J/A+A/669/A8ivo://CDS.VizieR/J/A+A/669/A8doi:10.26093/cds/vizier.36690008CDSHeesen V.Klocke T.-L.Brueggen M.Tabatabaei F.S.Basu A.Beck R.,Drabent A.Nikiel-WroczyNski B.Paladino R.Schulz S.Stein M.2023-01-18T06:33:14Z2022-12-22T16:11:50ZCDS support team

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

cds-question@unistra.frsurveysradio-continuum-emissiongalaxiesmagnetic-fieldsMagnetic fields are key to understand galaxy evolution, regulating stellar feedback and star formation in galaxies. We probe the origin of magnetic fields in late-type galaxies, measuring magnetic field strengths, exploring whether magnetic fields are only passive constituents of the interstellar medium, or whether they are active constituents being part of the local energy equilibrium. We measure equipartition magnetic field strengths in 39 galaxies from LoTSS-DR2 using LOFAR observations at 144MHz with 6arcsec angular resolution which (0.1-0.7kpc). For a subset of 9 galaxies, we obtain atomic and molecular mass surface densities using HI and CO(2-1) data, from the THINGS and HERACLES surveys, respectively. These data are at 13 arcsec angular resolution, which corresponds to 0.3-1.2kpc at the distances of our galaxies. We measure kinetic energy densities using HI and CO velocity dispersions. We found a mean magnetic field strength of 3.6-12.5uG with a mean of 7.9+/-2.0G across the full sample. The magnetic field strength has the tightest and steepest relation with the total gas surface density with B{prop.to}{Sigma}^0.309+/-0.006^_HI+H2_. The relation with the HI+H2 star-formation rate surface density and molecular gas surface density has significantly flatter slopes. After accounting for the influence of cosmic-ray transport, we found an even steeper relation of B{prop.to}{Sigma}^0.393+/-0.009^_HI+H2_. These results suggest that the magnetic field is regulated by a B-{rho} relation, which has its origin in the saturation of the small-scale dynamo. This is borne out by an agreement of kinetic and magnetic energy densities although local deviations do exist in particular in areas of high kinetic energy densities where the magnetic field is sub-dominant.2023A&A...669A...8Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/669/A8CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/659/A1 : LOFAR Two-metre Sky Survey (LoTSS) DR2 (Shimwell+, 2022)J/A+A/664/A83 : Nearby galaxies in LoTSS-DR2 (Heesen+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/669/A8https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/669/A8http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/669/A8https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/669/A8https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/669/A8http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/669/A8GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/669/A8/table1 (Magnetic field strengths and ancillary data in the LoTSS-DR2 sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/669/A8/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/669/A8/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/669/A8/table1?GETtext/xml+votable180.050000true33.5150527.87717220.005555555555555556Cone search capability for table J/A+A/669/A8/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/669/A8/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/669/A8/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/669/A8/list?GETtext/xml+votable180.050000true33.5148327.876960.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/669/A86/764 2320 2409 5067 5181 5469 5492 5504 5587 5639 5715 5751 5799 5995 6037 7241 7424-7425 7584 7602 7604 10475 10674 10751 10761 10841 10856 10888 10901 10911 10979 10986 11000 11026-11027 11263 11375 11434 13522 281239.54153977050123e-26 9.54153977050123e-26https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/669/A8?format=asciiRadiodefaultJ/A+A/669/A8/table1Magnetic field strengths and ancillary data in the LoTSS-DR2 sampleGalaxyName of the galaxymeta.id;meta.maincharinclInclination angle with respect to the line of sightdegsrc.orbital.inclination;spect.lineintn_MHI[a] Note on MHI (1)meta.notecharMH2? H2 mass from Leroy et al. (2008AJ....136.2782L, Cat. J/AJ/136/2782)1e+08solMassphys.massfloatnullablen_MH2[a] Note on MH2 (1)meta.notecharSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDistDistanceMpcpos.distancefloatleffPath lengthkpcsrc.morph.scLengthfloatS144MHzIntegrated flux density at 144 MHzJyphot.flux.density;em.radio.100-200MHzfloatalpha-intIntegrated radio spectral indexspect.indexfloate_alpha-intIntegrated radio spectral index errorstat.errorfloat<Beq>Mean magnetic field strengthuGphys.magField;phys.atmol.collStrengthfloate_<Beq>Mean magnetic field strength erroruGstat.errorfloatBmax-eqMaximum magnetic field strengthuGphys.magField;phys.atmol.collStrengthfloate_Bmax-eqMaximum magnetic field strength erroruGstat.errorfloatMHI? HI mass from Walter et al. (2008AJ....136.2563W, Cat. J/AJ/136/2563)1e+08solMassphys.massfloatnullable<sigmaHI>? Mean turbulent velocity dispersion for HI gas from Mogotsi et al. (2016AJ....151...15M)km/sphys.veloc.dispersionfloatnullable<sigmaH2>? Mean turbulent velocity dispersion for H2 gas from Mogotsi et al. (2016AJ....151...15M)km/sphys.veloc.dispersionfloatnullablefitsDisplay the fits files listmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/A+A/669/A8/listList of fits imagesNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datestime.epoch;obsnullablesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharGalaxyName of the galaxymeta.id;meta.maincharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlcharrecnoRecord 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.numberint