J/ApJ/686/1209ivo://CDS.VizieR/J/ApJ/686/1209doi:10.26093/cds/vizier.16861209CDSMelandri A.Mundell C.G.Kobayashi S.Guidorzi C.Gomboc A.,Steele I.A.Smith R.J.Bersier D.Mottram C.J.Carter D.Bode M.F.,O'Brien P.T.Tanvir N.R.Rol E.Chapman R.2017-11-10T11:15:58Z2011-01-12T12:16:09ZCDS support team

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

cds-question@unistra.frWe present a multiwavelength analysis of 63 gamma-ray bursts observed with the world's three largest robotic optical telescopes, the Liverpool and Faulkes Telescopes (North and South). Optical emission was detected for 24 GRBs with brightnesses ranging from R=10 to 22mag in the first 10 minutes after the burst. By comparing optical and X-ray light curves from t=100 to ~106 seconds, we introduce four main classes, defined by the presence or absence of temporal breaks at optical and/or X-ray wavelengths. While 14/24 GRBs can be modeled with the forward-shock model, explaining the remaining 10 is very challenging in the standard framework even with the introduction of energy injection or an ambient density gradient. Early X-ray afterglows, even segments of light curves described by a power law, may be due to additional emission from the central engine. Thirty-nine GRBs in our sample were not detected and have deep upper limits (R<22mag) at early time. Of these, only 10 were identified by other facilities, primarily at near infrared wavelengths, resulting in a dark burst fraction of ~50%. Additional emission in the early-time X-ray afterglow due to late-time central engine activity may also explain some dark bursts by making the bursts brighter than expected in the X-ray band compared to the optical band.2008ApJ...686.1209Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/686/1209CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/626/L5 : Photometric observations of GRB 041006 (Stanek+, 2005)J/ApJ/642/L99 : R-band photometry of GRB 060206 (Wozniak+, 2006)J/ApJ/654/L21 : R-band light curves of GRB 060206 and GRB 060210 (Stanek+,J/ApJ/672/449 : GRB 061126 light curves (Perley+, 2008)http://www.astro.livjm.ac.uk/RoboNet : Index of RoboNethttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/686/1209https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/686/1209http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/686/1209https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/686/1209https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/686/1209http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/686/1209GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/686/1209/table1 (Optical photometry in the R-band of GRB afterglows)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/686/1209/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/686/1209/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/686/1209/table1?GETtext/xml+votable180.050000true13.70904171.23527780.0055555555555555566/500 503 2044 3795 5633 7908 8954 10447 10852 10912 11008 11905 12134 16232 18030 19194 20030 22129 25901 31281 33735 39224 404332.762881831355591e-19 3.3785437584409506e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/686/1209?format=asciiGamma-raydefaultJ/ApJ/686/1209/table1Optical photometry in the R-band of GRB afterglowsExpTotal exposure timemintime.duration;obs.exposurefloatGRBGRB identification (1)meta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDtMean time from the burst eventmintime.intervaldoubleFilterFilter (SDSS-R or Bessel-R)meta.id;instr.filtercharRcmagRc band magnitude (2)magphot.mag;em.opt.Rfloate_Rcmag1-{sigma} error in Rcmagmagstat.error;phot.mag;em.opt.RfloatSimbadSimbad column added by the CDScharNEDSimbad column added by the CDSchar_RAPositions from Simbad (right ascension part)degpos.eq.ra;meta.main_DEPositions from Simbad (declination part)degpos.eq.dec;meta.main