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- Title
The evolution of superluminous supernova LSQ14mo and its interacting host galaxy system.
- Authors
Chen, T.-W.; Nicholl, M.; Smartt, S. J.; Mazzali, P. A.; Yates, R. M.; Moriya, T. J.; Inserra, C.; Langer, N.; Krühler, T.; Pan, Y.-C.; Kotak, R.; Galbany, L.; Schady, P.; Wiseman, P.; Greiner, J.; Schulze, S.; Man, A. W. S.; Jerkstrand, A.; Smith, K. W.; Dennefeld, M.
- Abstract
We present and analyse an extensive dataset of the superluminous supernova (SLSN) LSQ14mo (z = 0:256), consisting of a multicolour light curve from -30 d to +70 d in the rest-frame (relative to maximum light) and a series of six spectra from PESSTO covering -7 d to +50 d. This is among the densest spectroscopic coverage, and best-constrained rising light curve, for a fast-declining hydrogen-poor SLSN. The bolometric light curve can be reproduced with a millisecond magnetar model with ~4 M⊙ ejecta mass, and the temperature and velocity evolution is also suggestive of a magnetar as the power source. Spectral modelling indicates that the SN ejected ~6 M⊙ of CO-rich material with a kinetic energy of ~7 × 1051 erg, and suggests a partially thermalised additional source of luminosity between -2 d and +22 d. This may be due to interaction with a shell of material originating from pre-explosion mass loss. We further present a detailed analysis of the host galaxy system of LSQ14mo. PESSTO and GROND imaging show three spatially resolved bright regions, and we used the VLT and FORS2 to obtain a deep (five-hour exposure) spectra of the SN position and the three star-forming regions, which are at a similar redshift. The FORS2 spectrum at +300 days shows no trace of SN emission lines and we place limits on the strength of [O i] from comparisons with other Ic supernovae. The deep spectra provides a unique chance to investigate spatial variations in the host star-formation activity and metallicity. The specific star-formation rate is similar in all three components, as is the presence of a young stellar population. However, the position of LSQ14mo exhibits a lower metallicity, with 12 + log(O=H) = 8:2 in both the R23 and N2 scales (corresponding to ~0.3 Z⊙). We propose that the three bright regions in the host system are interacting, which could induce gas flows triggering star formation in low-metallicity regions.
- Subjects
SUPERNOVAE; GALAXIES; STELLAR populations; LIGHT curves; GAS flow; STAR formation
- Publication
Astronomy & Astrophysics / Astronomie et Astrophysique, 2017, Vol 602, p1
- ISSN
0004-6361
- Publication type
Article
- DOI
10.1051/0004-6361/201630163