Significant luminosity differences of two twin Type Ia supernovae
Author
Foley, Ryan JHoffmann, Samantha L
Macri, Lucas M
Riess, Adam G
Brown, Peter J
Filippenko, Alexei V
Graham, Melissa L
Milne, Peter A
Affiliation
Univ Arizona, Steward ObservIssue Date
2019-11-28Keywords
supernovae: generalsupernovae: individual: SN 2011by
SN 2011fe
galaxies: individual: M101, NGC 3972
Metadata
Show full item recordPublisher
OXFORD UNIV PRESSCitation
Ryan J Foley, Samantha L Hoffmann, Lucas M Macri, Adam G Riess, Peter J Brown, Alexei V Filippenko, Melissa L Graham, Peter A Milne, Significant luminosity differences of two twin Type Ia supernovae, Monthly Notices of the Royal Astronomical Society, Volume 491, Issue 4, February 2020, Pages 5991–5999, https://doi.org/10.1093/mnras/stz3324Rights
Copyright © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
The Type Ia supernovae (SNe Ia) 2011by, hosted in NGC 3972, and 2011fe, hosted in M101, are optical 'twins,' having almost identical optical light-curve shapes, colours, and near-maximum-brightness spectra. However, SN 2011fe had significantly more ultraviolet (UV; 1600 < lambda < 2500 angstrom) flux than SN 2011by before and at peak luminosity. Several theoretical models predict that SNe Ia with higher progenitor metallicity should (1) have additional UV opacity and thus lower UV flux; (2) have an essentially unchanged optical spectral-energy distribution; (3) have a similar optical light-curve shape; and (4) because of the excess neutrons, produce more stable Fe-group elements at the expense of radioactive Ni-56 and thus have a lower peak luminosity. Following these predictions, Foley and Kirshner suggested that the difference in UV flux between SNe 2011by and 2011fe was the result of their progenitors having significantly different metallicities. They also measured a large, but insignificant, difference between the peak absolute magnitudes of the SNe (Delta M-V,M- peak = 0.60 +/- 0.36 mag), with SN 2011fe being more luminous. We present a new Cepheid-based distance to NGC 3972, substantially improving the precision of the distance measurement for SN 2011by. With these new data, we determine that the SNe have significantly different peak luminosities (Delta M-V,M- peak = 0.335 +/- 0.069 mag). Consequently, SN 2011fe produced 38 per cent more Ni-56 than SN 2011by, consistent with predictions for progenitor metallicity differences for these SNe, although alternative models may also explain this difference. We discuss how progenitor metallicity differences can contribute to the intrinsic scatter for light-curve-shape-corrected SN luminosities, the use of 'twin' SNe for measuring distances, and implications for using SNe Ia for constraining cosmological parameters.ISSN
0035-8711Version
Final published versionae974a485f413a2113503eed53cd6c53
10.1093/mnras/stz3324