Stevance, H.F., Maund, J.R. orcid.org/0000-0003-0733-7215, Baade, D. et al. (7 more authors) (2017) The evolution of the 3D shape of the broad-lined type Ic SN 2014ad. Monthly Notices of the Royal Astronomical Society, 469 (2). pp. 1897-1911. ISSN 0035-8711
Abstract
We present optical spectropolarimetry and spectroscopy of the broad-lined Type Ic (Ic-bl) SN 2014ad. Our spectropolarimetric observations cover seven epochs, from −2 to 66 d after V-band maximum, and the spectroscopic data were acquired from −2 to +107 d. The photospheric velocity estimates showed ejecta speeds similar to those of SN 1998bw and other SNe associated with gamma-ray bursts (GRBs). The spectropolarimetric data revealed aspherical outer ejecta and a nearly spherical interior. The polarization associated with O I λ7774 and the Ca II infrared triplet suggests a clumpy and highly asymmetrical distribution of these two species within the ejecta. Furthermore, it was shown that the two line forming regions must have been spatially distinct and oxygen was found to have higher velocities than calcium. Another oxygen line-forming region was also identified much closer to the core of the explosion and distributed in a spherical shell. It is difficult to reconcile the geometry of the deeper ejecta with a jet driven explosion, but the high ejecta velocities of SN 2014ad are typical of those observed in SNe Ic-bl with GRBs and the behaviour of the oxygen and calcium line-forming regions is consistent with fully jet-driven models. The metallicity of the host galaxy of SN 2014ad was also calculated and compared to that of the hosts of other SNe Ic-bl with and without GRBs, but due to the overlap in the two populations no conclusion could be drawn.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Keywords: | techniques: polarimetric; gamma-ray burst: general – supernovae: general; supernovae: individual: 2014ad |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Funding Information: | Funder Grant number ROYAL SOCIETY UF100736 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 12 Jul 2017 11:39 |
Last Modified: | 27 Oct 2023 10:14 |
Status: | Published |
Publisher: | Oxford University Press |
Refereed: | Yes |
Identification Number: | 10.1093/mnras/stx970 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:118766 |