http://arxiv.org/abs/1808.04382
We present observations of supernova (SN) 2017ens, discovered by the ATLAS survey and identified as a hot blue object through the GREAT program. The redshift z=0.1086 implies a peak brightness of M_g=-21.1 mag, placing the object within the regime of superluminous supernovae. We observe dramatic spectral evolution, from initially being blue and featureless, to later developing features similar to those of the broad-lined Type Ic SN 1998bw, to eventually showing broad H-alpha and H-beta emission, together with relatively narrow emission (reminiscent of a SN IIn) in all periods. We also detect coronal lines, indicative of a dense circumstellar medium. We constrain the progenitor wind velocity to ~50-60 km s^-1 based on P-Cygni profiles, which is far slower than those present in Wolf-Rayet stars. This may suggest that the progenitor passed through a luminous blue variable phase, or that the wind is instead from a binary companion red supergiant star. At late times we see broad (~2000 km s^-1) and strong (~3×10^40 erg s^-1) H-alpha emission, perhaps indicative of additional mass loss at high velocity, suggesting that SN 2017ens was a pulsational pair-instability SN.
T. Chen, C. Inserra, M. Fraser, et. al.
Wed, 15 Aug 18
41/69
Comments: 14 pages, 4 figures, 7 tables. Submitted to ApJL. Comments are welcome!