SN 2015bf: A fast declining type II supernova with flash-ionized signatures Academic Article uri icon


  • ABSTRACT We present optical and ultraviolet photometry, as well as optical spectra, for the type II supernova (SN) 2015bf. Our observations cover the phases from 2 to 200 d after explosion. The first spectrum is characterized by a blue continuum with a blackbody temperature of 24000K and flash-ionized emission lines. After about 1 week, the spectra of SN 2015bf evolve like those of a regular SN II. From the luminosity of the narrow emission component of H, we deduce that the mass-loss rate is larger than ${sim}3.7 imes 10^{-3}, {
    m M_odot , yr^{-1}}$. The disappearance of the flash features in the first week after explosion indicates that the circumstellar material is confined within 61014 cm. Thus, we suggest that the progenitor of SN 2015bf experienced violent mass loss shortly before the supernova explosion. The multiband light curves show that SN 2015bf has a high peak luminosity with an absolute visual magnitude MV= 18.110.08 mag and a fast post-peak decline with a V-band decay of 1.220.09 mag within 50 d after maximum light. Moreover, the R-band tail luminosity of SN 2015bf is fainter than that of SNeII with similar peak by 12 mag, suggesting a small amount of 56Ni (${sim}0.009, {
    m M_odot }$) synthesized during the explosion. Such a low nickel mass indicates that the progenitor of SN 2015bf could be a super-asymptotic-giant-branch star that collapsed owing to electron capture.

published proceedings


altmetric score

  • 29

author list (cited authors)

  • Lin, H., Wang, X., Zhang, J., Lin, W., Mo, J., Filippenko, A. V., ... Brink, T. G.

citation count

  • 2

complete list of authors

  • Lin, Han||Wang, Xiaofeng||Zhang, Jujia||Lin, Weili||Mo, Jun||Filippenko, Alexei V||Zheng, WeiKang||Brown, Peter J||Xiang, Danfeng||Huang, Fang||Cai, Yongzhi||Zhang, Tianmeng||Li, Xue||Rui, Liming||Zhang, Xinghan||Sai, Hanna||Zhao, Xulin||Graham, Melissa L||Shivvers, I||Halevi, G||Yuk, H||Brink, Thomas G

publication date

  • June 2021