SN 2021pfs: A Type Ia Supernova Likely Affected by Progenitor Metallicity, as Revealed by Comparison with Its Twin Counterpart
Abstract
We present extensive photometric and spectroscopic observations of the normal type Ia supernovae (SNe Ia) 2021pfs, which occurred in the Seyfert 2 galaxy NGC 5427 at a redshift 0.009. SN 2021pfs reached an absolute \textit{B}-band peak magnitude of Mmax(B)=-19.28 ± 0.40 mag. The mag and a post-peak decline rate of Δm15(B)=1.13 ± 0.06 mag. The observed properties of this nearby SN Ia closely resemble those of SN 2011fe, including the main optical spectroscopic features and photometric evolution. Despite their similar decline rates, SN 2021pfs rose more rapidly in the U band but more slowly in the r and i bands compared to SN 2011fe in very early phases. This photometric difference, particularly at short wavelengths, can introduce a systematic uncertainty of up to ∼12% in distance estimates. Analysis of the host galaxy's local and global environment shows an environment consistent with producing a higher-metallicity progenitor for SN 2021pfs than that of SN 2011fe.This higher progenitor metallicity may explain the observed photometric discrepancy and the resulting distance between SN 2021pfs and SN 2011fe, though a larger sample of such "twin" SNe Ia is needed to confirm this trend and assess its impact on cosmological measurements.
Versions
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BibTeX
@misc{iskandar20262021pfs,
title = {{SN 2021pfs: A Type Ia Supernova Likely Affected by Progenitor Metallicity, as Revealed by Comparison with Its Twin Counterpart}},
author = {Abdusamatjan Iskandar and Xiaofeng Wang and Ali Esamdin and Wenxiong Li and Xiangyun Zeng and Ruifeng Huang and Hu Maokai and Guoliang Lu and D. Andrew Howell and Curtis McCully and Samuel Wyatt and Daichi Hiramatsu and Estefania Padilla Gonzalez and Craig Pellegrino and Megan Newsome and Lluis Galbany and David J. Sand and Nathan Smith and Huei Sears},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2608.19929},
eprint = {2608.19929},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.19929},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - SN 2021pfs: A Type Ia Supernova Likely Affected by Progenitor Metallicity, as Revealed by Comparison with Its Twin Counterpart
AU - Abdusamatjan Iskandar
AU - Xiaofeng Wang
AU - Ali Esamdin
AU - Wenxiong Li
AU - Xiangyun Zeng
AU - Ruifeng Huang
AU - Hu Maokai
AU - Guoliang Lu
AU - D. Andrew Howell
AU - Curtis McCully
AU - Samuel Wyatt
AU - Daichi Hiramatsu
AU - Estefania Padilla Gonzalez
AU - Craig Pellegrino
AU - Megan Newsome
AU - Lluis Galbany
AU - David J. Sand
AU - Nathan Smith
AU - Huei Sears
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2608.19929
UR - https://arxiv.org/abs/2608.19929
AB - We present extensive photometric and spectroscopic observations of the normal type Ia supernovae (SNe Ia) 2021pfs, which occurred in the Seyfert 2 galaxy NGC 5427 at a redshift 0.009. SN 2021pfs reached an absolute \textit{B}-band peak magnitude of M_max(B)=-19.28 ± 0.40 mag. The mag and a post-peak decline rate of Δm_15(B)=1.13 ± 0.06 mag. The observed properties of this nearby SN Ia closely resemble those of SN 2011fe, including the main optical spectroscopic features and photometric evolution. Despite their similar decline rates, SN 2021pfs rose more rapidly in the U band but more slowly in the r and i bands compared to SN 2011fe in very early phases. This photometric difference, particularly at short wavelengths, can introduce a systematic uncertainty of up to ∼12% in distance estimates. Analysis of the host galaxy's local and global environment shows an environment consistent with producing a higher-metallicity progenitor for SN 2021pfs than that of SN 2011fe.This higher progenitor metallicity may explain the observed photometric discrepancy and the resulting distance between SN 2021pfs and SN 2011fe, though a larger sample of such "twin" SNe Ia is needed to confirm this trend and assess its impact on cosmological measurements.
ER -