The evolution of the 3D shape of the broad-lined type Ic SN 2014ad

Abstract

We present optical spectropolarimetry and spectroscopy of the broad-lined Type Ic (Ic-bl) SN 2014ad. Our spectropolarimetric observations cover 7 epochs, from -2 days to 66 days after V-band maximum, and the spectroscopic data were acquired from -2 days to +107 days. The photospheric velocity estimates showed ejecta speeds similar to those of SN 1998bw and other SNe associated with GRBs. The spectropolarimetric data revealed aspherical outer ejecta and a nearly spherical interior. The polarisation 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.

Accepted for publication in MNRAS - 17 pages, 16 Figures

References in corpus (19)

• Physical Properties of Wolf-Rayet Stars
• Spectropolarimetry of Supernovae
• Measured Metallicities at the Sites of Nearby Broad-Lined Type Ic Supernovae and Implications for the SN-GRB Connection
• Asphericity in Supernova Explosions from Late-Time Spectroscopy
• A non-spherical core in the explosion of supernova SN 2004dj
• The Northern HIPASS catalogue - Data presentation, completeness and reliability measures
• Supernova 2006aj and the associated X-Ray Flash 060218
• Polarisation studies of the prompt gamma-ray emission from GRB 041219a using the Spectrometer aboard INTEGRAL
• Progenitor Diagnostics for Stripped Core-Collapse Supernovae: Measured Metallicities at Explosion Sites
• Analysis of Late--time Light Curves of Type IIb, Ib and Ic Supernovae
• On the nature of nearby GRB/SN host galaxies
• Spatially resolved properties of the GRB 060505 host: implications for the nature of the progenitor
• Detection of Wolf-Rayet stars in host galaxies of Gamma-Ray Bursts (GRBs): are GRBs produced by runaway massive stars ejected from high stellar density regions ?
• Spectropolarimetry of the Type Ib/c SN 2005bf
• A Revised Host Galaxy Association for GRB 020819B: A High-Redshift Dusty Starburst, Not a Low-Redshift Gas-Poor Spiral
• Spectropolarimetry of SN 2006aj at 9.6 days
• Models of Forbidden Line Emission Profiles from Axisymmetric Stellar Winds
• Spectropolarimetry of the Type IIb SN 2008aq
• Optical spectropolarimetry with incomplete data sets

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