J/ApJ/902/46ivo://CDS.VizieR/J/ApJ/902/46doi:10.26093/cds/vizier.19020046CDSYang Y.Hoeflich P.Baade D.Maund J.R.Wang L.Brown P.J.,Stevance H.F.Arcavi I.Burke J.Cikota A.Clocchiatti A.Gal-Yam A.,Graham M.L.Hiramatsu D.Hosseinzadeh G.Howell D.A.Jha S.W.,McCully C.Patat F.Sand D.J.Schulze S.Spyromilio J.Valenti S.,Vinko J.Wang X.Wheeler J.C.Yaron O.Zhang J.2022-05-18T14:29:21Z2022-04-11T12:45:54ZCDS support team

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

cds-question@unistra.frsupernovaeinfrared-photometryvisible-astronomybroad-band-photometryThe nondetection of companion stars in SN Ia progenitor systems lends support to the notion of double-degenerate systems and explosions triggered by the merging of two white dwarfs. This very asymmetric process should lead to a conspicuous polarimetric signature. By contrast, observations consistently find very low continuum polarization as the signatures from the explosion process largely dominate over the pre-explosion configuration within several days. Critical information about the interaction of the ejecta with a companion and any circumstellar matter is encoded in the early polarization spectra. In this study, we obtain spectropolarimetry of SN 2018gv with the ESO Very Large Telescope at -13.6 days relative to the B-band maximum light, or ~5 days after the estimated explosion-the earliest spectropolarimetric observations to date of any SN Ia. These early observations still show a low continuum polarization (<=0.2%) and moderate line polarization (0.30+/-0.04% for the prominent SiII{lambda}6355 feature and 0.85+/-0.04% for the high-velocity Ca component). The high degree of spherical symmetry implied by the low-line and continuum polarization at this early epoch is consistent with explosion models of delayed detonations and is inconsistent with the merger-induced explosion scenario. The dense UV and optical photometry and optical spectroscopy within the first ~100 days after the maximum light indicate that SN 2018gv is a normal SN Ia with similar spectrophotometric behavior to SN 2011fe.2020ApJ...902...46Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/902/46CatalogResearchIsServedByTAP VizieR generic servicerelated-toVI/135 : All-sky spectrally matched Tycho2 stars (Pickles+, 2010)J/AJ/133/403 : Light curve of 11 type Ia supernovae (Garg+, 2007)J/ApJ/699/L139 : Spectral parameters of SNe Ia (Wang+, 2009)J/AJ/139/120 : Low-redshift Type-Ia supernovae (Folatelli+, 2010)J/ApJ/733/124 : Cepheids in M101 observed with HST (Shappee+, 2011)J/ApJ/745/74 : Pre-maximum spectra of type Ia SNe (Folatelli+, 2012)J/MNRAS/425/1819 : Berkeley supernova Ia program. II. (Silverman+, 2012)J/other/NewA/20.30 : BVRI light curves of 3 SN (Munari+, 2013)J/A+A/554/A27 : 2011fe spectrophotometric time series (Pereira+, 2013)J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 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/MNRAS/451/1973 : Type Ia SNe igh-velocity features (Silverman+, 2015)J/ApJ/813/30 : UV-Optical LCs of the SNIa iPTF14bdn (Smitka+, 2015)J/AJ/149/171 : 2MASS galaxy group catalog (Tully, 2015)J/ApJS/219/13 : SNe Ia light curves for the LSQ-CSP sample (Walker+, 2015)J/ApJS/220/20 : Si and Ca high-velocity features in SNe Ia (Zhao+, 2015)J/AJ/152/102 : Flux conversions for Swift/UVOT filters (Brown+, 2016)J/ApJ/826/56 : HST/WFC3 obs. of Cepheids in SNIa host gal. (Riess+, 2016)J/AJ/151/125 : Optical and UV photometry of SN 2013dy (Zhai+, 2016)J/A+A/608/A146 : Southern Hemisphere ISM FORS2 spectropol. (Bagnulo+, 2017)J/AJ/154/211 : CSP (DR3): photometry of low-z SNe Ia (Krisciunas+, 2017)J/ApJ/853/62 : Opt. & NIR spectra and LCs of SN2016ija (Tartaglia+, 2018)J/ApJ/870/L1 : K2 obs. of type Ia SN 2018oh (Dimitriadis+, 2019)J/ApJ/870/13 : K2 LC alternative analysis of ASASSN-18bt (Shappee+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/902/46https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/902/46http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/902/46https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/902/46https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/902/46http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/902/46GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/ApJ/902/46/table3Las Cumbres Observatory (LCO) UBg'Vr'i' photometry of SN2018gvrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD-U[58134.8/58264.8]? Modified Julian date of U band observation (JD-2400000.5)dtime.epochdoublenullableUmag[12.45/17.47]? U band magnitudemagphot.mag;em.opt.Ufloatnullablee_Umag[0.002/0.112]? Uncertainty in Umagmagstat.error;phot.magfloatnullableMJD-B[58134/58287]? Modified Julian date of B band observation (JD-2400000.5)dtime.epochdoublenullableBmag[12.81/17.41]? B band magnitudemagphot.mag;em.opt.Bfloatnullablee_Bmag[0.001/0.031]? Uncertainty in Bmagmagstat.error;phot.magfloatnullableMJD-V[58134/58287]? Modified Julian date of V band observation (JD-2400000.5)dtime.epochdoublenullableVmag[12.86/17.19]? V band magnitudemagphot.mag;em.opt.Vfloatnullablee_Vmag[0.002/0.03]? Uncertainty in Vmagmagstat.error;phot.magfloatnullableMJD-gp[58134/58287]? Modified Julian date of g' band observation (JD-2400000.5)dtime.epochdoublenullablegpmag[12.81/17.05]? g' band magnitudemagphot.mag;em.opt.Bfloatnullablee_gpmag[0.001/0.018]? Uncertainty in gpmagmagstat.error;phot.magfloatnullableMJD-rp[58134/58287]? Modified Julian date of r' band observation (JD-2400000.5)dtime.epochdoublenullablerpmag[12.93/17.66]? r' band magnitudemagphot.mag;em.opt.Rfloatnullablee_rpmag[0.001/0.033]? Uncertainty in rpmagmagstat.error;phot.magfloatnullableMJD-ip[58134/58287]? Modified Julian date of i' band observation (JD-2400000.5)dtime.epochdoublenullableipmag[13.47/18.06]? i' band magnitudemagphot.mag;em.opt.Ifloatnullablee_ipmag[0.002/0.118]? Uncertainty in ipmagmagstat.error;phot.magfloatnullable