J/A+A/691/A121ivo://CDS.VizieR/J/A+A/691/A121doi:10.26093/cds/vizier.36910121CDSNeumann L.Bigiel F.Barnes A.T.Gallagher M.J.Leroy A.Usero A.,Rosolowsky E.BeslicI.Boquien M.Cao Y.Chevance M.Colombo D.,Dale D.A.Eibensteiner C.Grasha K.Henshaw J.D.Jimenez-Donaire M.J.,Meidt S.Menon S.H.Murphy E.J.Pan H.-A.Querejeta M.Saito T.,Schinnerer E.Stuber S.K.Teng Y.-H.Williams T.G.2025-02-27T20:01:55Z2024-11-01T18:16:14ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiinterstellar-mediumradio-astronomyThe property of star formation rate (SFR) is tightly connected to the amount of dense gas in molecular clouds. However, it is not fully understood how the relationship between dense molecular gas and star formation varies within galaxies and in different morphological environments. Most previous studies have typically been limited to kiloparsec-scale resolution such that different environments could not be resolved. In this work, we present new ALMA observations of HCN(1-0) at 260pc scale to test how the amount of dense gas and its ability to form stars varies with environmental properties. Combined with existing CO(2-1) observations from ALMA and H{alpha} from MUSE, we measured the HCN/CO line ratio, a proxy for the dense gas fraction, and SFR/HCN, a proxy for the star formation efficiency of the dense gas. We find a systematic >1dex increase (decreases) of HCN/CO (SFR/HCN) towards the centre of the galaxy, and roughly flat trends of these ratios (average variations <0.3dex) throughout the disc. While spiral arms, interarm regions, and bar ends show similar HCN/CO and SFR/HCN, on the bar, there is a significantly lower SFR/HCN at a similar HCN/CO. The strong environmental influence on dense gas and star formation in the centre of NGC 4321, suggests either that clouds couple strongly to the surrounding pressure or that HCN emission traces more of the bulk molecular gas that is less efficiently converted into stars. Across the disc, where the ISM pressure is typically low, SFR/HCN is more constant, indicating a decoupling of the clouds from their surrounding environment. The low SFR/HCN on the bar suggests that gas dynamics (e.g. shear and streaming motions) can have a large effect on the efficiency with which dense gas is converted into stars. In addition, we show that HCN/CO is a good predictor of the mean molecular gas surface density at 260pc scales across environments and physical conditions.2024A&A...691A.121Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/691/A121CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/691/A121https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/691/A121http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/691/A121https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/691/A121https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/691/A121http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/691/A121GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/691/A121/list (List of fits datacubes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/691/A121/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/691/A121/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/691/A121/list?GETtext/xml+votable180.050000true185.7279215.822190.0055555555555555566/28035https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/691/A121?format=asciiRadiodefaultJ/A+A/691/A121/listList of fits datacubesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharNzNumber of slicesmeta.numberintRAJ2000Right 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.numberintbVRADLower value of VRAD intervalm/sphys.veloc;pos.heliocentricintBVRADUpper value of VRAD intervalm/sphys.veloc;pos.heliocentricintdVRADVRAD resolutionm/sspect.resolutionfloat