J/ApJ/902/55ivo://CDS.VizieR/J/ApJ/902/55doi:10.26093/cds/vizier.19020055CDSChandra P.Chevalier R.A.Chugai N.Milisavljevic D.Fransson C.2022-06-13T12:06:32Z2022-05-03T14:14:33ZCDS support team

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

cds-question@unistra.frsupernovaex-ray-sourcesradio-sourcesWe carry out a comprehensive analysis of supernova SN 2001em covering a period of 19yr since discovery. SN 2001em is the oldest supernova known to have undergone a metamorphosis from a stripped envelope to an interacting supernova. An early spectrum indicates it exploded as a Type Ib supernova. Later, the ejecta caught up with a dense circumstellar H-shell, ejected a few thousand years before the explosion, triggering interaction between the supernova ejecta and the dense shell, producing radio, X-ray, and H{alpha} emission. We use archival data with the Very Large Array in radio bands and with Chandra, XMM-Newton, and Swift-XRT in X-ray bands, along with published H{alpha} measurements. We combine these data with our low radio frequency observations with the Giant Metrewave Radio Telescope at two epochs covering three frequencies. While the observations missed the phase when the shock entered the dense shell, the X-rays indicate that the shock came out of the dense shell at around 1750d. The data suggest a forward shock origin of the X-ray emission. Radio data show a spectral inversion at late epochs (>5000d) at around 3GHz, which mimics the properties of the central absorbed component seen in SN 1986J. A possible explanation for this component is that the progenitor of SN 2001em was a massive binary system that had undergone a period of common-envelope evolution. The hydrogen envelope from the SN 2001em progenitor may have been lost as a result of binary interaction.2020ApJ...902...55Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/902/55CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/sn : Asiago Supernova Catalogue (Barbon et al., 1999-)B/swift : Swift Master Catalog (HEASARC, 2004-)B/xmm : XMM-Newton Obs. Log (XMM-Newton Science Operation Center, 2012)B/chandra : The Chandra Archive Log (CXC, 1999-2014)J/AJ/119/32 : Survey of galaxies within nearby voids. II (Grogin+, 2000)J/ApJ/781/42 : Optical photometry of SN 2010jl (Ofek+, 2014)J/ApJ/832/108 : Spectral properties of Type Ic & Ic-bl SNe (Modjaz+, 2016)J/ApJS/241/38 : A comprehensive analysis of Spitzer supernovae (Szalai+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/902/55https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/902/55http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/902/55https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/902/55https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/902/55http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/902/55GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapX-rayRadiodefaultJ/ApJ/902/55/table1Radio observations of SN 2001emrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObs[2003/2020] Year of the observation; UTtime.epochConfigTelescope array configuration; VLA onlyinstr.setupcharPropProposal identifiermeta.id;obscharAge[764/6881] Days from date of explosion: 2001 September 13 (UT)dtime.ageintFreq[0.4/33] FrequencyGHzem.freqfloatMajAxis[0.0009/42.4] Resolution of major axisarcsecphys.angSizefloatMinAxis[0.0008/38] Resolution of minor axisarcsecphys.angSize;srcfloatf_FluxLimit or approximate flag on Fluxmeta.codecharFlux[0.05/2.17] Flux density at FreqmJyphot.flux.density;em.radiofloate_Flux[0.008/0.4]? Uncertainty in FluxmJystat.error;phot.fluxfloatnullableRefReference (1)meta.ref;pos.framecharJ/ApJ/902/55/table2*X-ray observations of SN 2001emf_NHFlag on NHmeta.codecharl_FluxLimit flag on Fluxmeta.code.error;phot.fluxcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (UT) or Lower range datetime.epochnullableDate2Upper range date of observation if anytime.epoch;obs;stat.maxnullableTelTelescopemeta.id;instr.telcharPID1First observation program identifiermeta.id;obsPID2? Second Swift observation program identifiermeta.id;obsnullablePID3? Third Swift observation program identifiermeta.id;obsnullableExp[0.2/19.7] Exposure timekstime.duration;obs.exposurefloatAge[934/5454] Days from date of explosion: 2024 September 13 (UT)dtime.ageinte_Age[1/7]? Age uncertaintydstat.error;time.ageintnullablel_CRLimit flag on CRmeta.code.errorcharCR[0.0008/0.06] X-ray count ratect/sphot.count;em.X-raydoublee_CR[0.0006/0.006]? CR uncertaintyct/sstat.errordoublenullableNH[1.3e-21/2.7e-21] Column densitycm**-2phys.columnDensitydoublee_NH[5.9e-22/1.8e-21]? NH uncertaintycm**-2stat.errordoublenullableFlux[1.4e-14/3.6e-12] Unabosorbed flux in 0.3-10keV energy range in erg/cm^2^/smW.m**-2phot.flux;em.X-raydoublee_Flux[8.1e-15/2.3e-14]? Flux uncertaintymW.m**-2stat.error;phot.fluxdoublenullable