科研之友
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摘要
A nova in the Local Group irregular dwarf galaxy IC 1613 was discovered on 2015 September 10 and is the first nova in that galaxy to be spectroscopically confirmed. We conducted a detailed multiwavelength observing campaign of the eruption with the Liverpool Telescope, the LCO 2 m telescope at Siding Spring Observatory, and Swift, the results of which we present here. The nova peaked at MV = -7.93 +/- 0.08 and was fast-fading, with decline times of t(2(V)) = 13 +/- 2 and t(3(V)) = 26 +/- 2 d. The overall light-curve decline was relatively smooth, as often seen in fast-fading novae. Swift observations spanned 40-332 d post-discovery, but no X-ray source was detected. Optical spectra show the nova to be a member of the hybrid spectroscopic class, simultaneously showing Fe II and N II lines of similar strength during the early decline phase. The spectra cover the eruption from the early optically thick phase, through the early decline and into the nebular phase. The H gamma absorption minimum from the optically thick spectrum indicates an expansion velocity of 1200 +/- 200 km s(-1). The full width at half-maximum of the H alpha emission line between 10.54 and 57.51 d post-iscovery shows no significant evolution and remains at similar to 1750 km s(-1), although the morphology of this line does show some evolution. The nova appears close to a faint stellar source in archival imaging; however, we find the most likely explanation for this is simply a chance alignment.
- 出版日期2017-12
