J/ApJ/913/143ivo://CDS.VizieR/J/ApJ/913/143doi:10.26093/cds/vizier.19130143CDSGomez S.Berger E.Hosseinzadeh G.Blanchard P.K.Nicholl M.,Villar V.A.2023-10-06T10:39:41Z2022-12-15T15:26:10ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frsupernovaeinfrared-photometryvisible-astronomybroad-band-photometryWe present optical photometry and spectroscopy of SN 2019stc (=ZTF19acbonaa), an unusual Type Ic supernova (SN Ic) at a redshift of z=0.117. SN 2019stc exhibits a broad double-peaked light curve, with the first peak having an absolute magnitude of M_r_=-20.0mag, and the second peak, about 80 rest-frame days later, M_r_=-19.2mag. The total radiated energy is large, E_rad_~2.5x10^50^erg. Despite its large luminosity, approaching those of Type I superluminous supernovae (SLSNe), SN 2019stc exhibits a typical SN Ic spectrum, bridging the gap between SLSNe and SNe Ic. The spectra indicate the presence of Fe-peak elements, but modeling of the first light-curve peak with radioactive heating alone leads to an unusually high nickel mass fraction of f_Ni_~0.31 (M_Ni_~3.2M_{sun}_). Instead, if we model the first peak with a combined magnetar spin-down and radioactive heating model we find a better match with M_ej_~4M_{sun}_, a magnetar spin period of P_spin_~7.2ms, and magnetic field of B~10^14^G, and f_Ni_<~0.2 (consistent with SNe Ic). The prominent second peak cannot be naturally accommodated with radioactive heating or magnetar spin-down, but instead can be explained as circumstellar interaction with ~0.7M_{sun}_ of hydrogen-free material located ~400au from the progenitor. Accounting for the ejecta mass, circumstellar shell mass, and remnant neutron star mass, we infer a CO core mass prior to explosion of ~6.5M_{sun}_. The host galaxy has a metallicity of ~0.26Z_{sun}_, low for SNe Ic but consistent with SLSNe. Overall, we find that SN 2019stc is a transition object between normal SNe Ic and SLSNe.2021ApJ...913..143Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/913/143CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/741/97 : Light curves of Ibc supernovae (Drout+, 2011)J/AJ/147/99 : Spectroscopy of 73 stripped core-collapse SNe (Modjaz+, 2014)J/A+A/618/A37 : Spectral log of (i)PTF stripped-envelope SN (Fremling+, 2018)J/ApJ/881/87 : 9 epochs spectroscopy of type I SN 201iet (Gomez+, 2019)J/ApJ/887/169 : UV-Opt light curves of the type Ic SN 2018gep (Ho+, 2019)J/ApJ/901/61 : LCs of 4 superluminous SNe from the ZTF survey (Lunnan+, 2020)J/ApJ/902/L8 : Optical & NIR spectra of ZTF19aawfbtg (SN2019hge) (Yan+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/913/143https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/913/143http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/913/143https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/913/143https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/913/143http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/913/143GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/ApJ/913/143/fig2Optical light curves of SN 2019stc in the griz bandsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD[58745.49/59174.5] Modified Julian Date of observation (JD-2400000.5)dtime.epochdoublel_omagUpper limit flag on omagmeta.code.errorcharomag[18.69/25.77] Observed AB magnitude in Filtmagphot.magdoublee_omag[0.02/0.6]? Uncertainty in omagmagstat.error;phot.magdoublenullableFiltFilter (g, r, i or z)meta.id;instr.filtercharTelTelescope/Instrument used (1)instr.setupcharSystPhotometric System (always "AB")meta.notechar