SN 2014ab: An Aspherical Type IIn Supernova with Low Polarization. (arXiv:2007.12134v1 [astro-ph.SR])

SN 2014ab: An Aspherical Type IIn Supernova with Low Polarization. (arXiv:2007.12134v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bilinski_C/0/1/0/all/0/1">Christopher Bilinski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smith_N/0/1/0/all/0/1">Nathan Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Williams_G/0/1/0/all/0/1">G. Grant Williams</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smith_P/0/1/0/all/0/1">Paul Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Andrews_J/0/1/0/all/0/1">Jennifer Andrews</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clubb_K/0/1/0/all/0/1">Kelsey I. Clubb</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zheng_W/0/1/0/all/0/1">WeiKang Zheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Filippenko_A/0/1/0/all/0/1">Alexei V. Filippenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fox_O/0/1/0/all/0/1">Ori D. Fox</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hosseinzadeh_G/0/1/0/all/0/1">Griffin Hosseinzadeh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Howell_D/0/1/0/all/0/1">D. Andrew Howell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kelly_P/0/1/0/all/0/1">Patrick L. Kelly</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cargill_S/0/1/0/all/0/1">Samantha Cargill</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Casper_C/0/1/0/all/0/1">Chadwick Casper</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Halevy_G/0/1/0/all/0/1">Goni Halevy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_H/0/1/0/all/0/1">Haejung Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kumar_S/0/1/0/all/0/1">Sahana Kumar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pina_K/0/1/0/all/0/1">Kenia Pina</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yuk_H/0/1/0/all/0/1">Heechan Yuk</a>

We present photometry, spectra, and spectropolarimetry of supernova (SN)
2014ab, obtained through $sim 200$ days after peak brightness. SN 2014ab was a
luminous Type IIn SN ($M_V < -19.14$ mag) discovered after peak brightness near
the nucleus of its host galaxy, VV 306c. Prediscovery upper limits constrain
the time of explosion to within 200 days prior to discovery. While SN 2014ab
declined by $sim 1$ mag over the course of our observations, the observed
spectrum remained remarkably unchanged. Spectra exhibit an asymmetric
emission-line profile with a consistently stronger blueshifted component,
suggesting the presence of dust or a lack of symmetry between the far side and
near side of the SN. The Pa$beta$ emission line shows a profile very similar
to that of H$alpha$, implying that this stronger blueshifted component is
caused either through obscuration by large dust grains, occultation by
optically thick material, or a lack of symmetry between the far side and near
side of the interaction region. Despite these asymmetric line profiles, our
spectropolarimetric data show that SN 2014ab has little detected polarization
after accounting for the interstellar polarization. This suggests that we are
seeing emission from a photosphere that has only small deviation from circular
symmetry face-on. We are likely seeing a SN IIn with nearly circular symmetry
in the plane normal to our line of sight, but with either large-grain dust or
significant asymmetry in the density of circumstellar material or SN ejecta
along our line of sight. We suggest that SN 2014ab and SN 2010jl (as well as
other SNe IIn) may be similar events viewed from different directions.

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