J/ApJ/910/42ivo://CDS.VizieR/J/ApJ/910/42doi:10.26093/cds/vizier.19100042CDSXiang D.Wang X.Lin W.Mo J.Lin H.Burke J.Hiramatsu D.,Hosseinzadeh G.Howell D.A.McCully C.Valenti S.Vinko J.,Wheeler J.C.Ehgamberdiev S.A.Mirzaqulov D.Bodi A.Bognar Z.,Cseh B.Hanyecz O.Ignacz B.Kalup C.Konyves-Toth R.Kriskovics L.,Ordasi A.Pal A.Sarneczky K.Seli B.Szakats R.Arranz-Heras T.,Benavides-Palencia R.Cejudo-Martinez D.De la Fuente-Fernandez P.,Escartin-Perez A.Garcia-de la Cuesta F.Gonzalez-Carballo J.L.,Gonzalez-Farfan R.Limon-Martinez F.Mantero A.Naves-Nogues R.,Morales-Aimar M.Ruiz-Ruiz V.R.Soldan-Alfaro F.C.Valero-Perez J.,Violat-Bordonau F.Zhang T.Zhang J.Li X.Chen Z.Sai H.Li W.2022-09-19T10:16:57Z2022-09-14T14:00:00ZCDS support team

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

cds-question@unistra.frsupernovaeinfrared-photometryvisible-astronomybroad-band-photometryspectroscopyWe present our photometric and spectroscopic observations of the peculiar transient AT2018cow. The multiband photometry covers from peak to ~70days, and the spectroscopy ranges from 5 to ~50days. The rapid rise (t_r_<~2.9days), high luminosity (M_V,peak_~-20.8mag), and fast decline after peak make AT2018cow stand out from any other optical transients, whereas we find that its light curves show a high resemblance to those of Type Ibn supernovae. Moreover, the spectral energy distribution remains at a high temperature of ~14000K at t>15days after discovery. The spectra are featureless in the first 10days, while some broad emission lines due to H, He, C, and O emerge later, with velocity declining from ~14000 to ~3000km/s at the end of our observations. Narrow and weak He I emission lines emerge in the spectra at t>20days after discovery. These emission lines are reminiscent of the features seen in interacting supernovae like the Type Ibn and IIn subclasses. We fit the bolometric light curves with a model of circumstellar interaction and radioactive decay of ^56^Ni and find a good fit with ejecta mass M_ej_~3.16M_{sun}_, circumstellar medium (CSM) mass M_CSM_~0.04M_{sun}_, and ejected ^56^Ni mass M_56Ni_~0.23M_{sun}_. The CSM shell might be formed in an eruptive mass ejection of the progenitor star. Furthermore, the host environment of AT2018cow implies a connection of AT2018cow with massive stars. Combining observational properties and the light-curve fitting results, we conclude that AT2018cow might be a peculiar interacting supernova that originated from a massive star.2021ApJ...910...42Xhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/910/42CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/eso : ESO Science Archive Catalog (ESO, 1991-2022)B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)J/A+A/627/A106 : HI observations of AT 2018cow (Michalowski+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/910/42https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/910/42http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/910/42https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/910/42https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/910/42http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/910/42GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/ApJ/910/42/table1Optical photometric observations of AT2018cowrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD[58285.44/58348.75] Observation date (JD-2400000.5)dtime.epochdoubleomag[13.39/21.37] Observed magnitude in Filtmagphot.magfloate_omag[0.006/0.7]? Uncertainty in omagmagstat.error;phot.magfloatnullableFiltFilter (UBVRIgrio)meta.id;instr.filtercharr_omagTelescope or reference (1)meta.refcharJ/ApJ/910/42/table2Log of optical spectroscopy of AT2018cowInstInstrumentmeta.id;instrcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObs[2018/2019] Year of the observation (UT)stime.epochMJD[58290.58/58743.1] Modified Julian Datedtime.epochdoubleTelTelescope (1)meta.id;instr.telcharlam1[3500/6440] Wavelength lower range in {AA}0.1nmem.wl;stat.minintlam2[6970/10300] Wavelength upper range in {AA}0.1nmem.wl;stat.maxintExp[300/3600] Exposure timestime.duration;obs.exposureintn_MJD[a] Flag on spectrum (2)meta.notecharFileNameName of the ASCII file in subdirectory "sp/"; column added by CDSmeta.id;meta.filecharSpInteractive spectrum Plotmeta.ref.urlchar