DES16C3cje: A low-luminosity, long-lived supernova

We present DES16C3cje, a low-luminosity, long-lived type II supernova (SN II) at redshift 0.0618, detected by the Dark Energy Survey (DES). DES16C3cje is a unique SN. The spectra are characterized by extremely narrow photospheric lines corresponding to very low expansion velocities of . 1500 km s−1 , and the light curve shows an initial peak that fades after 50 days before slowly rebrightening over a further 100 days to reach an absolute brightness of M푟 ∼ −15.5 mag. The decline rate of the late-time light curve is then slower than that expected from the powering by radioactive decay of 56Co, but is comparable to that expected from accretion power. Comparing the bolometric light curve with hydrodynamical models, we find that DES16C3cje can be explained by either i) a low explosion energy (0.11 foe) and relatively large 56Ni production of 0.075 M from a ∼ 15 M red supergiant progenitor typical of other SNe II, or ii) a relatively compact ∼ 40 M star, explosion energy of 1 foe, and 0.08 M of 56Ni. Both scenarios require additional energy input to explain the late-time light curve, which is consistent with fallback accretion at a rate of ∼ 0.5 × 10−8 M s−1.
EU/FP7-ERC grant 615929
European Union (EU) 839090
Alexander von Humboldt Foundation
Science Foundation Ireland
Polish NCN MAESTRO 2014/14/A/ST9/00121
Royal Astronomical Society Research Fellowship
European Organisation for Astronomical Research in the Southern Hemisphere, Chile 299.D-5040(A) 299.D-5040(B) 0100.D-0461(A) 194.C-0207(I)
PESSTO, (the Public ESO Spectroscopic Survey for Transient Objects Survey) ESO program 197.D1075 199.D-0143
Programme NOAO GS-2016B-Q-9
United States Department of Energy (DOE)
National Science Foundation (NSF)
Spanish Government
Science & Technology Facilities Council (STFC)
Higher Education Funding Council for England
National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign
Kavli Institute of Cosmological Physics at the University of Chicago
Ohio State University
Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University
Ciencia Tecnologia e Inovacao (FINEP)
Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro
National Council for Scientific and Technological Development (CNPq)
Ministerio da Ciencia, Tecnologia e Inovacao
German Research Foundation (DFG)
Collaborating Institutions in the Dark Energy Survey
United States Department of Energy (DOE) University of Chicago
University of California at Santa Cruz
University of Cambridge
Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas-Madrid
University of Chicago
University College London
DES-Brazil Consortium
University of Edinburgh
ETH Zurich
University of Illinois at Urbana-Champaign
Institut de Ciencies de l'Espai (IEEC/CSIC)
Institut de Fisica d'Altes Energies
Ludwig-Maximilians Universitat Munchen and the associated Excellence Cluster Universe
University of Michigan System
National Science Foundation (NSF) NSF - Directorate for Mathematical & Physical Sciences (MPS)
University of Nottingham
University of Pennsylvania
University of Portsmouth
Stanford University United States Department of Energy (DOE)
Stanford University
University of Sussex
Texas AM University
OzDES Membership Consortium
German Research Foundation (DFG) HA 1850/28-1
European Union (EU) PGC2018-095317-B-C21
National Science Foundation (NSF) AST-1138766 AST-1536171
MINECO AYA2015-71825 ESP2015-66861 FPA2015-68048 SEV-2016-0588 SEV2016-0597 MDM-2015-0509
ERDF funds from the European Union
CERCA program of the Generalitat de Catalunya
European Research Council under the European Union's Seventh Framework Program (FP7/2007-2013)
European Research Council (ERC) 240672 291329 306478
National Council for Scientific and Technological Development (CNPq) 465376/2014-2
National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility DE-AC02-05CH11231
United States Department of Energy (DOE) DE-AC02-07CH11359