J/ApJ/960/29ivo://CDS.VizieR/J/ApJ/960/29CDSPearson J.Sand D.J.Lundqvist P.Galbany L.Andrews J.E.,Bostroem K.A.Dong Y.Hoang E.Hosseinzadeh G.Janzen D.,Jencson J.E.Lundquist M.J.Mehta D.Meza Retamal N.Shrestha M.,Valenti S.Wyatt S.Anderson J.P.Ashall C.Auchettl K.Baron E.,Blondin S.Burns C.R.Cai Y.Chen T.-W.Chomiuk L.Coulter D.A.,Cross D.Davis K.W.de Jaeger T.DerKacy J.M.Desai D.D.,Dimitriadis G.Do A.Farah J.R.Foley R.J.Gromadzki M.,Gutierrez C.P.Haislip J.Gonzalez Hernandez J.I.Hinkle J.T.,Hoogendam W.B.Howell D.A.Hoeflich P.Hsiao E.Huber M.E.Jha S.W.,Jimenez Palau C.Kilpatrick C.D.Kouprianov V.Kumar S.Kwok L.A.,Larison C.LeBaron N.Le Saux X.Lu J.McCully C.Mera Evans T.,Milne P.Modjaz M.Morrell N.Muller-Bravo T.E.Newsome M.,Nicholl M.Padilla Gonzalez E.Payne A.V.Pellegrino C.Phan K.,Pineda-Garcia J.Piro A.L.Piscarreta L.Polin A.Reichart D.E.,Rojas-Bravo C.Ryder S.D.Salmaso I.Schwab M.Shahbandeh M.,Shappee B.J.Siebert M.R.Smith N.Strader J.Taggart K.Terreran G.,Tinyanont S.Tucker M.A.Valerin G.Young D.R.2026-04-02T08:49:01Z2026-04-02T09:45:13ZCDS support team

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

cds-question@unistra.frsupernovaeinfrared-photometryvisible-astronomybroad-band-photometryultraviolet-photometryWe present optical, infrared, ultraviolet, and radio observations of SN 2022xkq, an underluminous fast-declining Type Ia supernova (SN Ia) in NGC 1784 (D~31Mpc), from <1 to 180 days after explosion. The high-cadence observations of SN 2022xkq, a photometrically transitional and spectroscopically 91bg-like SN Ia, cover the first days and weeks following explosion, which are critical to distinguishing between explosion scenarios. The early light curve of SN 2022xkq has a red early color and exhibits a flux excess that is more prominent in redder bands; this is the first time such a feature has been seen in a transitional/91bg-like SN Ia. We also present 92 optical and 19 near-infrared (NIR) spectra, beginning 0.4 days after explosion in the optical and 2.6 days after explosion in the NIR. SN 2022xkq exhibits a long-lived CI 1.0693{mu}m feature that persists until 5 days post-maximum. We also detect CII{lambda}6580 in the pre-maximum optical spectra. These lines are evidence for unburnt carbon that is difficult to reconcile with the double detonation of a sub-Chandrasekhar mass white dwarf. No existing explosion model can fully explain the photometric and spectroscopic data set of SN_2022xkq, but the considerable breadth of the observations is ideal for furthering our understanding of the processes that produce faint SNe Ia.2024ApJ...960...29Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/960/29CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/AJ/128/16 : HIPASS Bright Galaxy Catalog (Koribalski+, 2004)J/ApJ/659/122 : Improved distances to type Ia supernovae (Jha+, 2007)J/ApJ/699/L139 : Spectral parameters of SNe Ia (Wang+, 2009)J/AJ/139/120 : Low-redshift Type-Ia supernovae (Folatelli+, 2010)J/MNRAS/412/1441 : SNe luminosity functions (Li+, 2011)J/AJ/143/126 : Spectroscopy of 462 nearby Type Ia SNe (Blondin+, 2012)J/ApJ/745/74 : Pre-maximum spectra of type Ia SNe (Folatelli+, 