J/ApJ/887/169ivo://CDS.VizieR/J/ApJ/887/169doi:10.26093/cds/vizier.18870169CDSHo A.Y.Q.Goldstein D.A.Schulze S.Khatami D.K.Perley D.A.Ergon M.,Gal-Yam A.Corsi A.Andreoni I.Barbarino C.Bellm E.C.,Blagorodnova N.Bright J.S.Burns E.Cenko S.B.Cunningham V.De K.,Dekany R.Dugas A.Fender R.P.Fransson C.Fremling C.Goldstein A.,Graham M.J.Hale D.Horesh A.Hung T.Kasliwal M.M.Kuin N.P. M,Kulkarni S.R.Kupfer T.Lunnan R.Masci F.J.Ngeow C.-C.Nugent P.E.,Ofek E.O.Patterson M.T.Petitpas G.Rusholme B.Sai H.Sfaradi I.,Shupe D.L.Sollerman J.Soumagnac M.T.Tachibana Y.Taddia F.,Walters R.Wang X.Yao Y.Zhang X.2022-07-06T06:26:41Z2021-06-22T16:42:23ZCDS support team

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

cds-question@unistra.frsupernovaeultraviolet-photometryinfrared-photometryvisible-astronomyWide-band photometryeffective-temperatureWe present detailed observations of ZTF18abukavn (SN2018gep), discovered in high-cadence data from the Zwicky Transient Facility as a rapidly rising (1.4+/-0.1mag/hr) and luminous (M_g,peak_=-20mag) transient. It is spectroscopically classified as a broad-lined stripped-envelope supernova (Ic-BL SN). The high peak luminosity (L_bol>~3x10^44^erg/s), the short rise time (t_rise_=3days in g band), and the blue colors at peak (g-r~-0.4) all resemble the high-redshift Ic-BL iPTF16asu, as well as several other unclassified fast transients. The early discovery of SN2018gep (within an hour of shock breakout) enabled an intensive spectroscopic campaign, including the highest-temperature (T_eff_>~40000K) spectra of a stripped-envelope SN. A retrospective search revealed luminous (M_g_~M_r_~-14mag) emission in the days to weeks before explosion, the first definitive detection of precursor emission for a Ic-BL. We find a limit on the isotropic gamma-ray energy release E_{gamma,iso}_<4.9x10^48^erg, a limit on X-ray emission L_X_<10^40^erg/s, and a limit on radio emission {nu}L_{nu}_<~10^37^erg/s. Taken together, we find that the early (<10days) data are best explained by shock breakout in a massive shell of dense circumstellar material (0.02M_{sun}_) at large radii (3x10^14^cm) that was ejected in eruptive pre-explosion mass-loss episodes. The late-time (>10days) light curve requires an additional energy source, which could be the radioactive decay of Ni-56.2019ApJ...887..169Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/887/169CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)II/317 : The CFHTLS Survey (T0007 release) (Hudelot+ 2012)V/139 : The SDSS Photometric Catalog, Release 9 (Adelman- McCarthy+, 2012)J/A+A/448/955 : Abundances of em. galaxies in SDSS-DR3 (Izotov+, 2006)J/MNRAS/397/1177 : Swift-XRT observations of GRBs (Evans+, 2009)J/ApJ/702/226 : Swift/UVOT panchromatic obs. of SN 2008D (Modjaz+, 2009)J/other/Nat/463.513 : Radio observations of SN 2009bb (Soderberg+, 2010)J/ApJ/760/L33 : Photometry of the Ic supernova PTF12gzk (Ben-Ami+, 2012)J/MNRAS/421/3027 : Statisical study of galaxy dust emissions (Bourne+, 2012)J/ApJ/747/L5 : R-band observations of PTF 10vgv (Corsi+, 2012)J/A+A/558/A131 : Model spectra of hot stars at pre-SN stage (Groh+, 2013)J/A+A/559/A114 : Updated O3N2 and N2 abundance indicators (Marino+, 2013)J/MNRAS/429/3330 : AMI Galactic Plane Survey at 16GHz. I. (Perrott+, 2013)J/ApJ/782/42 : Panchromatic observations of PTF11qcj (Corsi+, 2014)J/ApJ/794/23 : Pan-STARRS1 transients optical photometry (Drout+, 2014)J/ApJS/211/13 : 2nd Fermi/GBM GRB catalog (4yr) (von Kienlin+, 2014)J/A+A/573/A12 : SN1993J sp. 100-500d post-explosion (Jerkstrand+, 2015)J/A+A/581/A125 : UV/Optical/NIR spectroscopy GRB hosts (Kruehler+, 2015)J/ApJ/819/35 : LCs of four transients from PTF & SNLS (Arcavi+, 2016)J/A+A/593/A68 : PTF12os & iPTF13bvn spectra and LCs (Fremling+, 2016)J/ApJ/832/108 : Spectral data of Type Ic & Ic-bl SNe (Modjaz+, 2016)J/ApJ/836/5 : Abundances of LAMOST giants from APOGEE DR12 (Ho+, 2017)J/ApJ/851/107 : iPTF 16asu photometry follow-up (Whitesides+, 2017)J/other/Sci/362.201 : iPTF 14gqr (SN 2014ft) photometry (De+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/887/169https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/887/169http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/887/169https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/887/169https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/887/169http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/887/169GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapUVOpticalInfrareddefaultJ/ApJ/887/169/table3Physical evolution of AT2018gep from blackbody fitsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD[58370.2/58407.85] Modified Julian Date (JD-2400000.5)dtime.epochdoubledt[0.05/37.7] Time from explosion, daysdtime.intervalfloatRph[20/304] Black-body (photospheric) radius1e+15cmphys.size.radiusfloate_Rph[4.9/86] Lower uncertainty on Rph1e+15cmstat.errorfloatE_Rph[7.8/96] Upper uncertainty on Rph1e+15cmstat.error;stat.maxfloatTeff[4.2/46.5] Black-body effective temperatureKphys.temperature.effectivefloate_Teff[0.3/14] Lower uncertainty on TeffKstat.error;phys.temperature.effectivefloatE_Teff[0.3/16.1] Upper uncertainty on TeffKstat.error;stat.maxfloatLbol[335700000/74270000000] Bolometric Luminosity1e-07Wphys.luminositydoublee_LbolLower uncertainty on Lbol1e-07Wstat.errordoubleE_Lbol[115400000/85580000000] Upper uncertainty on Lbol1e-07Wstat.error;stat.maxdoublechi2[0/5.53] Reduced {chi}^2^stat.fit.chi2floatdof[0/8] Fit degrees of freedomstat.fit.dof;stat.fit.param;meta.modelledintJ/ApJ/887/169/table5Optical and ultraviolet photometry for SN2018geprecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJD[2458370.6/2458429.6] Julian date of observationdtime.epochdoubledt[0.02/59] Elapsed time for transientdtime.intervalfloatTelTelescope/Instrument used (1)instr.setupcharFiltFilter usedinstr.setup;instr.filtercharomag[15.19/26.7]? Observed AB magnitude in Filtmagphot.magfloatnullablee_omag[0.01/76.3] Uncertainty in omagmagstat.error;phot.magfloat