The Type II superluminous SN 2008es at late times: near-infrared excess and circumstellar interaction
Miller, Adam A
Filippenko, Alexei V
Cenko, S Bradley
AffiliationUniv Arizona, Steward Observ
MetadataShow full item record
PublisherOXFORD UNIV PRESS
CitationKornpob Bhirombhakdi, Ryan Chornock, Adam A Miller, Alexei V Filippenko, S Bradley Cenko, Nathan Smith, The Type II superluminous SN 2008es at late times: near-infrared excess and circumstellar interaction, Monthly Notices of the Royal Astronomical Society, Volume 488, Issue 3, September 2019, Pages 3783–3793, https://doi.org/10.1093/mnras/stz1928
RightsCopyright © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
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AbstractSN 2008es is one of the rare cases of a Type II superluminous supernova (SLSN), showing no narrow features in its early-time spectra, and therefore, its powering mechanism is under debate between circumstellar interaction (CSI) and magnetar spin-down. Late-time data are required for better constraints. We present optical and near-infrared (NIR) photometry obtained from Gemini, Keck, and Palomar Observatories from 192 to 554 d after explosion. Only broad H α emission is detected in a Gemini spectrum at 288 d. The line profile exhibits red-wing attenuation relative to the early-time spectrum. In addition to the cooling SN photosphere, an NIR excess with blackbody temperature ∼1500 K and radius ∼1016 cm is observed. This evidence supports dust condensation in the cool dense shell being responsible for the spectral evolution and NIR excess. We favour CSI, with ∼2–3 M⊙ of circumstellar material (CSM) and ∼10–20 M⊙ of ejecta, as the powering mechanism, which still dominates at our late-time epochs. Both models of uniform density and steady wind fit the data equally well, with an effective CSM radius ∼1015 cm, supporting the efficient conversion of shock energy to radiation by CSI. A low amount (≲0.4 M⊙) of 56Ni is possible but cannot be verified yet, since the light curve is dominated by CSI. The magnetar spin-down powering mechanism cannot be ruled out, but is less favoured because it overpredicts the late-time fluxes and may be inconsistent with the presence of dust.
VersionFinal published version
SponsorsNational Aeronautics and Space Administration (NASA)National Aeronautics & Space Administration (NASA) [80NSSC18K0665]; NSFNational Science Foundation (NSF) [PHY-1607611]; TABASGO Foundation; Christopher R. Redlich Fund; Miller Institute for Basic Research in Science (U.C. Berkeley); NSF (United States)National Science Foundation (NSF) [GN-2009A-Q-48]; National Research Council (Canada) [GN-2009A-Q-48]; CONICYT (Chile)Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) [GN-2009A-Q-48]; Ministerio de Ciencia, Tecnologia e Innovacion Productiva (Argentina) [GN-2009A-Q-48]; Ministerio da Ciencia, Tecnologia e Inovacao (Brazil) [GN-2009A-Q-48]; W. M. Keck FoundationW.M. Keck Foundation; NASANational Aeronautics & Space Administration (NASA)