TY - JOUR
T1 - PTF11iqb: cool supergiant mass-loss that bridges the gap between Type IIn and normal supernovae
AU - Smith, Nathan
AU - Mauerhan, Jon C.
AU - Cenko, S. Bradley
AU - Kasliwal, Mansi M.
AU - Silverman, Jeffrey M.
AU - Filippenko, Alexei V.
AU - Gal-Yam, Avishay
AU - Clubb, Kelsey I.
AU - Graham, Melissa L.
AU - Leonard, Douglas C.
AU - Horst, J. Chuck
AU - Williams, G. Grant
AU - Andrews, Jennifer E.
AU - Kulkarni, Shrinivas R.
AU - Nugent, Peter
AU - Sullivan, Mark
AU - Maguire, Kate
AU - Xu, Dong
AU - Ben-Ami, Sagi
PY - 2015/5/11
Y1 - 2015/5/11
N2 - PTF11iqb was initially classified as a TypeIIn event caught very early after explosion. It showed narrow Wolf-Rayet (WR) spectral features on day 2, but the narrow emission weakened quickly and the spectrum morphed to resemble those of Types II-L and II-P. At late times, Halpha emission exhibited a complex, multipeaked profile reminiscent of SN1998S. In terms of spectroscopic evolution, we find that PTF11iqb was a near twin of SN~1998S, although with weaker interaction with circumstellar material (CSM) at early times, and stronger CSM interaction at late times. We interpret the spectral changes as caused by early interaction with asymmetric CSM that is quickly (by day 20) enveloped by the expanding SN ejecta photosphere, but then revealed again after the end of the plateau when the photosphere recedes. The light curve can be matched with a simple model for weak CSM interaction added to the light curve of a normal SN~II-P. This plateau requires that the progenitor had an extended H envelope like a red supergiant, consistent with the slow progenitor wind speed indicated by narrow emission. The cool supergiant progenitor is significant because PTF11iqb showed WR features in its early spectrum --- meaning that the presence of such WR features in an early SN spectrum does not necessarily indicate a WR-like progenitor. [abridged] Overall, PTF11iqb bridges SNe~IIn with weaker pre-SN mass loss seen in SNe II-L and II-P, implying a continuum between these types.
AB - PTF11iqb was initially classified as a TypeIIn event caught very early after explosion. It showed narrow Wolf-Rayet (WR) spectral features on day 2, but the narrow emission weakened quickly and the spectrum morphed to resemble those of Types II-L and II-P. At late times, Halpha emission exhibited a complex, multipeaked profile reminiscent of SN1998S. In terms of spectroscopic evolution, we find that PTF11iqb was a near twin of SN~1998S, although with weaker interaction with circumstellar material (CSM) at early times, and stronger CSM interaction at late times. We interpret the spectral changes as caused by early interaction with asymmetric CSM that is quickly (by day 20) enveloped by the expanding SN ejecta photosphere, but then revealed again after the end of the plateau when the photosphere recedes. The light curve can be matched with a simple model for weak CSM interaction added to the light curve of a normal SN~II-P. This plateau requires that the progenitor had an extended H envelope like a red supergiant, consistent with the slow progenitor wind speed indicated by narrow emission. The cool supergiant progenitor is significant because PTF11iqb showed WR features in its early spectrum --- meaning that the presence of such WR features in an early SN spectrum does not necessarily indicate a WR-like progenitor. [abridged] Overall, PTF11iqb bridges SNe~IIn with weaker pre-SN mass loss seen in SNe II-L and II-P, implying a continuum between these types.
KW - Astrophysics - High Energy Astrophysical Phenomena
KW - Astrophysics - Solar and Stellar Astrophysics
U2 - 10.1093/mnras/stv354
DO - 10.1093/mnras/stv354
M3 - Article
SN - 0035-8711
VL - 449
SP - 1876
EP - 1896
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -