J/A+A/690/A216ivo://CDS.VizieR/J/A+A/690/A216doi:10.26093/cds/vizier.36900216CDSAgui Fernandez J.F.de Ugarte Postigo A.Thoene C.C.Kobayashi S.,Rossi A.Toma K.Jelinek M.Kann D.A.Covino S.Wiersema K.,Hartmann D.Jakobsson P.Martin-Carrillo A.Melandri A.De Pasquale M.,Pugliese G.Savaglio S.Starling R.L.C.Strobl J.Della Valle M.,de Wet S.Zafar T.2025-02-24T20:01:52Z2024-10-10T08:40:19ZCDS support team

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

cds-question@unistra.frgamma-ray-astronomygamma-ray-burstspolarimetryLong gamma ray bursts (GRBs) are produced by the collapse of some very massive stars, which emit ultra-relativistic jets. When the jets collide with the interstellar medium they decelerate and generate the so-called afterglow emission, which has been observed to be polarised. In this work we study the polarimetric evolution of GRB 210610B afterglow, at z=1.1341. This allows to evaluate the role of geometric and/or magnetic mechanisms in the GRB afterglow polarisation. We observed GRB 210610B using imaging polarimetry with CAFOS on the 2.2 m Calar Alto Telescope and FORS2 on the 4x8.1m Very Large Telescope. Complementary optical spectroscopy was obtained with OSIRIS on the 10.4m Gran Telescopio Canarias. We study the GRB light-curve from X-rays to optical bands and the Spectral Energy Distribution (SED). This allows us to strongly constrain the line-of-sight extinction. Finally, we study the GRB host galaxy using optical/NIR data to fit the SED and derive its integrated properties. GRB 210610B had a bright afterglow with a negligible line-of-sight extinction. Polarimetry was obtained at three epochs: during an early plateau phase, at the time when the light curve breaks, and after the light curve steepened. We observe an initial polarisation of ~4% that goes to zero at the time of the break, and then increases again to ~2% with a change of the position angle of 54+/-9deg. The spectrum show features with very low equivalent widths, indicating a small amount of material in the line-of-sight within the host. The lack of dust and the low amount of material on the line-of-sight to GRB 210610B allow us to study the intrinsic polarisation of the GRB optical afterglow. We find the GRB polarisation signals are consistent with ordered magnetic fields in refreshed shock or/and hydrodynamics-scale turbulent fields in the forward shock.2024A&A...690A.216Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/690/A216CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/690/A216https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/690/A216http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/690/A216https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/690/A216https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/690/A216http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/690/A216GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/690/A216/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/690/A216/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/690/A216/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/690/A216/list?GETtext/xml+votable180.050000true238.216278932.888730.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/690/A2166/9733 14688 31721https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/690/A216?format=asciiGamma-raydefaultJ/A+A/690/A216/listList of fits imagesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datestime.epoch;obsnullablesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlchar