J/A+A/667/A4ivo://CDS.VizieR/J/A+A/667/A4doi:10.26093/cds/vizier.36670004CDSCai Y-Z.Pastorello A.Fraser M.Wang X.-F.Filippenko A.V.,Reguitti A.Patra K.C.Goranskij V.P.Barsukova E.A.Brink T.G.,Elias-Rosa N.Stevance H.F.Zheng W.Yang Y.Atapin K.E.Benetti S.,de Boer T.J.L.Bose S.Burke J.Byrne R.Cappellaro E.Chambers K.C.,Chen W.-L.Emami N.Gao H.Hiramatsu D.Howell D.A.Huber M.E.,Kankare E.Kelly P.L.Kotak R.Kravtsov T.Lander V.Yu.Li Z.-T.,Lin C.-C.Lundqvist P.Magnier E.A.Malygin E.A.Maslennikova N.A.,Matilainen K.Mazzali P.A.McCully C.Mo J.Moran S.Newsome M.,Oparin D.V.Padilla Gonzalez E.Reynolds T.M.Shatsky N.I.Smartt S.J.,Smith K.W.Stritzinger M.D.Tatarnikov A.M.Terreran G.Uklein R.I.,Valerin G.Vallely P.J.Vozyakova O.V.Wainscoat R.Yan S.-Y.,Zhang J.-J.Zhang T.-M.Zheltoukhov S.G.Dastidar R.Fulton M.,Galbany L.Gangopadhyay A.Ge H.-W.Gutierrez C.P.Lin H.Misra K.,Ou Z.-W.Salmaso I.Tartaglia L.Xiao L.Zhang X.-H.2024-11-06T20:01:14Z2022-10-28T09:29:32ZCDS support team

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

cds-question@unistra.frvariable-starsgalaxiesvisible-astronomysloan-photometryinfrared-photometrybroad-band-photometryWe present an observational study of the luminous red nova (LRN) AT 2021biy in the nearby galaxy NGC 4631. The field of the object was routinely imaged during the pre-eruptive stage by synoptic surveys, but the transient was detected only at a few epochs from ~231 days before maximum brightness. The LRN outburst was monitored with unprecedented cadence both photometrically and spectroscopically. AT 2021biy shows a short-duration blue peak, with a bolometric luminosity of ~1.6x10^41^erg/s, followed by the longest plateau among LRNe to date, with a duration of 210 days. A late-time hump in the light curve was also observed, possibly produced by a shell-shell collision. AT 2021biy exhibits the typical spectral evolution of LRNe. Early-time spectra are characterised by a blue continuum and prominent H emission lines. Then, the continuum becomes redder, resembling that of a K-type star with a forest of metal absorption lines during the plateau phase. Finally, late-time spectra show a very red continuum (TBB~=2050K) with molecular features (e.g., TiO) resembling those of M-type stars. Spectropolarimetric analysis indicates that AT 2021biy has local dust properties similar to those of V838 Mon in the Milky Way Galaxy. Inspection of archival Hubble Space Telescope data taken on 2003 August 3 reveals a ~20M_{sun}_ progenitor candidate with log(L/L_{sun}_)=5.0dex and Teff=5900K at solar metallicity. The above luminosity and colour match those of a luminous yellow supergiant. Most likely, this source is a close binary, with a 17-24M_{sun}_ primary component.2022A&A...667A...4Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/667/A4CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/646/A119 : M31 luminous red nova AT 2019zhd photometry (Pastorello+ 2021)J/A+A/647/A93 : AT 2020hat and AT 2020kog light curves (Pastorello+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/667/A4https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/667/A4http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/667/A4https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/667/A4https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/667/A4http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/667/A4GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap4.070063233561695e-19 5.042107639525881e-19OpticalInfrareddefaultJ/A+A/667/A4/tablea1Johnson-Cousins B band light curve of AT 2021biyDateDate of observation (YYYY/MM/DD)time.epochnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian Datedtime.epochdoubleBand[BV] Band (Johnson-Cousins)instr.bandpasscharl_magLimit flag on magmeta.code.errorcharmagJohnson-Cousins magnitude in Bandmagphot.magfloate_mag? Johnson-Cousins magnitude in Band errormagstat.error;phot.magfloatnullableInstInstrument namemeta.id;instrcharJ/A+A/667/A4/tablea2Johnson-Cousins V band light curve of AT 2021biyl_magLimit flag on magmeta.code.errorcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochdoubleBand[BV] Band (Johnson-Cousins)instr.bandpasscharmagJohnson-Cousins magnitude in Bandmagphot.magfloate_mag? Johnson-Cousins magnitude in Band errormagstat.error;phot.magfloatnullableInstInstrument namemeta.id;instrcharJ/A+A/667/A4/tablea3Sloan u band light curve of AT 2021biyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochdoubleBand[ugriz] Band (Sloan)instr.bandpasscharl_magLimit flag on magmeta.code.errorcharmagSloan magnitude in Bandmagphot.magfloate_mag? Sloan magnitude in Band errormagstat.error;phot.magfloatnullableInstInstrument namemeta.id;instrcharNote[a] Notes (1)meta.notecharJ/A+A/667/A4/tablea4Sloan g band light curve of AT 2021biyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochdoubleBand[ugriz] Band (Sloan)instr.bandpasscharl_magLimit flag on magmeta.code.errorcharmagSloan magnitude in Bandmagphot.magfloate_mag? Sloan magnitude in Band errormagstat.error;phot.magfloatnullableInstInstrument namemeta.id;instrcharNote[a] Notes (1)meta.notecharJ/A+A/667/A4/tablea5Sloan r band light curve of AT 2021biyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochdoubleBand[ugriz] Band (Sloan)instr.bandpasscharl_magLimit flag on magmeta.code.errorcharmagSloan magnitude in Bandmagphot.magfloate_mag? Sloan magnitude in Band errormagstat.error;phot.magfloatnullableInstInstrument namemeta.id;instrcharNote[a] Notes (1)meta.notecharJ/A+A/667/A4/tablea6Sloan i band light curve of AT 2021biyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochdoubleBand[ugriz] Band (Sloan)instr.bandpasscharl_magLimit flag on magmeta.code.errorcharmagSloan magnitude in Bandmagphot.magfloate_mag? Sloan magnitude in Band errormagstat.error;phot.magfloatnullableInstInstrument namemeta.id;instrcharNote[a] Notes (1)meta.notecharJ/A+A/667/A4/tablea7Sloan z band light curve of AT 2021biymagSloan magnitude in Bandmagphot.magfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochdoubleBand[ugriz] Band (Sloan)instr.bandpasscharl_magLimit flag on magmeta.code.errorchare_mag? Sloan magnitude in Band errormagstat.error;phot.magfloatnullableInstInstrument namemeta.id;instrcharNote[a] Notes (1)meta.notecharJ/A+A/667/A4/tablea8ATLAS cyan band light curve of AT 2021biyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochcharBand[co] Band (ATLAS, c for cyan, o for orange)instr.bandpasscharl_magLimit flag on magmeta.code.errorcharmagATLAS magnitude in Bandmagphot.magfloate_mag? ATLAS magnitude in Band errormagstat.error;phot.magfloatnullableJ/A+A/667/A4/tablea9ATLAS orange band light curve of AT 2021biye_mag? ATLAS magnitude in Band errormagstat.error;phot.magfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochcharBand[co] Band (ATLAS, c for cyan, o for orange)instr.bandpasscharl_magLimit flag on magmeta.code.errorcharmagATLAS magnitude in Bandmagphot.magfloatJ/A+A/667/A4/tablea10Pan-STARRS i band light curve of AT 2021biyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochdoubleBand[izy] Band (Pan-STARRS)instr.bandpasscharl_magLimit flag on magmeta.code.errorcharmagPan-STARRS magnitude in Bandmagphot.magfloate_mag? Pan-STARRS magnitude in Band errormagstat.error;phot.magfloatnullableJ/A+A/667/A4/tablea11Pan-STARRS z band light curve of AT 2021biyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochdoubleBand[izy] Band (Pan-STARRS)instr.bandpasscharl_magLimit flag on magmeta.code.errorcharmagPan-STARRS magnitude in Bandmagphot.magfloate_mag? Pan-STARRS magnitude in Band errormagstat.error;phot.magfloatnullableJ/A+A/667/A4/tablea12Pan-STARRS y band light curve of AT 2021biyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochdoubleBand[izy] Band (Pan-STARRS)instr.bandpasscharl_magLimit flag on magmeta.code.errorcharmagPan-STARRS magnitude in Bandmagphot.magfloate_mag? Pan-STARRS magnitude in Band errormagstat.error;phot.magfloatnullableJ/A+A/667/A4/tablea13*Near-infrared (NIR) YJHK light curves of AT 2021biyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (YYYY/MM/DD)time.epochnullableMJDModified Julian Datedtime.epochdoublePhasePhase relative to r-band maximum light (1)dtime.intervalfloatYmag? NIR Y band magnitudemagphot.mag;em.IR.JfloatnullableJmag? NIR J band magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag? NIR J band magnitude error (2)magstat.error;phot.magfloatnullableHmag? NIR H band magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag? NIR H band magnitude error (2)magstat.error;phot.magfloatnullableKmag? NIR K band magnitudemagphot.mag;em.IR.Kfloatnullablee_Kmag? NIR K band magnitude error (2)magstat.error;phot.magfloatnullableInstInstrument namemeta.id;instrchar