2012)J/MNRAS/444/3258 : Velocities and EW of PTF SNe Ia (Maguire+, 2014)J/MNRAS/438/L101 : First month on SN 2013ej (Valenti+, 2014)J/MNRAS/446/3895 : The rising light curves of Type Ia SNe (Firth+, 2015)J/A+A/578/A9 : Optical and NIR spectra of SN iPTF13ebh (Hsiao+, 2015)J/MNRAS/451/1973 : Type Ia SNe high-velocity features (Silverman+, 2015)J/A+A/579/A40 : PESSTO catalog (Smartt+, 2015)J/AJ/152/50 : Cosmicflows-3 catalog (CF3) (Tully+, 2016)J/MNRAS/459/3939 : Type II supernova light curves (Valenti+, 2016)J/ApJ/869/56 : Updated calibration of CSP-I SNe Ia (Burns+, 2018)J/A+A/611/A58 : SN 2007on and SN 2011iv light curves (Gall+, 2018)J/ApJ/853/62 : Opt. and NIR sp. and LCs of SN2016ija (Tartaglia+, 2018)J/ApJ/870/L1 : K2 obs. of type Ia SN 2018oh (Dimitriadis+, 2019)J/A+A/630/A76 : SN2016hnk photometry and spectroscopy (Galbany+, 2019)J/ApJ/870/13 : K2 LC analysis of ASASSN-18bt (Shappee+, 2019)J/MNRAS/486/5785 : Type Ia supernova (Siebert+, 2019)J/ApJ/902/48 : ZTF early obs. of type Ia supernovae. III. (Bulla+, 2020)J/A+A/634/A37 : TURTLS LCs of ^56^Ni distributions (Magee+, 2020)J/ApJ/898/56 : UVOT, ZTF gri LCs and sp. of SNIa 2019yvq (Miller+, 2020)J/ApJ/902/47 : ZTF early obs. of type Ia SNe. II. (Miller+, 2020)J/ApJ/897/159 : Type Ia SN 2019ein UBVgri phot. (Pellegrino+, 2020)J/ApJ/902/46 : LCO network light curves of SN Ia 2018gv (Yang+, 2020)J/A+A/649/A155 : Impact of core and shell masses on SNe Ia (Gronow+, 2021)J/ApJ/923/L8 : Follow-up phot. & sp. of SNIa 2020hvf (Jiang+, 2021)J/ApJ/922/21 : Type Ia SN 2020nlb opt. phot. & spectra (Sand+, 2021)J/ApJ/914/57 : Follow-up Opt. & NIR obs. of SNIa SN2015bp (Wyatt+, 2021)J/ApJ/934/102 : Follow-up LCO phot. & spectra of SN 2016dsg (Dong+, 2022)J/ApJ/933/L45 : LCs and sp. of type Ia SN 2021aefx (Hosseinzadeh+, 2022)J/ApJ/927/142 : Type Ia SN 2012ij opt. & NIR spectra (Li+, 2022)J/ApJS/266/9 : Young Supernova Experiment (YSE) DR1 (Aleo+, 2023)J/ApJ/956/108 : TESS 4yrs obs. of Type Ia supernovae (Fausnaugh+, 2023)J/other/Nat/617.477 : SN 2020eyj optical photometry (Kool+, 2023)J/ApJ/958/178 : SN 2022joj optical and UV phot. follow-up (Liu+, 2023)J/ApJ/946/7 : BVI LCs and sp. of Type Ia SN 2018aoz (Ni+, 2023)J/ApJ/943/L20 : Phot. obs. of SN 2022ilv & SN 2020hvf (Srivastav+, 2023)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/960/29https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/960/29http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/960/29https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/960/29https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/960/29http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/960/29GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapUVOpticalInfrareddefaultJ/ApJ/960/29/fig2SN 2022xkq light curvesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD[59861.2/60044.75] Modified Julian Datedtime.epochdoubleFiltFilter identifiermeta.id;instr.filtercharl_mag[False/True ] Non detection flag (1)meta.code.errorcharmag[14.4/21.1] Apparent magnitude in Filt (1)magphot.magfloate_mag[0/0.4]? Uncertainty in mag (1)magstat.error;phot.magfloatnullabler_magSource of the mag (2)meta.refchar