Aydi, E. and Page, K. L. and Kuin, N. P. M. and Darnley, M. J. and Walter, F. M. and Mróz, P. and Buckley, D. and Mohamed, S. and Whitelock, P. and Woudt, P. and Williams, S. C. and Orio, M. and Williams, R. E. and Beardmore, A. P. and Osborne, J. P. and Kniazev, A. and Ribeiro, V. A. R. M. and Udalski, A. and Strader, J. and Chomiuk, L. (2018) Multiwavelength observations of nova SMCN 2016-10a -- one of the brightest novae ever observed. Monthly Notices of the Royal Astronomical Society, 474 (2). pp. 2679-2705. ISSN 0035-8711
Abstract
We report on multiwavelength observations of nova SMCN 2016-10a. The present observational set is one of the most comprehensive for any nova in the Small Magellanic Cloud, including: low, medium, and high resolution optical spectroscopy and spectropolarimetry from SALT, FLOYDS, and SOAR; long-term OGLE $V$- and $I$- bands photometry dating back to six years before eruption; SMARTS optical and near-IR photometry from $\sim$ 11 days until over 280 days post-eruption; $Swift$ satellite X-ray and ultraviolet observations from $\sim$ 6 days until 319 days post-eruption. The progenitor system contains a bright disk and a main sequence or a sub-giant secondary. The nova is very fast with $t_2 \simeq$ 4.0 $\pm$ 1.0 d and $t_3 \simeq$ 7.8 $\pm$ 2.0 d in the $V$-band. If the nova is in the SMC, at a distance of $\sim$ 61 $\pm$ 10 kpc, we derive $M_{V,\mathrm{max}} \simeq - 10.5$ $\pm$ 0.5, making it the brightest nova ever discovered in the SMC and one of the brightest on record. At day 5 post-eruption the spectral lines show a He/N spectroscopic class and a FWHM of $\sim$ 3500 kms$^{-1}$ indicating moderately high ejection velocities. The nova entered the nebular phase $\sim$ 20 days post-eruption, predicting the imminent super-soft source turn-on in the X-rays, which started $\sim$ 28 days post-eruption. The super-soft source properties indicate a white dwarf mass between 1.2 M$_{\odot}$ and 1.3 M$_{\odot}$ in good agreement with the optical conclusions.