The Type II superluminous SN 2008es at late times: near-infrared excess and circumstellar interaction
Author
Bhirombhakdi, KornpobChornock, Ryan
Miller, Adam A
Filippenko, Alexei V
Cenko, S Bradley
Smith, Nathan
Affiliation
Univ Arizona, Steward ObservIssue Date
2019-07-25
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OXFORD UNIV PRESSCitation
Kornpob 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/stz1928Rights
Copyright © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
SN 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.ISSN
0035-8711Version
Final published versionSponsors
National 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)ae974a485f413a2113503eed53cd6c53
10.1093/mnras/stz1928