Four (Super)Luminous Supernovae From the First Months of the ZTF Survey

R. Lunnan, Lin Yan, D. A. Perley, S. Schulze, K. Taggart, A. Gal-Yam, C. Fremling, M. T. Soumagnac, E. Ofek, S. M. Adams, C. Barbarino, E. C. Bellm, K. De, C. Fransson, S. Frederick, V. Z. Golkhou, M. J. Graham, N. Hallakoun, A. Y. Q. Ho, M. M. Kasliwal, S. Kaspi, S. R. Kulkarni, R. R. Laher, F. J. Masci, F. Pozo Nunez, B. Rusholme, R. M. Quimby, D. L. Shupe, J. Sollerman, F. Taddia, J. van Roestel, Y. Yang, Yuhan Yao

Published 2019-10-07Version 1

We present photometry and spectroscopy of four hydrogen-poor luminous supernovae discovered during the two-month science commissioning and early operations of the Zwicky Transient Facility (ZTF) survey. Three of these objects, SN2018bym (ZTF18aapgrxo), SN2018avk (ZTF18aaisyyp) and SN2018bgv (ZTF18aavrmcg) resemble typical SLSN-I spectroscopically, while SN2018don (ZTF18aajqcue) may be an object similar to SN2007bi experiencing considerable host galaxy reddening, or an intrinsically long-lived, luminous and red SN Ic. We analyze the light curves, spectra, and host galaxy properties of these four objects and put them in context of the population of SLSN-I. SN2018bgv stands out as the fastest-rising SLSN-I observed to date, with a rest-frame g-band rise time of just 10 days from explosion to peak -- if it is powered by magnetar spin-down, the implied ejecta mass is only ~1 M$_{\odot}$. SN2018don also displays unusual properties -- in addition to its red colors and comparatively massive host galaxy, the light curve undergoes some of the strongest light curve undulations post-peak seen in a SLSN-I, which we speculate may be due to interaction with circumstellar material. We discuss the promises and challenges of finding SLSNe in large-scale surveys like ZTF given the observed diversity in the population.