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arXiv · 1705.00344

Discovery of a rapid, luminous nova in NGC 300 by the KMTNet Supernova Program

John Antoniadis·Dae-Sik Moon·Yuan Qi Ni·Dong-Jin Kim·Yongseok Lee·Hilding Neilson
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Abstract

We present the discovery of a rapidly evolving transient by the Korean Microlensing Telescope Network Supernova Program (KSP). KSP is a novel high-cadence supernova survey that offers deep ($\sim21.5$ mag in $BVI$ bands) nearly continuous wide-field monitoring for the discovery of early and/or fast optical transients. KSP-OT-201509a, reported here, was discovered on 2015 September 27 during the KSP commissioning run in the direction of the nearby galaxy NGC~300, and stayed above detection limit for $\sim$ 22 days. We use our $BVI$ light-curves to constrain the ascent rate, $-3.7(7)$ mag day$^{-1}$ in $V$, decay time scale, $t^{V}_{2}=1.7(6)$ days, and peak absolute magnitude, $-9.65\leq M_{V}\leq -9.25$ mag. We also find evidence for a short-lived pre-maximum halt in all bands. The peak luminosity and lightcurve evolution make KSP-OT-201509a consistent with a bright, rapidly decaying nova outburst. We discuss constraints on the nature of the progenitor and its environment using archival HST/ACS images and conclude with a broad discussion on the nature of the system.

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John Antoniadis, Dae-Sik Moon, Yuan Qi Ni, Dong-Jin Kim, Yongseok Lee, Hilding Neilson. 2017-04-30. Discovery of a rapid, luminous nova in NGC 300 by the KMTNet Supernova Program. https://doi.org/10.3847/1538-4357/aa706b

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