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dc.contributor.authorHeesen, V.
dc.contributor.authorE., Buie II
dc.contributor.authorHuff, C. J.
dc.contributor.authorPerez, L. A.
dc.contributor.authorWoolsey, J. G.
dc.contributor.authorRafferty, D. A.
dc.contributor.authorBasu, A.
dc.contributor.authorBeck, R.
dc.contributor.authorBrinks, E.
dc.contributor.authorHorellou, C.
dc.contributor.authorScannapieco, E.
dc.contributor.authorBrüggen, M.
dc.contributor.authorDettmar, R. -J.
dc.contributor.authorSendlinger, K.
dc.contributor.authorNikiel-Wroczyński, B.
dc.contributor.authorChyży, K. T.
dc.contributor.authorBest, P.N.
dc.contributor.authorHeald, George H.
dc.contributor.authorPaladino, R.
dc.date.accessioned2019-01-17T16:15:02Z
dc.date.available2019-01-17T16:15:02Z
dc.date.issued2018-10-15
dc.identifier.citationHeesen , V , E. , B II , Huff , C J , Perez , L A , Woolsey , J G , Rafferty , D A , Basu , A , Beck , R , Brinks , E , Horellou , C , Scannapieco , E , Brüggen , M , Dettmar , R -J , Sendlinger , K , Nikiel-Wroczyński , B , Chyży , K T , Best , P N , Heald , G H & Paladino , R 2018 , ' Calibrating the relation of low-frequency radio continuum to star formation rate at 1 kpc scale with LOFAR ' , Astronomy & Astrophysics . https://doi.org/10.1051/0004-6361/201833905
dc.identifier.issn0004-6361
dc.identifier.otherPURE: 15699439
dc.identifier.otherPURE UUID: a445c726-7893-41c0-bba9-e27120195be0
dc.identifier.otherArXiv: http://arxiv.org/abs/1811.07968v1
dc.identifier.otherORCID: /0000-0002-7758-9699/work/54143418
dc.identifier.otherScopus: 85062047418
dc.identifier.urihttp://hdl.handle.net/2299/20987
dc.description9 figures, 6 tables and 17 pages. This paper is part of the LOFAR surveys data release 1 and has been accepted for publication in a special edition of A&A that will appear in Feb 2019, volume 622. The catalogues and images from the data release will be publicly available on lofar-surveys.org upon publication of the journal. Reproduced with permission from Astronomy & Astrophysics. © 2018 ESO.
dc.description.abstractRadio continuum (RC) emission in galaxies allows us to measure star formation rates (SFRs) unaffected by extinction due to dust, of which the low-frequency part is uncontaminated from thermal (free-free) emission. We calibrate the conversion from the spatially resolved 140 MHz RC emission to the SFR surface density ($\Sigma_{\rm SFR}$) at 1 kpc scale. We used recent observations of three galaxies (NGC 3184, 4736, and 5055) from the LOFAR Two-metre Sky Survey (LoTSS), and archival LOw-Frequency ARray (LOFAR) data of NGC 5194. Maps were created with the facet calibration technique and converted to radio $\Sigma_{\rm SFR}$ maps using the Condon relation. We compared these maps with hybrid $\Sigma_{\rm SFR}$ maps from a combination of GALEX far-ultraviolet and Spitzer 24 $\mu\rm m$ data using plots tracing the relation at $1.2\times 1.2$-kpc$^2$ resolution. The RC emission is smoothed with respect to the hybrid $\Sigma_{\rm SFR}$ owing to the transport of cosmic-ray electrons (CREs). This results in a sublinear relation $(\Sigma_{\rm SFR})_{\rm RC} \propto [(\Sigma_{\rm SFR})_{\rm hyb}]^{a}$, where $a=0.59\pm 0.13$ (140 MHz) and $a=0.75\pm 0.10$ (1365 MHz). Both relations have a scatter of $\sigma = 0.3~\rm dex$. If we restrict ourselves to areas of young CREs ($\alpha > -0.65$; $I_\nu \propto \nu^\alpha$), the relation becomes almost linear at both frequencies with $a\approx 0.9$ and a reduced scatter of $\sigma = 0.2~\rm dex$. We then simulate the effect of CRE transport by convolving the hybrid $\Sigma_{\rm SFR}$ maps with a Gaussian kernel until the RC-SFR relation is linearised; CRE transport lengths are $l=1$-5 kpc. Solving the CRE diffusion equation, we find diffusion coefficients of $D=(0.13$-$1.5) \times 10^{28} \rm cm^2\,s^{-1}$ at 1 GeV. A RC-SFR relation at $1.4$ GHz can be exploited to measure SFRs at redshift $z \approx 10$ using $140$ MHz observations.en
dc.language.isoeng
dc.relation.ispartofAstronomy & Astrophysics
dc.rightsOpen
dc.subjectastro-ph.GA
dc.titleCalibrating the relation of low-frequency radio continuum to star formation rate at 1 kpc scale with LOFARen
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionCentre for Astrophysics Research
dc.description.statusPeer reviewed
dc.relation.schoolSchool of Physics, Astronomy and Mathematics
dc.description.versiontypeFinal Accepted Version
dcterms.dateAccepted2018-10-15
rioxxterms.versionAM
rioxxterms.versionofrecordhttps://doi.org/10.1051/0004-6361/201833905
rioxxterms.licenseref.uriOther
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue
herts.rights.accesstypeOpen


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