Flash Ionization Signatures in the Type Ibn Supernova SN 2019uo
Anjasha Gangopadhyay, Kuntal Misra, Daichi Hiramatsu, Shan-Qin Wang, Griffin Hosseinzadeh, Xiaofeng Wang, Stefano Valenti, Jujia Zhang, D. Andrew Howell, Iair Arcavi, G. C. Anupama, Jamison Burke, Raya Dastidar, Koichi Itagaki, Brajesh Kumar, Brijesh Kumar, Long Li, Curtis McCully, Jun Mo, Shashi Bhushan Pandey, Craig Pellegrino, Hanna Sai, D. K. Sahu, Pankaj Sanwal, Avinash Singh, Mridweeka Singh, Jicheng Zhang, Tianmeng Zhang, Xinhan Zhang
Abstract
Abstract We present photometric and spectroscopic observations of the type Ibn supernova (SN) 2019uo, the second ever SN Ibn with flash ionization (He ii , C iii , N iii ) features in its early spectra. SN 2019uo displays a rapid post-peak luminosity decline of 0.1 mag day −1 similar to most of the SNe Ibn, but is fainter ( mag) than a typical SN Ibn and shows a color evolution that places it between SNe Ib and the most extreme SNe Ibn. SN 2019uo shows P-cygni He i features in the early spectra which gradually evolve and become emission dominated post peak. It also shows faster evolution in line velocities as compared to most other members of the type Ibn subclass. The bolometric light curve is fairly well described by a 56 Ni + circumstellar interaction model.