J/ApJ/859/134ivo://CDS.VizieR/J/ApJ/859/134doi:10.26093/cds/vizier.18590134CDSLaskar T.Berger E.Margutti R.Zauderer B.A.Williams P.K.G.,Fong W.-F.Sari R.Alexander K.D.Kamble A.2024-09-05T20:09:26Z2019-06-27T07:31:22ZCDS support team

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

cds-question@unistra.frgamma-ray-astronomygamma-ray-burstsvisible-astronomyradio-continuum-emissionWe present detailed multifrequency, multiepoch radio observations of GRB 140304A at z=5.283 from 1 to 86GHz and from 0.45 to 89days. The radio and millimeter data exhibit unusual multiple spectral components, which cannot be simply explained by standard forward and reverse shock scenarios. Through detailed multiwavelength analysis spanning radio to X-rays, we constrain the forward shock parameters to E_k,iso_~4.9x10^54^erg, A_*_~2.6x10^-2^, {epsilon}_e_~2.5x10^-2^, {epsilon}_B_~5.9x10^-2^, p~2.6, and {theta}_jet_~1.1{deg}, yielding a beaming-corrected {gamma}-ray and kinetic energy, E_{gamma}_~2.3x10^49^erg and E_K_~9.5x10^50^erg, respectively. We model the excess radio emission as due to a combination of a late-time reverse shock (RS) launched by a shell collision, which also produces a rebrightening in the X-rays at ~0.26days, and either a standard RS or diffractive interstellar scintillation (ISS). Under the standard RS interpretation, we invoke consistency arguments between the forward and reverse shocks to derive a deceleration time, t_dec_~100s, the ejecta Lorentz factor, {Gamma}(t_dec_)~300, and a low RS magnetization, R_B_~0.6. Our observations highlight both the power of radio observations in capturing RS emission and thus constraining the properties of GRB ejecta and central engines and the challenge presented by ISS in conclusively identifying RS emission in GRB radio afterglows.2018ApJ...859..134Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/859/134CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/MNRAS/397/1177 : Swift-XRT observations of GRBs (Evans+, 2009)J/A+A/560/A70 : GRB 100621A unusual afterglow (Greiner+, 2013)J/A+A/562/A29 : GRB 100814A GROND and UVOT light curves (Nardini+, 2014)J/ApJ/781/37 : Multi-band photometry of GRB 130427A (Perley+, 2014)J/ApJ/814/1 : GRB 120326A, 100418A, 100901A multi-lambda obs. (Laskar+, 2015)J/ApJ/858/65 : VLA study of high-redshift GRBs. I. GRB140311A (Laskar+, 2018)http://www.swift.ac.uk/xrt_positions/00590206/ : Swift-XRT enhanced positionhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/859/134https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/859/134http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/859/134https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/859/134https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/859/134http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/859/134GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapGamma-rayOpticalRadiodefaultJ/ApJ/859/134/table2Swift UVOT observations of GRB 140304AFiltSwift/UVOT filter usedinstr.setup;instr.filtercharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDeltaT[0.003/6.7] Days since discovery on 2014 March 4 at 13:22:31 UTdtime.epochdoubleFlux[9.5/409] The 3{sigma} flux density upper limitmJyphot.flux.densitydoubleJ/ApJ/859/134/table3Optical observations of GRB 140304ArecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDeltaT[0.0009/1.6] Time since discovery on 2014 March 4 at 13:22:31 UTdtime.epochdoubleTelObservatory identifier ("HJT", "ICATE" or "NOT")meta.id;instr.obstycharInstInstrument identifier ("RATIR", "MASTER" or "ALFOSC")meta.id;instrcharFiltFilter used (1)instr.setup;instr.filtercharFreq[1.8e+14/4.6e+14] Midpoint frequency of FiltHzem.freqdoubleFlux[0.002/0.8] Flux density in Filter (2)mJyphot.flux.density;em.optdoublee_Flux[0.0008/0.2] Uncertainty in Flux (2)mJystat.error;phot.fluxdoubleDet?Detection?; 1=Yesmeta.codeintRefGCN referencemeta.ref;pos.framecharJ/ApJ/859/134/table4GRB 140304A: log of radio observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDeltaT[0.4/89.1] Days since discovery on 2014 March 4 at 13:22:31 UTdtime.epochdoubleTelFacility identifier ("VLA" or "CARMA")meta.id;meta.maincharFreq[1.4/85.5] Frequency of the radio observationGHzem.freq;obsfloatFlux[0.02/1.2] Flux density at FreqmJyphot.flux.density;em.radiodoublee_Flux[0.01/0.4] Uncertainty in FluxmJystat.error;phot.fluxdoubleDet?Detection?; 1=Yesmeta.codeint