J/ApJ/933/L45ivo://CDS.VizieR/J/ApJ/933/L45doi:10.26093/cds/vizier/ba-x5/wefCDSHosseinzadeh G.Sand D.J.Lundqvist P.Andrews J.E.Bostroem K.A.,Dong Y.Janzen D.Jencson J.E.Lundquist M.Meza Retamal N.E.,Pearson J.Valenti S.Wyatt S.Burke J.Howell D.A.McCully C.,Newsome M.Gonzalez E.P.Pellegrino C.Terreran G.Kwok L.A.,Jha S.W.Strader J.Kundu E.Ryder S.D.Haislip J.Kouprianov V.,Reichart D.E.2026-07-02T11:58:44Z2025-04-24T14:38:19ZCDS support team

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

cds-question@unistra.frsupernovaeinfrared-photometryvisible-astronomybroad-band-photometryspectroscopyWe present high-cadence optical and ultraviolet light curves of the normal Type Ia supernova (SN) 2021aefx, which shows an early bump during the first two days of observation. This bump may be a signature of interaction between the exploding white dwarf and a nondegenerate binary companion, or it may be intrinsic to the white dwarf explosion mechanism. In the case of the former, the short duration of the bump implies a relatively compact main-sequence companion star, although this conclusion is viewing-angle dependent. Our best-fit companion-shocking and double-detonation models both overpredict the UV luminosity during the bump, and existing nickel-shell models do not match the strength and timescale of the bump. We also present nebular spectra of SN 2021aefx, which do not show the hydrogen or helium emission expected from a nondegenerate companion, as well as a radio nondetection that rules out all symbiotic progenitor systems and most accretion disk winds. Our analysis places strong but conflicting constraints on the progenitor of SN 2021aefx; no current model can explain all of our observations.2022ApJ...933L..45Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/933/L45CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/659/122 : Improved distances to type Ia supernovae (Jha+, 2007)J/ApJ/745/74 : Pre-maximum spectra of type Ia SNe (Folatelli+, 2012)J/other/Sci/340.170 : Classifications of 188 SNe Ia (Wang+, 2013)J/MNRAS/440/696 : HI absorption in nearby radio galaxies (Allison+, 2014)J/MNRAS/438/L101 : First month on SN 2013ej (Valenti+, 2014)J/MNRAS/459/3939 : Type II supernova light curves (Valenti+, 2016)J/ApJS/235/23 : LEGUS galaxies1 observations (Sabbi+, 2018)J/ApJ/853/62 : Opt. and NIR spectra and LCs of SN2016ija (Tartaglia+, 2018)J/ApJ/870/L1 : K2 obs. of type Ia supernova SN 2018oh (Dimitriadis+, 2019)J/ApJ/870/13 : K2 LC alternative analysis of ASASSN-18bt (Shappee+, 2019)J/A+A/634/A37 : TURTLS Light curves of ^56^Ni distributions (Magee+, 2020)J/ApJ/898/56 : UVOT, ZTF gri LCs & sp. of the SN Ia 2019yvq (Miller+, 2020)J/MNRAS/493/1044 : Nebular spectra of 111 Type Ia supernovae (Tucker+, 2020)J/ApJ/923/L8 : Follow-up phot. & sp. of SNIa 2020hvf (Jiang+, 2021)J/ApJ/922/21 : Type Ia SN 2020nlb opt. photometry & spectra (Sand+, 2021)J/ApJ/914/50 : Opt. phot. and GMOS & NIRES sp. of SN2019yvq (Tucker+, 2021)J/ApJ/914/57 : Opt. & NIR obs. of the SNIa SN2015bp (Wyatt+, 2021)J/ApJ/926/98 : Type Ia supernovae with GALEX observations (Dubay+, 2022)http://www.wis-tns.org/ : Transient Name Server (TNS) homepagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/933/L45https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/933/L45http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/933/L45https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/933/L45https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/933/L45http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/933/L45GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/ApJ/933/L45/fig1Light curve of SN 2021aefxrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD[59529.3/59699.5] Modified Julian Date (JD-2400000.5)dtime.epochdoubleFiltFilter (1)meta.id;instr.filtercharl_omagLimit flag on omagmeta.code.errorcharomag[11.69/20.42] Apparent Magnitude in Filtermagphot.magfloate_omag[0/0.31]? Uncertainty in omagmagstat.error;phot.magfloatnullableTelTelescope (2)meta.id;instr.telcharJ/ApJ/933/L45/table1Log of spectroscopic observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD[59529.8/59681.4] Modified Julian Datedtime.epochdoubleTelTelescope (1)meta.id;instr.telcharInstInstrumentmeta.id;instrcharPhase[-16.6/134.2] Phasedtime.phasefloatf_PhaseFlag on Phase (2)meta.codecharFileNameName of the FITS file in subdirectory "sp"; column added by CDSmeta.id;meta.fitscharspInteractive spectrum plotmeta.ref.urlcharfitsDownload the FITS filemeta.ref.urlchar