Discovery and Rapid Follow-up Observations of the Unusual Type II SN 2018ivc in NGC 1068
Metadatos
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The American Astronomical Society
Materia
Circumstellar gas Core-collapse supernovae Type II supernovae Animation Machine-readable table
Fecha
2020-05Referencia bibliográfica
Bostroem, K. A., Valenti, S., Sand, D. J., Andrews, J. E., Van Dyk, S. D., Galbany, L., ... & Anupama, G. C. (2020). Discovery and Rapid Follow-up Observations of the Unusual Type II SN 2018ivc in NGC 1068. The Astrophysical Journal, 895(1), 31. [https://doi.org/10.3847/1538-4357/ab8945]
Resumen
We present the discovery and high-cadence follow-up observations of SN 2018ivc, an unusual SNe II that
exploded in NGC 1068 (D = 10.1 Mpc). The light curve of SN 2018ivc declines piecewise-linearly, changing
slope frequently, with four clear slope changes in the first 30 days of evolution. This rapidly changing light
curve indicates that interaction between the circumstellar material and ejecta plays a significant role in the
evolution. Circumstellar interaction is further supported by a strong X-ray detection. The spectra are rapidly
evolving and dominated by hydrogen, helium, and calcium emission lines. We identify a rare high-velocity
emission-line feature blueshifted at ∼7800 - km s 1 (in Hα, Hβ, Pβ, Pγ, He I, and Ca II), which is visible from
day 18 until at least day 78 and could be evidence of an asymmetric progenitor or explosion. From the overall
similarity between SN 2018ivc and SN 1996al, the Hα equivalent width of its parent H II region, and
constraints from pre-explosion archival Hubble Space Telescope images, we find that the progenitor of
SN 2018ivc could be as massive as 52 M but is more likely <12 M. SN 2018ivc demonstrates the importance
of the early discovery and rapid follow-up observations of nearby supernovae to study the physics and
progenitors of these cosmic explosions.