J/ApJ/922/247ivo://CDS.VizieR/J/ApJ/922/247doi:10.26093/cds/vizier.19220247CDSOfek E.O.Adams S.M.Waxman E.Sharon A.Kushnir D.Horesh A.Ho A.,Kasliwal M.M.Yaron O.Gal-Yam A.Kulkarni S.R.Bellm E.Masci F.,Shupe D.Dekany R.Graham M.Riddle R.Duev D.Andreoni I.,Mahabal A.Drake A.2023-07-03T13:25:42Z2023-05-03T09:40:44ZCDS support team

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

cds-question@unistra.frtransient-sourcesphotometryvisible-astronomyWe report on the discovery of AT 2018lqh (ZTF 18abfzgpl)-a rapidly evolving extragalactic transient in a star-forming host at 242Mpc. The transient g-band light curve's duration above a half-maximum light is about 2.1 days, where 0.4/1.7 days are spent on the rise/decay, respectively. The estimated bolometric light curve of this object peaked at about 7x10^42^erg/s --roughly 7 times brighter than the neutron star (NS)-- NS merger event AT 2017gfo. We show that this event can be explained by an explosion with a fast (v~0.08c) low-mass (~0.07M_{sun}_) ejecta, composed mostly of radioactive elements. For example, ejecta dominated by ^56^Ni with a timescale of t_0_~1.6d for the ejecta to become optically thin for {gamma}-rays fits the data well. Such a scenario requires burning at densities that are typically found in the envelopes of neutron stars or the cores of white dwarfs. A combination of circumstellar material (CSM) interaction power at early times and shock cooling at late times is consistent with the photometric observations, but the observed spectrum of the event may pose some challenges for this scenario. We argue that the observations are not consistent with a shock breakout from a stellar envelope, while a model involving a low-mass ejecta ramming into low-mass CSM cannot explain both the early- and late-time observations.2021ApJ...922..247Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/922/247CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/763/42 : X-ray emission from 28 SNe (IIn, Ibn or SLSN-I) (Ofek+, 2013)J/ApJ/768/47 : Swift/XRT 0.2-10keV observations of SN2009ip (Ofek+, 2013)J/other/Nat/494.65 : SN 2010mc outburst before explosion (Ofek+, 2013)J/ApJ/794/23 : Pan-STARRS1 transients optical photometry (Drout+, 2014)J/ApJ/788/154 : Palomar Transient Factory SNe IIn photometry (Ofek+, 2014)J/ApJ/789/104 : SNe IIn observations and properties (Ofek+, 2014)J/ApJ/781/42 : Optical photometry of SN 2010jl (Ofek+, 2014)J/ApJ/819/35 : Light curves of 4 transients from PTF & SNLS (Arcavi+, 2016)J/MNRAS/481/894 : Rapidly evolving transients in the DES (Pursiainen+, 2018)J/A+A/631/A147 : Transient processing and analysis using AMPEL (Nordin+, 2019)J/ApJ/912/46 : ZTF Type II supernovae with follow-up obs. (Bruch+, 2021)J/ApJ/907/99 : Pre-explosion light curve of 227 SNe (Strotjohann+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/922/247https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/922/247http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/922/247https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/922/247https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/922/247http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/922/247GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/922/247/table1ZTF photometric measurements of AT 2018lqhrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJD[8222.9/8569.1] Julian Date; JD-2450000dtime.epochdoubleBand[1/3] Bandpass used in observation (1)meta.code;instr.filterintCount[-336/279] Counts in subtracted imagectphot.countfloate_Count[15/180] Error in Countctstat.error;phot.countfloatZP[25.66/26.33] Photometric zero point; AB magmagphot.mag;arith.zpfloatmag[20.21/30.04] Apparent AB magnitude Band; sinh-mag/Luptitudesmagphot.magfloatS/N[0/13.7] Signal-to-Noise of measurementsstat.snrfloat