An optical and near-infrared study of the Type Ia/IIn Supernova PS15si
AuthorKilpatrick, Charles D.
Andrews, Jennifer E.
Milne, P. A.
Rieke, George H.
Filippenko, Alexei V.
AffiliationUniv Arizona, Steward Observ
MetadataShow full item record
PublisherOXFORD UNIV PRESS
CitationAn optical and near-infrared study of the Type Ia/IIn Supernova PS15si 2016, 463 (1):1088 Monthly Notices of the Royal Astronomical Society
Rights© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
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AbstractWe present optical/near-infrared spectroscopy and photometry of the supernova (SN) PS15si. This object was originally identified as a Type IIn SN, but here we argue that it should be reclassified as a Type Ia SN with narrow hydrogen lines originating from interaction with circumstellar matter (CSM; i.e. SN Ia/IIn or SN Ia-CSM). Based on deep non-detections 27 d before discovery, we infer that this SN was discovered around or slightly before optical maximum, and we estimate the approximate time that it reached R-band maximum based on comparison with other SNe Ia/IIn. In terms of spectral morphology, we find that PS15si can be matched to a range of SN Ia spectral types, although SN 1991T-like SNe Ia provides the most self-consistent match. While this spectral classification agrees with analysis of most other SNe Ia/IIn, we find that the implied CSM-interaction luminosity is too low. We infer that the similarity between PS15si and the hot, overluminous, high-ionization spectrum of SN 1991T is a consequence of a spectrum that originates in ejecta layers that are heated by ultraviolet/X-ray radiation from CSM interaction. In addition, PS15si may have rebrightened over a short time-scale in the B and V bands around 85 d after discovery, perhaps indicating that the SN ejecta are interacting with a local enhancement in CSM produced by clumps or a shell at large radii.
VersionFinal published version
SponsorsW. M. Keck Foundation; ESO programmes [188.D-3003, 191.D-0935]; NASA [NNX12AR65G, NNX14AM74G]; NASA by JPL/Caltech ; NSF [AST-1312221, AST-1515559, AST-1211916]; Gary & Cynthia Bengier; Richard & Rhoda Goldman Fund; Christopher R. Redlich Fund; TABASGO Foundation