Supernova 2013fc in a circumnuclear ring of a luminous infrared galaxy: the big brother of SN 1998S

• Published in: Monthly notices of the Royal Astronomical Society 2016-02, Vol.456 (1), p.323-346
• Main Authors: Kangas, T., Mattila, S., Kankare, E., Lundqvist, P., Väisänen, P., Childress, M., Pignata, G., McCully, C., Valenti, S., Vinkó, J., Pastorello, A., Elias-Rosa, N., Fraser, M., Gal-Yam, A., Kotak, R., Kotilainen, J. K., Smartt, S. J., Galbany, L., Harmanen, J., Howell, D. A., Inserra, C., Marion, G. H., Quimby, R. M., Silverman, J. M., Szalai, T., Wheeler, J. C., Ashall, C., Benetti, S., Romero-Cañizales, C., Smith, K. W., Sullivan, M., Takáts, K., Young, D. R.
• Format: Article
• Language: English
• Subjects: 2013fc-galaxies; Brightness; Comparative analysis; Galaxies; general-supernovae; individual; Infrared photometry; Luminosity; Photometry; Spectroscopy; Star & galaxy formation; starburst; Supernovae; Symbols; Trapping
• ISSN: 0035-8711; 1365-2966; 1365-2966
• DOI: 10.1093/mnras/stv2567

We present photometric and spectroscopic observations of SN 2013fc, a bright type II supernova (SN) in a circumnuclear star-forming ring in the luminous infrared galaxy ESO 154-G010, observed as part of the Public ESO Spectroscopic Survey of Transient Objects. SN 2013fc is both photometrically and spectroscopically similar to the well-studied type IIn SN 1998S and to the bright type II-L SN 1979C. It exhibits an initial linear decline, followed by a short plateau phase and a tail phase with a decline too fast for 56Co decay with full γ-ray trapping. Initially, the spectrum was blue and featureless. Later on, a strong broad (∼8000 km s−1) H α emission profile became prominent. We apply a starlight stellar population model fit to the SN location (observed when the SN had faded) to estimate a high extinction of A V = 2.9 ± 0.2 mag and an age of $10_{-2}^{+3}$  Myr for the underlying cluster. We compare the SN to SNe 1998S and 1979C and discuss its possible progenitor star considering the similarities to these events. With a peak brightness of B = −20.46 ± 0.21 mag, SN 2013fc is 0.9 mag brighter than SN 1998S and of comparable brightness to SN 1979C. We suggest that SN 2013fc was consistent with a massive red supergiant (RSG) progenitor. Recent mass loss probably due to a strong RSG wind created the circumstellar matter illuminated through its interaction with the SN ejecta. We also observe a near-infrared excess, possibly due to newly condensed dust.