J/ApJ/895/49ivo://CDS.VizieR/J/ApJ/895/49doi:10.26093/cds/vizier.18950049CDSHo A.Y.Q.Perley D.A.Kulkarni S.R.Dong D.Z.J.De K.Chandra P.,Andreoni I.Bellm E.C.Burdge K.B.Coughlin M.Dekany R.Feeney M.,Frederiks D.D.Fremling C.Golkhou V.Z.Graham M.J.Hale D.Helou G.,Horesh A.Kasliwal M.M.Laher R.R.Masci F.J.Miller A.A.Porter M.,Ridnaia A.Rusholme B.Shupe D.L.Soumagnac M.T.Svinkin D.S.2022-03-16T12:26:26Z2021-10-06T08:21:16ZCDS support team

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

cds-question@unistra.frgalaxiesvisible-astronomyspectroscopyWe present ZTF18abvkwla (the "Koala"), a fast blue optical transient discovered in the Zwicky Transient Facility (ZTF) One-Day Cadence (1DC) Survey. ZTF18abvkwla has a number of features in common with the groundbreaking transient AT2018cow: blue colors at peak (g-r~-0.5mag), a short rise time from half-max of under two days, a decay time to half-max of only three days, a high optical luminosity (M_g.peak_~-20.6mag), a hot (>~40000K) featureless spectrum at peak light, and a luminous radio counterpart. At late times ({Delta}>80days), the radio luminosity of ZTF18abvkwla ({nu}L_{nu}_>~10^40^erg/s at 10GHz, observer-frame) is most similar to that of long-duration gamma-ray bursts (GRBs). The host galaxy is a dwarf starburst galaxy (M~5x10^8^M{odot}, SFR~7M{odot}/yr) that is moderately metal-enriched (log[O/H]~8.5), similar to the hosts of GRBs and superluminous supernovae. As in AT2018cow, the radio and optical emission in ZTF18abvkwla likely arise from two separate components: the radio from fast- moving ejecta ({Gamma}{beta}c>0.38c) and the optical from shock-interaction with confined dense material (<0.07M{sun} in ~10^15^cm). Compiling transients in the literature with t_rise_<5days and M_peak_<-20mag, we find that a significant number are engine-powered, and suggest that the high peak optical luminosity is directly related to the presence of this engine. From 18 months of the 1DC survey, we find that transients in this rise-luminosity phase space are at least two to three orders of magnitude less common than CC SNe. Finally, we discuss strategies for identifying such events with future facilities like the Large Synoptic Survey Telescope, as well as prospects for detecting accompanying X-ray and radio emission.2020ApJ...895...49Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/895/49CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/720/1513 : The afterglows of Swift-era GRBs. I. (Kann+, 2010)J/other/Nat/463.513 : Radio observations of SN 2009bb (Soderberg+, 2010)J/ApJ/759/107 : Core-collapse SNe and host galaxies (Kelly+, 2012)J/ApJ/794/23 : Pan-STARRS1 transients optical photometry (Drout+, 2014)J/ApJ/781/37 : Multi-band photometry of GRB 130427A (Perley+, 2014)J/ApJS/211/13 : The second Fermi/GBM GRB catalog (4yr) (von Kienlin+, 2014)J/A+A/581/A125 : UV/Optical/NIR spectroscopy GRB hosts (Kruehler+, 2015)J/ApJ/819/35 : Light curves of four transients from PTF & SNLS (Arcavi+,2016)J/ApJ/830/13 : Host-galaxy NUV-NIR data 32 superluminous SNe (Perley+, 2016)J/ApJ/851/107 : iPTF 16asu photometry follow-up (Whitesides+, 2017)J/A+A/617/A122 : GRB 111209A GROND and UVOT light curves (Kann+, 2018)J/ApJ/887/169 : UV-Opt light curves of the type Ic SN 2018gep (Ho+, 2019)J/ApJ/886/152 : ZTF early observations of Type Ia SNe. I. LCs (Yao+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/895/49https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/895/49http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/895/49https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/895/49https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/895/49http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/895/49GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/895/49/fig5Spectrum of ZTF18abvkwla at the peak of the g-band optical light curverecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWave[3400/10501] Observed wavelength; Angstroms0.1nmem.wldoubleFlux[-4.6e-17/3.9e-16] Observed flux; erg/s/cm^2^/AcW.m**-2.nm**-1phot.fluxdoubleJ/ApJ/895/49/fig6Spectrum of the host galaxy of ZTF18abvkwlarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWave[3070/10308] Observed wavelength; Angstroms0.1nmem.wldoubleFlux[-6.6e-17/5.7e-16] Observed flux; erg/s/cm^2^/AcW.m**-2.nm**-1phot.fluxdoublee_Flux[1.4e-18/1.1e-16] Uncertainty in FluxcW.m**-2.nm**-1stat.error;phot.fluxdouble