A Hubble Space Telescope survey of the host galaxies of Superluminous Supernovae
We present Hubble Space Telescope (HST) Wide Field Camera 3 UV and near-IR (nIR) imaging of 21 Superluminous Supernovae (SLSNe) host galaxies, providing a sensitive probe of star formation and stellar mass within the hosts. Comparing the photometric and morphological properties of these host galaxies with those of core-collapse supernovae (CCSNe) and long-duration gamma-ray bursts (LGRBs), we find SLSN hosts are fainter and more compact at both UV and nIR wavelengths, in some cases we barely recover hosts with absolute magnitude around M_V ≈ −14. With the addition of ground based optical observations and archival results, we produce spectral energy distribution fits to these hosts, and show that SLSN hosts possess lower stellar mass and star formation rates. This is most pronounced for the hydrogen deficient Type-I SLSN hosts, although Type-II H-rich SLSN host galaxies remain distinct from the bulk of CCSNe, spanning a remarkably broad range of absolute magnitudes, with ∼30 per cent of SLSNe-II arising from galaxies fainter than M_(nIR) ∼ −14. The detection of our faintest SLSN hosts increases the confidence that SLSNe-I hosts are distinct from those of LGRBs in star formation rate and stellar mass, and suggests that apparent similarities in metallicity may be due to the limited fraction of hosts for which emission line metallicity measurements are feasible. The broad range of luminosities of SLSN-II hosts is difficult to describe by metallicity cuts, and does not match the expectations of any reasonable UV-weighted luminosity function, suggesting additional environmental constraints are likely necessary to yield hydrogen rich SLSNe.
© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 January 7. Received 2016 January 7. In original form 2015 September 4. First published online March 4, 2016. CRA acknowledges receipt of a studentship from the Midlands Physics Alliance. AJL thanks STFC for support under grant ID ST/I001719/1, and the Leverhulme Trust for support via a Philip Leverhulme Prize. We are grateful to the PTF group (in particular Robert Quimby and Avishay Gal-Yam) for providing six images for SNe for astrometric purposes. ALJ, JDL and ERS are grateful for the support of STFC Warwick Astrophysics consolidated grant ID ST/L000733/1. Based on observations made with the NASA/ESA HST, obtained at the STScI, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program GO-13025 and GO-13480. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 092.D-0815. Optical data were obtained from the WHT under service mode programme SW2012b31.
Published - MNRAS-2016-Angus-84-104.pdf