Two Years of Shock Interaction Tracing Three Phases of Evolution: The Explosion of a Type IIn Supernova, SN 2019vxm
8 affiliations
- 1Indian Institute of Astrophysics
- 2Academy of Scientific and Innovative Research (AcSIR)
- 3Shanghai Jiao Tong University
- 4Kagoshima University
- 5Kyoto University
- 6Hiroshima University
- 7Yunnan University
- 8Stockholm University
Abstract
We present multiwavelength photometric and optical spectroscopic observations of the long-lived interacting supernova SN 2019vxm, spanning more than 2 yr after the explosion. SN 2019vxm is a slowly rising (rise time ∼ 43 days in the R -band), slowly declining supernova reaching an R -band peak absolute magnitude of ≈−20.3 mag. The SN light curve postmaximum shows a shallow decline, followed by a secondary, steeper decline in the optical (∼0.01 mag day ⁻¹ ), with late-time IR brightening. The total radiated luminosity is 5 × 10 ⁵⁰ erg, placing it among the energetic class of its type. We estimated a CSM mass of 3–8 M ⊙ through light-curve modeling (independent of the CSM density profile) and by comparison with theoretical models. We estimate a minimum ejecta mass of ∼3.88 M ⊙ from the broad H α component, consistent with the ejecta mass obtained from the light-curve models. The solely interaction-dominated initial epochs are later accompanied by photon-scattering signatures, leading to asymmetric line profiles with symmetric wings. The late phase, characterized by enhanced brightness at longer wavelengths and a stronger asymmetric line profile with the red side flux strongly suppressed, indicates the influence of preexisting or newly formed dust with temperatures ∼1600 K at ∼4 × 10 ¹⁶ cm. Even in the late phases, no nebular lines are present in the spectra, indicating dense or obscured ejecta.
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BibTeX
@article{rameshan2026years,
title = {{Two Years of Shock Interaction Tracing Three Phases of Evolution: The Explosion of a Type IIn Supernova, SN 2019vxm}},
author = {Gitika Rameshan and Rishabh Singh Teja and D. K. Sahu and G. C. Anupama and Masayuki Yamanaka and Keiichi Maeda and Tatsuya Nakaoka and Sota Goto and Brajesh Kumar and Avinash Singh and Miho Kawabata and Koji S Kawabata and Kenta Taguchi},
journal = {The Astrophysical Journal},
year = {2026},
month = oct,
doi = {10.3847/1538-4357/aea5fd},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/aea5fd},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Two Years of Shock Interaction Tracing Three Phases of Evolution: The Explosion of a Type IIn Supernova, SN 2019vxm
AU - Gitika Rameshan
AU - Rishabh Singh Teja
AU - D. K. Sahu
AU - G. C. Anupama
AU - Masayuki Yamanaka
AU - Keiichi Maeda
AU - Tatsuya Nakaoka
AU - Sota Goto
AU - Brajesh Kumar
AU - Avinash Singh
AU - Miho Kawabata
AU - Koji S Kawabata
AU - Kenta Taguchi
PY - 2026
DA - 2026/10/19
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/aea5fd
UR - https://iopscience.iop.org/article/10.3847/1538-4357/aea5fd
AB - We present multiwavelength photometric and optical spectroscopic observations of the long-lived interacting supernova SN 2019vxm, spanning more than 2 yr after the explosion. SN 2019vxm is a slowly rising (rise time ∼ 43 days in the R -band), slowly declining supernova reaching an R -band peak absolute magnitude of ≈−20.3 mag. The SN light curve postmaximum shows a shallow decline, followed by a secondary, steeper decline in the optical (∼0.01 mag day ⁻¹ ), with late-time IR brightening. The total radiated luminosity is 5 × 10 ⁵⁰ erg, placing it among the energetic class of its type. We estimated a CSM mass of 3–8 M ⊙ through light-curve modeling (independent of the CSM density profile) and by comparison with theoretical models. We estimate a minimum ejecta mass of ∼3.88 M ⊙ from the broad H α component, consistent with the ejecta mass obtained from the light-curve models. The solely interaction-dominated initial epochs are later accompanied by photon-scattering signatures, leading to asymmetric line profiles with symmetric wings. The late phase, characterized by enhanced brightness at longer wavelengths and a stronger asymmetric line profile with the red side flux strongly suppressed, indicates the influence of preexisting or newly formed dust with temperatures ∼1600 K at ∼4 × 10 ¹⁶ cm. Even in the late phases, no nebular lines are present in the spectra, indicating dense or obscured ejecta.
SN - 0004-637X
SN - 1538-4357
ER -