J/ApJ/943/L20ivo://CDS.VizieR/J/ApJ/943/L20doi:10.26093/cds/vizier.19439020CDSSrivastav S.Smartt S.J.Huber M.E.Dimitriadis G.Chambers K.C.,Fulton M.D.Moore T.Callan F.P.Gillanders J.H.Maguire K.,Nicholl M.Shingles L.J.Sim S.A.Smith K.W.Anderson J.P.,de Boer T.Chen T.-W.Gao H.Young D.R.2025-05-21T20:14:41Z2025-02-12T09:29:49ZCDS support team

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

cds-question@unistra.frsupernovaephotometryvisible-astronomyspectroscopyWe present observations and analysis of the hostless and luminous Type Ia supernova 2022ilv, illustrating it is part of the 2003fg-like family, often referred to as super-Chandrasekhar (Ia-SC) explosions. The Asteroid Terrestrial-impact Last Alert System light curve shows evidence of a short-lived, pulse-like early excess, similar to that detected in another luminous Type Ia supernova (SN 2020hvf). The light curve is broad, and the early spectra are remarkably similar to those of SN 2009dc. Adopting a redshift of z=0.026+/-0.005 for SN 2022ilv based on spectral matching, our model light curve requires a large ^56^Ni mass in the range 0.7-1.5M_{sun}_ and a large ejecta mass in the range 1.6-2.3M_{sun}_. The early excess can be explained by fast-moving SN ejecta interacting with a thin, dense shell of circumstellar material close to the progenitor (~10^13^cm) a few hours after the explosion. This may be realized in a double-degenerate scenario, wherein a white dwarf merger is preceded by the ejection of a small amount (~10^-3^-10^-2^M_{sun}_) of hydrogen and helium-poor tidally stripped material. A deep pre-explosion Pan-STARRS1 stack indicates no host galaxy to a limiting magnitude of r~24.5. This implies a surprisingly faint limit for any host of M_r_>~-11, providing further evidence that these types of explosions occur predominantly in low-metallicity environments.2023ApJ...943L..20Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/943/L20CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/sn : Asiago Supernova Catalogue (Barbon et al., 1999-)J/AJ/130/873 : BQS objects in the SDSS DR3 area (Jester+, 2005)J/MNRAS/383/1485 : BVRI light curves of SN 2003jd (Valenti+, 2008)J/AJ/137/4517 : UVOT light curves of supernovae (Brown+, 2009)J/MNRAS/410/585 : SN 2009dc BVRI light curves (Silverman+, 2011)J/MNRAS/446/3895 : The rising light curves of Type Ia supernovae (Firth+, 2015)J/ApJS/218/10 : HET Massive Galaxy Survey (HETMGS) (van den Bosch+, 2015)J/ApJ/867/105 : ATLAS all-sky stellar ref. cat. ATLAS-REFCAT2 (Tonry+, 2018)J/ApJ/870/13 : K2 LC alternative analysis of ASASSN-18bt (Shappee+, 2019)J/ApJ/900/140 : CSP-II: sp. obs. of LSQ14fmg (Hsiao+, 2020)J/A+A/634/A37 : TURTLS Light curves of ^56^Ni distributions (Magee+, 2020)J/ApJ/923/L8 : Follow-up phot. & sp. of SNIa 2020hvf (Jiang+, 2021)J/ApJ/927/78 : Follow-up of type Ia SN2020esm (Dimitriadis+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/943/L20https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/943/L20http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/943/L20https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/943/L20https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/943/L20http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/943/L20GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/943/L20/table1The photometric observations of SN 2022ilv and SN 2020hvfInstInstrument (1)meta.id;instrcharFiltFiltermeta.id;instr.filtercharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSNSupernova identifiermeta.id;meta.maincharMJD[58960.39/59818.99] Modified Julian Datedtime.epochdoublel_magLimit flag on magmeta.code.errorcharmag[12.59/20.62] Apparent magnitude in Filtermagphot.magfloate_mag[0/0.5]? Uncertainty in magmagstat.error;phot.magfloatnullableJ/ApJ/943/L20/spectraSummary of LT/SPRAT spectra; table added by CDSrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSNSupernova identifiermeta.id;meta.maincharDateObservation datestime.epoch;obsnullableInstTelescope / Instrument ("LT/SPRAT")instrcharFileNameName of the file in subdirectory "sp"meta.id;meta.filecharfitsDownload the FITS filemeta.ref.urlcharspInteractive spectrum plotmeta.ref.urlchar