J/A+A/672/A21ivo://CDS.VizieR/J/A+A/672/A21doi:10.26093/cds/vizier.36720021CDSHeesen V.de Gasperin F.Schulz S.Basu A.Beck R.Brueggen M.,Dettmar R.-J.Stein M.Gajovic L.Tabatabaei F.S.Reichherzer P.2024-11-06T20:03:33Z2023-03-23T08:36:39ZCDS support team

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

cds-question@unistra.frsurveysradio-continuum-emissiongalaxiesThe details of cosmic-ray transport have a strong impact on galaxy evolution. The peak of the cosmic-ray energy distribution is observable in the radio continuum using the electrons as proxy. We measure the length that the cosmic-ray electrons (CRE) are transported during their lifetime in the nearby galaxy M 51 across one order of magnitude in cosmic-ray energy (approximately 1-10GeV). To this end we use new ultra-low frequency observations from the LOw Frequency ARay (LOFAR) at 54 MHz and ancillary data between 144 and 8350MHz. As the the CRE originate from supernova remnants, the radio maps are smoothed in comparison to the distribution of the star formation. By convolving the map of the star-formation rate (SFR) surface density with a Gaussian kernel, we can linearise the radio-SFR relation. The best-fitting convolution kernel is then our estimate of the CRE transport length. We find that the CRE transport length increases at low frequencies, as expected since the CRE have longer lifetimes. The CRE transport length is lCRE = QSRT(4Dtsyn), where D is the isotropic diffusion coefficient and rsyn is the CRE lifetime as given by synchrotron and inverse Compton losses. We find that the data can be well fitted by diffusion, where D=(2.14+/-0.13)x10^28^cm^2^/s. With D{prop.to}E^0.001+/-0.185^, the diffusion coefficient is independent of the CRE energy E in the range considered. Our results suggest that the transport of GeV-cosmic ray electrons in the star-forming discs of galaxies is governed by energy-independent diffusion.2023A&A...672A..21Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/672/A21CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/648/A104 : LOFAR LBA Sky Survey. I. (de Gasperin+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/672/A21https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/672/A21http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/672/A21https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/672/A21https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/672/A21http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/672/A21GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/672/A21/list (Information on fits image)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/672/A21/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/672/A21/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/672/A21/list?GETtext/xml+votable180.050000true199.4447247.220540.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/672/A216/11023https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/672/A21?format=asciiRadiodefaultJ/A+A/672/A21/listInformation on fits imagerecnoRecord 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.numberintFreqObserved frequencyHzem.freqdoublesizeSize 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