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Published November 1, 2019 | Version Submitted + Published
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SN2018kzr: a rapidly declining transient from the destruction of a white dwarf

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Abstract

We present SN2018kzr, the fastest declining supernova-like transient, second only to the kilonova, AT2017gfo. SN2018kzr is characterized by a peak magnitude of M_r = −17.98, a peak bolometric luminosity of ~1.4 × 10⁴³ erg s⁻¹, and a rapid decline rate of 0.48 ± 0.03 mag day⁻¹ in the r band. The bolometric luminosity evolves too quickly to be explained by pure ⁵⁶Ni heating, necessitating the inclusion of an alternative powering source. Incorporating the spin-down of a magnetized neutron star adequately describes the lightcurve and we estimate a small ejecta mass of M_(ej) = 0.10 ± 0.05 M⊙. Our spectral modeling suggests the ejecta is composed of intermediate mass elements including O, Si, and Mg and trace amounts of Fe-peak elements, which disfavors a binary neutron star merger. We discuss three explosion scenarios for SN2018kzr, given the low ejecta mass, intermediate mass element composition, and high likelihood of additional powering—the core collapse of an ultra-stripped progenitor, the accretion induced collapse (AIC) of a white dwarf, and the merger of a white dwarf and neutron star. The requirement for an alternative input energy source favors either the AIC with magnetar powering or a white dwarf–neutron star merger with energy from disk wind shocks.

Additional Information

© 2019 The American Astronomical Society. Received 2019 September 6; revised 2019 October 7; accepted 2019 October 15; published 2019 October 31. Based in part on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile as part of the extended Public ESO Spectroscopic Survey for Transient Objects (ePESSTO), program 199.D-0143, the SALT Large Science Programme on transients (2018-2-LSP-001), MNiSW DIR/WK/2016/07, GROND support through DFG grant HA 1850/28-1. ATLAS is supported primarily through NASA grant NN12AR55G, 80NSSC18K1575. This research made use of TARDIS supported by the Google Summer of Code, ESA's Summer of Code in Space program. Funding acknowledgments: STFC ST/P000312/1 (SJS, SAS); Alexander von Humboldt Foundation (TWC); ERC and H2020 MSC grants [615929, 725161, 758638] (A.G.Y., C.P.G., K.M., and L.G.); ISF GW excellence center, IMOS, BSF Transformative program, Benoziyo Endowment Fund for the Advancement of Science, Deloro Institute, Veronika A. Rabl Physics Discretionary Fund, Paul and Tina Gardner and the WIS-CIT, Helen and Martin Kimmel Award (AGY); RAS Research Fellowship (MN), Polish NCN MAESTRO grant 2014/14/A/ST9/00121 (MG), IC120009 "Millennium Institute of Astrophysics" of the Iniciativa Científica Milenio del Ministerio Economía, Fomento y Turismo de Chile and CONICYT PAI/INDUSTRIA 79090016 (OR); NRF South Africa (DAHB) lasair is supported by STFC grants ST/N002512/1 and ST/N002520/1. Facilities: ESO (NTT - , VLT) - , Gemini (GMOS) - , Keck (LRIS) - , SALT (RSS) - , Swift (XRT and UVOT) - , SALT - , - Max Planck:2.2m, ATLAS - , ZTF - , Liverpool:2m (IO:O) - , LCO. -

Attached Files

Published - McBrien_2019_ApJL_885_L23.pdf

Submitted - 1909.04545.pdf

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Additional details

Identifiers

Eprint ID
99120
Resolver ID
CaltechAUTHORS:20191007-140649649

Related works

Describes
https://arxiv.org/abs/1909.04545 (URL)

Funding

Deutsche Forschungsgemeinschaft (DFG)
HA 1850/28-1
NASA
NN12AR55G
NASA
80NSSC18K1575
Google
European Space Agency (ESA)
Science and Technology Facilities Council (STFC)
ST/P000312/1
Alexander von Humboldt Foundation
European Research Council (ERC)
615929
European Research Council (ERC)
725161
European Research Council (ERC)
758638
Israel Science Foundation
Ministry of Science (Israel)
Binational Science Foundation (USA-Israel)
Benoziyo Endowment Fund
Deloro Institute
Veronika A. Rabl Physics Discretionary Fund
Paul and Tina Gardner
Helen and Martin Kimmel Award
Russian Academy of Sciences
National Science Centre (Poland)
2014/14/A/ST9/00121
Iniciativa Científica Milenio del Ministerio de Economía, Fomento y Turismo
IC120009
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)
79090016
National Research Foundation (South Africa)
Science and Technology Facilities Council (STFC)
ST/N002512/1
Science and Technology Facilities Council (STFC)
ST/N002520/1

Dates

Created
2019-10-07
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Updated
2021-11-16
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Caltech groups
Zwicky Transient Facility, Astronomy Department, Division of Geological and Planetary Sciences (GPS)