_version_ 1866917072351526912
author Zou, Xingzhu
Kumar, Brajesh
Teja, Rishabh Singh
Sahu, D. K.
Chen, Xinlei
Singh, Avinash
Lin, Weikang
Liu, Xiangkun
Liu, Dezi
Das, Hrishav
Singh, Mridweeka
Anupama, G. C.
Pan, Yu
Du, Guowang
Guo, Helong
Wang, Tao
Zhu, Xufeng
Zhang, Jujia
Fang, Yuan
Liu, Chenxu
Chatterjee, Kaushik
Yang, Yuan-Pei
Li, Liping
Zhai, Qian
Lagioia, Edoardo P.
Du, Xueling
Er, Xinzhong
Lian, Jianhui
Li, Ziwei
Zhong, Shiyan
Liu, Xiaowei
author_facet Zou, Xingzhu
Kumar, Brajesh
Teja, Rishabh Singh
Sahu, D. K.
Chen, Xinlei
Singh, Avinash
Lin, Weikang
Liu, Xiangkun
Liu, Dezi
Das, Hrishav
Singh, Mridweeka
Anupama, G. C.
Pan, Yu
Du, Guowang
Guo, Helong
Wang, Tao
Zhu, Xufeng
Zhang, Jujia
Fang, Yuan
Liu, Chenxu
Chatterjee, Kaushik
Yang, Yuan-Pei
Li, Liping
Zhai, Qian
Lagioia, Edoardo P.
Du, Xueling
Er, Xinzhong
Lian, Jianhui
Li, Ziwei
Zhong, Shiyan
Liu, Xiaowei
contents We present the results of low-resolution spectroscopic and densely sampled multi-band photometric follow-up of supernova (SN) 2024aecx. The SN was discovered in the spiral galaxy NGC 3521 (distance $\sim$11 Mpc) within a day after the explosion. The early spectra of SN 2024aecx show a weak signature of hydrogen lines, which disappeared in $\sim$30 days after the explosion. Light curves in all bands show a distinct feature of two peaks, and the first peak is likely due to the shock cooling emission. The early phase light curve evolution of SN 2024aecx has similarity with the typical Type IIb events, but the decay rate in different bands (e.g., $\rm Δm_{15}$ = 1.60 $\pm$ 0.05 mag, $g$-band) is significantly faster in the post-peak phase. It attained the secondary maximum in $\sim$19 days ($g$-band) with a peak absolute magnitude of M$_{g}$ = -17.94 $\pm$ 0.10 mag. SN 2024aecx colors trend redder in early epochs ($<$8 days), followed by a duration in which it grows bluer, then later gets redder again $>$20 days after explosion. The analytical model fitting to the light curves reveals an envelope mass and progenitor radii in the range of $\sim$0.03 - 0.24 $M_\odot$ and $\sim$169 - 200 $R_\odot$, respectively. Modeling of the pseudo-bolometric light curve suggests that synthesized $^{56}$Ni in the explosion was $\sim$0.15 M$_{\odot}$ with ejecta mass and kinetic energy of $\sim$0.7 M$_{\odot}$ and $\sim$0.16 $\times$ 10$^{51}$ erg, respectively. The observational properties and modeling indicate that the SN~2024aecx progenitor belongs to the extended progenitor category.
format Preprint
id arxiv_https___arxiv_org_abs_2505_19831
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle SN 2024aecx: A double-peaked rapidly evolving Type IIb supernova at 11 Mpc
Zou, Xingzhu
Kumar, Brajesh
Teja, Rishabh Singh
Sahu, D. K.
Chen, Xinlei
Singh, Avinash
Lin, Weikang
Liu, Xiangkun
Liu, Dezi
Das, Hrishav
Singh, Mridweeka
Anupama, G. C.
Pan, Yu
Du, Guowang
Guo, Helong
Wang, Tao
Zhu, Xufeng
Zhang, Jujia
Fang, Yuan
Liu, Chenxu
Chatterjee, Kaushik
Yang, Yuan-Pei
Li, Liping
Zhai, Qian
Lagioia, Edoardo P.
Du, Xueling
Er, Xinzhong
Lian, Jianhui
Li, Ziwei
Zhong, Shiyan
Liu, Xiaowei
High Energy Astrophysical Phenomena
We present the results of low-resolution spectroscopic and densely sampled multi-band photometric follow-up of supernova (SN) 2024aecx. The SN was discovered in the spiral galaxy NGC 3521 (distance $\sim$11 Mpc) within a day after the explosion. The early spectra of SN 2024aecx show a weak signature of hydrogen lines, which disappeared in $\sim$30 days after the explosion. Light curves in all bands show a distinct feature of two peaks, and the first peak is likely due to the shock cooling emission. The early phase light curve evolution of SN 2024aecx has similarity with the typical Type IIb events, but the decay rate in different bands (e.g., $\rm Δm_{15}$ = 1.60 $\pm$ 0.05 mag, $g$-band) is significantly faster in the post-peak phase. It attained the secondary maximum in $\sim$19 days ($g$-band) with a peak absolute magnitude of M$_{g}$ = -17.94 $\pm$ 0.10 mag. SN 2024aecx colors trend redder in early epochs ($<$8 days), followed by a duration in which it grows bluer, then later gets redder again $>$20 days after explosion. The analytical model fitting to the light curves reveals an envelope mass and progenitor radii in the range of $\sim$0.03 - 0.24 $M_\odot$ and $\sim$169 - 200 $R_\odot$, respectively. Modeling of the pseudo-bolometric light curve suggests that synthesized $^{56}$Ni in the explosion was $\sim$0.15 M$_{\odot}$ with ejecta mass and kinetic energy of $\sim$0.7 M$_{\odot}$ and $\sim$0.16 $\times$ 10$^{51}$ erg, respectively. The observational properties and modeling indicate that the SN~2024aecx progenitor belongs to the extended progenitor category.
title SN 2024aecx: A double-peaked rapidly evolving Type IIb supernova at 11 Mpc
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2505.19831