J/A+A/642/A118ivo://CDS.VizieR/J/A+A/642/A118doi:10.26093/cds/vizier.36420118CDSKierdorf M.Mao S.A.Beck R.Basu A.Fletcher A.Horellou C.,Tabatabaei F.Ott J.Haverkorn M.2021-01-05T09:15:18Z2020-10-12T10:12:41ZCDS support team

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

cds-question@unistra.frgalaxiesmagnetic-fieldsAn excellent laboratory for studying large scale magnetic fields is the grand design face-on spiral galaxy M51. Due to wavelength-dependent Faraday depolarization, linearly polarized synchrotron emission at different radio frequencies gives a picture of the galaxy at different depths: Observations at L-band (1-2GHz) probe the halo region while at C- and Xband (4-8GHz) the linearly polarized emission probe the disk region of M51. We present new observations of M51 using the Karl G. Jansky Very Large Array (VLA) at S-band (2-4GHz), where previously no polarization observations existed, to shed new light on the transition region between the disk and the halo. We discuss a model of the depolarization of synchrotron radiation in a multilayer magneto-ionic medium and compare the model predictions to the multi-frequency polarization data of M51 between 1-8GHz. The new S-band data are essential to distinguish between different models. Our study shows that the initial model parameters, i.e. the total regular and turbulent magnetic field strengths in the disk and halo of M51, need to be adjusted to successfully fit the models to the data.2020A&A...642A.118Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/642/A118CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/568/A74 : Low-frequency (115-175MHz) image of M51 (Mulcahy+, 2014)J/A+A/592/A123 : M51 total intensity image at 333MHz (Mulcahy+, 2016)J/A+A/593/A118 : HCN(1-0) cube for the nucleus of M51 (Querejeta+, 2016)J/A+A/617/A136 : LOFAR M51 field low-frequency polarized sourcesJ/A+A/625/A19 : 33 GHz continuum map of M51 (Querejeta+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/642/A118https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/642/A118http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/642/A118https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/642/A118https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/642/A118http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/642/A118GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/642/A118/list (List of fits files)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/642/A118/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/642/A118/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/642/A118/list?GETtext/xml+votable180.050000true202.4840347.230420.0055555555555555566/11027https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/642/A118?format=asciidefaultJ/A+A/642/A118/listList of fits filesNxNumber of pixels along X-axismeta.numberintrecnoRecord 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.mainNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datestime.epoch;obsnullableFreq? Observed frequencyGHzem.freqdoublenullablesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar