Chen, TW, Nicholl, M, Smartt, SJ, Mazzali, PA, Yates, RM, Moriya, TJ, Inserra, C, Langer, N, Krühler, T, Pan, YC, Kotak, R, Galbany, L, Schady, P, Wiseman, P, Greiner, J, Schulze, S, Man, AWS, Jerkstrand, A, Smith, KW, Dennefeld, M et al, Baltay, C, Bolmer, J, Kankare, E, Knust, F, Maguire, K, Rabinowitz, D, Rostami, S, Sullivan, M and Young, DR (2017) The evolution of superluminous supernova LSQ14mo and its interacting host galaxy system. Astronomy and Astrophysics, 602. ISSN 0004-6361

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Abstract

We present and analyse an extensive dataset of the superluminous supernova (SLSN) LSQ14mo (z = 0.256), consisting of a multi-colour 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. © ESO, 2017.

Item Type:	Article
Uncontrolled Keywords:	0201 Astronomical And Space Sciences
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	EDP Sciences
Date Deposited:	18 Oct 2017 10:11
Last Modified:	04 Sep 2021 03:42
DOI or ID number:	10.1051/0004-6361/201630163
URI:	https://researchonline.ljmu.ac.uk/id/eprint/7372

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