Light curve and spectral evolution of the Type IIb supernova 2011fu

• Published in: Monthly notices of the Royal Astronomical Society Vol. 431; no. 1; pp. 308 - 321
• Main Authors: Kumar, Brajesh, Pandey, S. B., Sahu, D. K., Vinko, J., Moskvitin, A. S., Anupama, G. C., Bhatt, V. K., Ordasi, A., Nagy, A., Sokolov, V. V., Sokolova, T. N., Komarova, V. N., Kumar, Brijesh, Bose, Subhash, Roy, Rupak, Sagar, Ram
• Format: Journal Article
• Language: English
• Published: London Oxford University Press 01.05.2013
• Subjects: Astronomy; Star & galaxy formation; Supernovae; galaxies: individual (UGC 01626); supernovae: general; supernovae: individual (SN 1993J); supernovae: individual: SN 2011fu
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stt162

We present the low-resolution spectroscopic and UBVRI broad-band photometric investigations of the Type IIb supernova (SN) 2011fu, discovered in UGC 01626. The photometric follow-up of this event was initiated a few days after the explosion and covers a period of about 175 d. The early-phase light curve shows a rise, followed by steep decay in all bands, and shares properties very similar to that seen for SN 1993J, with a possible detection of the adiabatic cooling phase. Modelling of the quasi-bolometric light curve suggests that the progenitor had an extended (∼1 × 1013 cm), low-mass (∼0.1 M) H-rich envelope on top of a dense, compact (∼2 × 1011 cm), more massive (∼1.1 M) He-rich core. The nickel mass synthesized during the explosion was found to be ∼0.21 M, slightly larger than that seen for other Type IIb SNe. The spectral modelling performed with synow suggests that the early-phase line velocities for H and Fe ii features were ∼16 000 and ∼14 000 km s−1, respectively. Then, the velocities declined up to day +40 and became nearly constant at later epochs.