Intermediate-luminosity Type IIP SN 2021gmj : a low-energy explosion with signatures of circumstellar material

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2024-03-01
Major/Subject
Mcode
Degree programme
Language
en
Pages
19
Series
Monthly Notices of the Royal Astronomical Society, Volume 528, issue 3, pp. 4209-4227
Abstract
We present photometric, spectroscopic, and polarimetric observations of the intermediate-luminosity Type IIP supernova (SN) 2021gmj from 1 to 386 d after the explosion. The peak absolute V-band magnitude of SN 2021gmj is −15.5 mag, which is fainter than that of normal Type IIP SNe. The spectral evolution of SN 2021gmj resembles that of other sub-luminous SNe: The optical spectra show narrow P-Cygni profiles, indicating a low expansion velocity. We estimate the progenitor mass to be about 12 M⊙ from the nebular spectrum and the 56Ni mass to be about 0.02 M⊙ from the bolometric light curve. We also derive the explosion energy to be about 3 × 1050 erg by comparing numerical light-curve models with the observed light curves. Polarization in the plateau phase is not very large, suggesting nearly spherical outer envelope. The early photometric observations capture the rapid rise of the light curve, which is likely due to the interaction with a circumstellar material (CSM). The broad emission feature formed by highly ionized lines on top of a blue continuum in the earliest spectrum gives further indication of the CSM at the vicinity of the progenitor. Our work suggests that a relatively low-mass progenitor of an intermediate-luminosity Type IIP SN can also experience an enhanced mass-loss just before the explosion, as suggested for normal Type IIP SNe.
Description
Publisher Copyright: © 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.
Keywords
supernovae: general – supernovae: individual: SN 2021gmj
Other note
Citation
Murai, Y, Tanaka, M, Kawabata, M, Taguchi, K, Teja, R S, Nakaoka, T, Maeda, K, Kawabata, K S, Nagao, T, Moriya, T J, Sahu, D K, Anupama, G C, Tominaga, N, Morokuma, T, Imazawa, R, Inutsuka, S, Isogai, K, Kasuga, T, Kobayashi, N, Kondo, S, Maehara, H, Mori, Y, Niino, Y, Ogawa, M, Ohsawa, R, Okumura, S I, Saito, S, Sako, S, Takahashi, H, Uno, K & Yamanaka, M 2024, ' Intermediate-luminosity Type IIP SN 2021gmj : a low-energy explosion with signatures of circumstellar material ', Monthly Notices of the Royal Astronomical Society, vol. 528, no. 3, pp. 4209-4227 . https://doi.org/10.1093/mnras/stae170