The Oskar Klein Centre is funded by the Swedish Research Council. A.G.-Y. is supported by the EU/FP7 via ERC grant No. 307260, the Quantum Universe I-Core program by the Israeli Committee for Planning and Budgeting and the ISF; by Minerva and ISF grants; by the Weizmann-UK "making connections" program; and by Kimmel and ARCHES awards. A.V.F.'s research is supported by the Christopher R. Redlich Fund, the TABASGO Foundation, and NSF grant AST-1211916. We are grateful to the staffs at the many observatories where data for this study were collected (Palomar, Lick, Keck, etc.). We thank R. Foley, J. Bloom, Green, N. Cucchiara, A. Horesh, K. I. Clubb, M. T. Kandrashoff, K. Maguire, A. De Cia, S. Tang, B. Zackay, B. Sesar, A. Waszczak, I. Shivvers, who helped with some of the observations and data reduction. Research at Lick Observatory is partially supported by a generous gift from Google. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA; the observatory was made possible by the generous financial support of the W. M. Keck Foundation. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231. J.M.S. is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1302771. D.X. acknowledges the support of the One-Hundred-Talent Program from the National Astronomical Observatories, Chinese Academy of Sciences. This work is partly based on the Bachelor thesis by P. Moquist.

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Published - aa27983-15.pdf

Submitted - 1602.01433v2.pdf

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Additional details

Created:
August 20, 2023
Modified:
October 18, 2023